Ekihandiiko eki n’ekicweka ky’omutwe gw’okucondooza “Eby’obuhangwa eby’omurembe n’emiringo y’okugaruzaho eby’obuhangwa (SOC)”. Reeba ebihandiiko 14 byona
Ebirungo by‘omubiri ebiine oburemeezi bukye (PAHs) nk‘eby‘okurya ebirimu ebiriisa by‘omubiri (PAHs) nk‘eby‘okurya ebirimu ebiriisa by‘omubiri (methylnaphthalene, asidi y‘omubiri, 1-naphthyl-N-methylcarbamate, n‘ebindi) nibikoresibwa munonga omu makorero gatari gamwe na gamwe kandi nibireeta obutwa bw‘omubiri nari obutwa bw‘omubiri, obutwa bw‘emotoka/ obutwa bw‘omubiri. Ebirungo ebi eby’obuhangwa (SOCs) nari xenobiotics nibitwarwa nk’ebintu ebirikushiisha munonga kandi nibireetaho akabi k’amaani aha by’obuhangwa bw’ensi yoona n’amagara g’abantu. Obuhango bw‘emirimo y‘abantu (nk‘okuhindura amakara kuba gaasi, okushemeza amajuta, okushohoza omu motoka n‘okukoresa eby‘obuhingi) nibimanyisa okuta omutima, okuhendera n‘okutwarwa kw‘ebintu ebi ebiri hoona kandi ebigumire. Oyihireho emiringo y‘okujanjaba/okuihaho eby‘omubiri n‘eby‘emibazi, tekinologiya y‘ebishaka n‘ey‘obuhangwa nk‘okujanjaba eby‘obuhangwa, erikukoresa obukooko obukye oburikubaasa kusheenya kimwe POCs nari kuzihindura omu bihingwa ebitari by‘obutwa, zirugireyo nk‘omuringo ogundi ogutarimu kabi, ogutarikutwara sente nyingi kandi ogurikuhwera. Ebika bya bacteria ebitari bimwe na bimwe ebiri omu kika kya Proteobacteria (obukooko obutarikushushana, obukooko obutarikushushana, obukooko obutarikushushana, obukooko obutarikushushana, obukooko obutarikushushana), Firmicutes (Bacillus na Paenibacillus), na Actinobacteria (Rhodococcus na Arthrobacter ziine obukooko obukye omu) ebirungo by’ebihangwa ebitari bimwe na bimwe. Okucondooza aha by’okurya, genomics, n’okucondooza aha metagenomic nibituhwera kwetegyereza oburemeezi bw’eby’okurya n’obutashushana oburi omu miringo y’amagara egi eyorobi, erikubaasa kwongyera kukozesebwa omu kusheenya eby’obuhangwa omu muringo murungi. Okubaho kwa PAHs kumara obwire buraingwa kureetsireho okurugayo kw’ebintu bisya ebirikusheenyagurika kurabira omu kuhindura ebiri omu nkora y’obuzaarwa orikukoresa ebintu by’obuzaarwa nka plasmids, transposons, bacteriophages, ebizinga by’obuzaarwa, n’ebintu ebirikuteerana. Enkora y‘ebihangirwe n‘eby‘obuzaarwa bw‘ebicweka by‘omubiri ebitari bimwe na bimwe nari eby‘okureeberaho by‘ebyanga (ebibiina) nibibaasa kushoboorora okushoboorora okuhikire, okwa juba kandi okuhikire okwa PAHs ezi kurabira omu bikorwa by‘okukoragana. Omu kucondooza oku, nituta omutima aha miringo y‘okuhindura eby‘okurya etari emwe n‘emwe n‘obutashushana, obukomooko bw‘obuzaarwa n‘obutashushana, n‘okugarukamu/okuhindura kw‘obutafaari bwa naphthalene n‘obukooko oburikushiisha naphthalene oburikuhindurwa. Eki nikiija kuha amakuru g’eby’obuhangwa g’okukoresa omu misiri n’okutunguura ebiriisa ahabw’okuboneza gye eby’obuhangwa.
Entunguuka y’ahonaaho ey’amakorero (eby’amajuta, eby’obuhingi, eby’emibazi, erangi z’emyenda, eby’okujwara, n’ebindi) kireetaireho okutunguuka omu by’entaasya omu nsi yoona n’okutunguura embeera z’abantu. Entunguuka egi ey’amaani ereetsireho okukora ebintu bingi ebikozirwe abantu (SOCs), ebirikukoresibwa kukora ebintu bitari bimwe na bimwe. Ebirungo ebi eby’aheeru nari SOCs nibitwariramu polycyclic aromatic hydrocarbons (PAHs), emibazi y’okurwanisa obukooko, emibazi y’okurwanisa ebishaka, emibazi y’okurwanisa obuveera, erangi, emibazi, organophosphates, ebirikuzibira omuriro, ebirungo by’ebihangwa ebirikuhindukahinduka, n’ebindi. ebizibu ebirikushiisha aha bihangirwe ebitari bimwe na bimwe kurabira omu kuhindura aha mitwarize y‘omubiri n‘enkora y‘ekyanga (Petrie na bagyenzi be, 2015; Bernhardt na bagyenzi be, 2017; Sarkar na bagyenzi be, 2020). Ebirikushiisha bingi eby’omugaju biine amaani kandi ebirikushiisha aha bihangirwe bingi ebitaine kabi koona/ebicweka by’ebihangirwe ebiine amagara (nk’ebishaka, ebishaka bya Arctic/Antarctic, enyanja z’omu nshozi z’ahaiguru, ebishaka by’omu nyanja y’omunda, n’ebindi) (Jones 2010; Beyer et al. 2020; Nord20 et al. 2020; Nordborg). Okucondooza okuherize kukorwa aha by‘obuhangwa bw‘ensi (geomicrobiological matter) kworekire ngu okutaho ebintu by‘obuhangwa ebikozirwe abantu (nk‘ebintu ebirikushiisha eby‘omugaju) n‘ebirikurugamu aha itaka ry‘ebintu ebikozirwe abantu (eby‘obuhangwa ebyombekirwe) (nk‘ebicweka by‘obuhangwa n‘ebiijutsyo ebikozirwe omu mabaare g‘omuhendo, amabaare, embaaho n‘ebyoma) nikitunguura okusheenya kwabyo (Lidd2.G1). Ebikorwa by‘abantu nibibaasa kwongyera n‘okushiisha eby‘obuhangwa eby‘ebiijutsyo n‘ebyombeko kurabira omu kusheenya kw‘omuyaga n‘empindahinduka y‘obwire (Liu et al. 2020). Ebintu ebi ebirikushiisha nibikwatagana n’omuyaga gw’amaizi omu mwanya kandi bituura aha nkora, ekirikureetaho okusiisikara kw’ebintu omu mubiri n’omu by’emibazi. Okusheenyagura kw’ebintu ebiine amagara nikumanyirwa munonga nk’empindahinduka ezitarikwetengyesa omu ndeebeka n’emitwarize y’ebintu ebirikureetwa ebihangirwe ebiine amagara ebirikuteganisa okubiika (Pochon na Jaton, 1967). Ebindi bikorwa by‘obukooko obukye (okuhindura eby‘okurya) eby‘ebirungo ebi nibibaasa kukyendeeza aha buhame bw‘enkora, oburungi bw‘okurinda n‘omuhendo gw‘obuhangwa (Gadd, 2017; Liu et al., 2018). Aha rubaju orundi, omu mbeera ezimwe, okuhindura kw‘obukooko obukye n‘okugarukamu ebihangirwe ebi kishangirwe kiri eky‘omugasho nk‘oku birikukora ebishushani by‘amagara n‘ebindi bihimba by‘okwerinda ebirikukyendeeza aha mubaro gw‘okuvunda/okuvunda (Martino, 2016). Nahabwekyo, okukora enkora nungi z‘okurinda ebiijutsyo by‘amabaare, eby‘ekyoma n‘embaaho ebihikire eby‘obwire buraingwa nikyetengyesa okwetegyereza kurungi enkora enkuru eziri omu nkora egi. Wagyeragyeranisa n’enkora z’obuhangwa (enkora z’eitaka, omuriro gw’ebibira, okurugamu kw’enshozi, ebimera n’ebintu ebiine obukooko), emirimo y’abantu neerugamu okurekura kw’ebintu bingi ebirikwetwa polycyclic aromatic hydrocarbons (PAHs) n’ebindi bihingwa (OC) omu by’obuhangwa. PAHs nyingi ezirikukoresibwa omu by’obuhingi (emibazi y’okurwanisa obukooko n’emibazi y’okurwanisa obukooko nka DDT, atrazine, carbaryl, pentachlorophenol, n’ebindi), amakorero (amajuta agatari ga buriijo, ebishaka by’amajuta/ebishaju, obuveera oburikuruga omu mafuta g’okubanza, PCBs, obuveera oburikureeta obuveera, eby’okushemeza n’eby’okusheeshasheesha, ebintu by’okusheeshasheesha, ebintu by’okusheeshasheesha, eby’okusheeshasheesha. (ebirikuzibira eizooba, ebirikuzibira obukooko, ebirikubinga obukooko n’ebishaka ebirimu ebiriisa bingi) n’eby’okurwanisa (ebintu ebirikuturika nka 2,4,6-TNT) nibibaasa kuba biri eby’obuhangwa ebirikubaasa kukwata aha magara g’ensi (Srogi, 2007; Vamsee-Krishna na Phale, 2008; Petrie et al.5). Orukarara oru nirubaasa kwongyerwamu amaani kuhika aha birungo ebirikuruga omu mafuta g’emotoka (amajuta g’amajuta, ebirungo by’okusiiga, ebirungo by’okusiiga), ebirungo by’ebihangirwe ebiine oburemeezi bw’ahaiguru, n’amaizi g’amajuta (Amde et al., 2015). Ekipande 1 nikihandiika ebirungo by‘omubazi ebitari bimwe na bimwe n‘oku birikukoresibwa omu makorero gatari gamwe na gamwe. Omu myaka ehweire, ebirikuruga omu bantu eby’ebintu ebiine amagara ebirikuhindukahinduka, hamwe n’omuyaga ogurikwetwa carbon dioxide n’ebindi ebirikureetaho okukyendeeza aha bwire bw’omushana, bitandikire kweyongyera (Dvorak et al., 2017). Kwonka, ebirikuruga omu bantu nibikira munonga eby’obuhangwa. Okwongyera ahari ekyo, tukashanga ngu omubaro gwa SOCs nigugumaho omu myanya mingi y‘obuhangwa kandi zimanyirwe nk‘ebintu ebirikurugayo ebirikushiisha ebirikureetaho obubi aha bihangirwe ebiine amagara (ekishushani 1). Ebitongore by’obuhangwa nk’ekitongore ky’okurinda eby’obuhangwa ekya United States (USEPA) bikataho bingi aha bintu ebi ebirikushiisha omu runyiriri rwabyo ahabw’okugira ngu nibishiisha obutafaari bw’omubiri, obutwa bw’omubiri, obutwa bw’omubiri, n’obutwa bwa kansa. Nahabwekyo, ebiragiro by‘okusheenya ebigumire n‘enkora nungi z‘okuboneza/okuihaho kasasiro kuruga omu by‘obuhangwa ebiine obukooko nibyetengyesa. Emiringo etari emwe n‘emwe y‘okujanjaba eby‘omubiri n‘eby‘emibazi nk‘okujanjaba kw‘okwotsya, okujanjaba kw‘okwotsya kw‘okwotsya, okutaho omuyaga, okusheenya, okwotsya, n‘ebindi tibiine mugasho kandi nibitwara esente nyingi kandi nibireetaho ebirugiremu ebirikushiisha, obutwa kandi ebigumire kujanjaba. Ahabw‘okweyongyera kw‘okumanya eby‘obuhangwa omu nsi yoona, obukooko obukye oburikubaasa kusheenya obukooko obu n‘ebirikurugamu (nk‘ebiine halojeni, nitro, alkyl na/nari methyl) nibweyongyera kureetaho okufayo (Fennell na bagyenzi be, 2004; Haritash na bagyenzi be Kaushik, 200;200). abandi, 2020; abandi, 2020). Okukozesa obukooko obu obukye oburikwesimbaho ​​obw’omu ihanga bwonka nari omu buhangwa obutaine rubaju (amakolooni) ahabw’okuihaho obukooko oburikushiisha eby’omugaju bwine oburungi omu kureeba eby’obuhangwa, esente, okukora gye, okukora gye, n’okugumaho. Abacondoozi nabo bariyo nibacondooza aha kugaita enkora z‘obukooko obukye n‘emiringo y‘okugaruzaho amashanyarazi, nikwo kugira ngu enkora z‘amashanyarazi (BES), nk‘omuringo ogurikuraganisa ogw‘okujanjaba/okuihaho obukooko oburikushiisha (Huang et al., 2011). Tekinologiya ya BES etungire okweyongyera kw‘okuta omutima ahabw‘okukora gye, esente nkye, oburinzi bw‘eby‘obuhangwa, okukora omu bwire bw‘obutagatsi bw‘omu kishengye, ebintu ebirikuhikaana n‘ebintu ebiine amagara, n‘obushoboorozi bw‘okugaruzaho ebintu by‘omuhendo ebirikuruga omu nkora (nk‘amashanyarazi, amajuta, n‘emibazi) (Pant et al., 2012, Na2.0; Okwija kw’okukuratana kw’ebicweka by’omubiri ebirikukora munonga n’ebikwato/emiringo ya omics kuhaire obugaiga bw’amakuru masya aha nkora y’obuzaarwa, proteomics, na fluxomics y’okugarukamu kw’obukooko obutari bumwe na bumwe oburikusheenya. Okugaita ebikwato ebi n’enkora y’ebihangirwe by’omubiri kwongyeire kwongyera aha kwetegyereza kwaitu aha kutoorana n’okuboneza emihanda y’okuhindura eby’okurya ebigyendereirwe omu bihangirwe ebikye (nikwo kugira ngu, okukora eby’okurya) kubaasa kutunga okusheenya kw’ebihangirwe okuhikire kandi okuhikire. Okubaasa kukora enkora nungi z‘okugaruzaho eby‘amagara turikukoresa obukooko obuhikire oburikubaasa kutooranwa, twine kwetegyereza obushoboorozi bw‘eby‘amagara, obutashushana bw‘eby‘okurya, ebiri omu nkora y‘obuzaarwa, n‘eby‘obuhangwa (autoecology/synecology) by‘obukooko obukye.
Ekishushani 1. Enshonga n‘emihanda ya PAHs eziine molekyu nkye kurabira omu mbeera z‘obuhangwa zitari zimwe na zimwe n‘enshonga zitari zimwe na zimwe ezirikuteganisa ebihangirwe ebiine amagara. Enyiriri ezirimu obubonero nizijwekyera enkoragana ahagati y’ebintu by’obuhangwa.
Omu kucondooza oku, tugyerizeho kushoboorora omu bugufu amakuru agarikukwata aha kusheenyagura kwa PAHs ezoorobi nka naphthalene na naphthalenes ezihindwirwemu n‘ebicweka bya bacteria ebitari bimwe na bimwe ebirikushweka emihanda y‘okuhindura eby‘okurya n‘obutashushana, enzymes ezirikwejumba omu kusheenyagura, obutafaari bw‘omubiri/ebirimu n‘obutashushana, okugarukamu kw‘obutafaari bwa bioremediation n‘ebintu bitari bimwe na bimwe. Okwetegyereza emiringo y’eby’obuhangwa n’eby’obuhangwa nibiija kuhwera omu kumanya ebika by’abagyenyi ebihikire n’okwongyera aha nkora yaabyo ey’obuzaarwa ahabw’okuboneza gye eby’obuhangwa eby’ebintu nk’ebyo ebirikushiisha. Eki nikiija kuhwera omu kuteekateeka enkora z‘okutaho ebibiina by‘obukooko oburikureeta endwara z‘omu mwanya ahabw‘okuboneza gye eby‘amagara.
Okubaho kw‘omubaro muhango gw‘ebintu by‘obutwa n‘eby‘akabi (ebirikuhikiiriza ekiragiro kya Huckel 4n + 2π electrons, n = 1, 2, 3, ...) nikireetaho akabi k‘amaani aha bintu by‘obuhangwa ebitari bimwe na bimwe nk‘omuyaga, eitaka, ebisigarira, n‘eitaka ry‘ahaiguru, eitaka70). Ebirungo ebi biine empeta za benzene emwe (monocyclic) nari empeta za benzene nyingi (polycyclic) ezitebeekanisiibwe omu muringo gw’omuringo gumwe, ogw’enkokora nari ogw’ekibumbe kandi nizooreka okuhama (okuhama/okutahama) omu by’obuhangwa ahabw’amaani g’okuhurira agatari marungi maingi n’obutakora (inertness), ekirikubaasa kushoboororwa ahabw’embeera yaabyo ey’okukyendeera n’okutagira amaizi. Empeta y’omugaju ku erikweyongyera kuhindurwa guruupu za methyl (-CH3), carboxyl (-COOH), hydroxyl (-OH), nari sulfonate (-HSO3), neeguma neegumaho, eine akakwate k’amaani n’ebicweka by’omubiri ebihango, kandi neeteerana omu nkora z’ebihangirwe (Seo et al., al2.09; Ebimwe aha bihingwa ebiine oburemeezi bukye (LMWAHs), nk‘eby‘okurya ebirimu ebiriisa by‘omubiri n‘ebirikurugamu [eby‘okurya ebirimu ebiriisa by‘omubiri, asidi y‘omubiri, asidi y‘omubiri, ebiriisa by‘omubiri, na 1-naphthyl N-methylcarbamate (carbaryl)], biteirwe omu runyiriri rw‘ebintu ebirikwebembeza eby‘okurya ebirimu ebiriisa bya Provitron the US . obutwa bw‘omubiri, oburikuhindura omubiri, na/nari oburikureetaho obukooko bwa kansa (Cerniglia, 1984). Okurekura ekibiina eki kya NM-PAHs omu by’obuhangwa nikibaasa kurugamu okuteerana kw’ebintu ebiine amagara aha rurengo rwona orw’eby’okurya, obwo nikikwata aha magara g’ebintu ebiine amagara (Binkova na bagyenzi be, 2000; Srogi, 2007; Quinn na bagyenzi be, 2009).
Enshonga n’emihanda ya PAHs kuza omu bihangirwe ebiine amagara nibikira kurabira omu kufuruka n’okukoragana ahagati y’ebicweka by’eby’obuhangwa ebitarikushushana nk’itaka, amaizi g’ahansi y’itaka, amaizi g’ahaiguru, ebirimwa n’omu mwanya (Arey na Atkinson, 2003). Ekishushani 1 nikyoreka enkoragana n‘okujanjaara kwa PAHs z‘oburemeezi bukye zitari zimwe na zimwe omu by‘obuhangwa n‘emihanda yaazo kuhika aha kumanyisibwa kw‘ebintu ebiine amagara/abantu. PAHs niziteebwa aha itaka ahabw‘okushiisha empeho kandi kurabira omu kufuruka (drift) kw‘ebintu ebirikuruga omu motoka, ebiri omu makorero (okuhindura amakara, okwotsya n‘okukora coke) n‘okubiteeka. Emirimo y’amakorero nk’okukora emyenda y’obuhangwa, erangi n’erangi; okurinda enku; okukora aha mipiira; emirimo y’okukora sementi; okukora emibazi y’okurwanisa obukooko; n’okukozesa eby’obuhingi n’oburiisa n’enshonga nkuru z’okutunga PAHs omu nkora z’ahansi n’omu maizi (Bamforth na Singleton, 2005; Wick na bagyenzi be, 2011). Okucondooza kworekire ngu eitaka ry‘omu byaro n‘omu ndembo, haihi n‘enguuto empango, n‘omu ndembo empango niribaasa kukwatwaho munonga polycyclic aromatic hydrocarbons (PAHs) ahabw‘okushohoza ebiriisa kuruga omu bitongore by‘amashanyarazi, okuhemba kw‘omu maka, emigugu y‘omuyaga n‘eby‘enguuto, n‘emirimo y‘okwombeka (Suman et al20,1). (2008) bakooreka ngu PAHs omu itaka haihi n’enguuto omuri New Orleans, Louisiana, USA zikaba ziri ahaiguru nka 7189 μg/kg, obwo omu mwanya ogurikwiguka, zikaba ziri 2404 μg/kg zonka. Omu muringo nigwo gumwe, ebiri omu PAH ebirikuhika 300 μg/kg bikagambwaho omu myanya eri haihi n’emyanya y’okukoramu amakara omu ndembo nyingi eza America (Kanaly na Harayama, 2000; Bamforth na Singleton, 2005). Eitaka kuruga omu ndembo zitari zimwe na zimwe eza Buhindi nka Delhi (Sharma na bagyenzi be, 2008), Agra (Dubey na bagyenzi be, 2014), Mumbai (Kulkarni na Venkataraman, 2000) na Visakhapatnam (Kulkarni na bagyenzi be, 2014) rikagambwa kuba ririmu PAH nyingi. Ebirungo by’omugaju nibikira kukwatwa aha bicweka by’itaka, ebintu ebiine amagara n’ebintu by’eibumba, n’ahabw’ekyo nibihinduka ebirungo bikuru by’okusheenya kaboni omu by’obuhangwa (Srogi, 2007; Peng et al., 2008). Enshonga nkuru ezirikurugamu PAHs omu by‘obuhangwa bw‘omu maizi n‘enjura (enjura y‘omushana/eyomire n‘omuyaga gw‘amaizi), okusheesheka kw‘omu ndembo, okusheesheka kw‘amaizi g‘ebishaka, okugaruka kw‘amaizi g‘ahansi y‘itaka n‘ebindi (Srogi, 2007). Nikiteekateekwaho ngu ebicweka nka 80% bya PAHs omu by’obuhangwa bw’omu nyanja nibiruga omu kugwa kw’enjura, okusheenya, n’okusheenya kasasiro (Motelay-Massei na bagyenzi be, 2006; Srogi, 2007). Ebicweka bya PAHs bingi omu maizi g‘ahaiguru nari omu myanya y‘okusheenya kasasiro egumire nibihendera bisheeshekire omu maizi g‘ahansi y‘itaka, ekirikureetaho akabi k‘amaani aha magara g‘abantu ahabw‘okuba abantu abarikurenga 70% omu bukiizi-bwa-bumosho n‘omu bukiizi-bwa-bumosho bwa Asia nibanywa amaizi g‘ahansi y‘itaka (Duttagupta et al., 2019). Okucondooza okukozirwe Duttagupta na bagyenzi be. (2020) y’okucondooza kw’omugyera (32) n’amaizi g’ahansi y’itaka (235) kuruga West Bengal, India, bakashanga ngu okutebereza 53% b’abatuuragye b’omu ndembo na 44% b’abatuuragye b’omu byaro (abatuuragye miriyoni 20 boona hamwe) nibabaasa kuba baine obuzibu bw’okutunga ebiriisa bya naphthalene (4.9–10.s na μL/10.6ts). Enkora z‘okukoresa eitaka zitari zimwe na zimwe n‘okwongyera aha kushohora kw‘amaizi g‘ahansi y‘itaka nibitwarwa nk‘ebintu ebikuru ebirikutegyeka entambura y‘okutegyeka (advection) y‘oburemeezi bukye bwa PAHs omu itaka ry‘ahansi. Amaizi g’eby’obuhingi n’oburiisa, amaizi g’ebishaka agarikuruga omu munisiparite n’amakorero, n’amaizi g’ebishaka agagumire/akasasiro bikashangwa ngu nibikwatwaho PAHs omu bifunjo by’emigyera n’ebishaka ebiri ahansi y’itaka. Enjura y’omu mwanya neeyongyera kwongyera aha kusheeshasheesha kwa PAH. Ebicweka bya PAHs bingi n’ebirikurugamu alkyl (51 omu bwijwire) bikagambwaho omu migyera/ebicweka by’amaizi omu nsi yoona, nk’omugyera Fraser, omugyera Louan, omugyera Denso, omugyera Missouri, omugyera Anacostia, omugyera Ebro, n’omugyera Delaware (Yunker et al., 2002; Motelay-al.2,0). 2010; Amoako n’abandi, 2011; Omu bihingwa by’omugyera Ganges, naphthalene na phenanthrene bikashangwa biri ebikuru munonga (bikashangirwe omu 70% by’eby’okureeberaho) (Duttagupta et al., 2019). Ekindi, okucondooza kworekire ngu okutaho klorini omu maizi g‘okunywa nikibaasa kureetera okuhangaho obutwa bwingi oburimu oxygen n‘obutwa bwa PAHs (Manoli na Samara, 1999). PAHs nizirundaana omu bihingwa, ebijuma n’emboga ahabw’okutwarwa ebimera kuruga omu itaka eririmu obukooko, amaizi g’ahansi y’itaka n’enjura (Fismes et al., 2002). Ebihangirwe bingi eby’omu maizi nk’eby’enyanja, ebihimba, ebihimba n’ebihimba nibikwatwa obukooko bwa PAHs kurabira omu kurya eby’okurya n’amaizi g’enyanja ebiine obukooko obu, hamwe n’okurabira omu nyama n’oruhu (Mackay na Fraser, 2000). Emiringo y‘okuteeka/okukora nk‘okuteeka, okwotsya, okufuka, okusiika, okwomya, okuteeka n‘okuteeka aha makara nayo neebaasa kureetera PAHs nyingi omu by‘okurya. Eki nikirugiirira munonga aha kutoorana eby‘okukoresa omu kunywa etaabe, ebiri omu phenolic/aromatic hydrocarbon, omuringo gw‘okuteeka, ekika ky‘ekyoma ky‘okuhemba, obutagatsi oburimu, okutunga oxygen n‘obutagatsi bw‘okwotsya (Guillén et al., 2000; Gomes et al., 2013). Ebirungo by‘amaizi ebirimu ebiriisa bingi (PAHs) nabyo bikashangwa omu mate omu nkora zitari zimwe na zimwe (0.75–2.1 mg/L) (Girelli et al., 2014). Okuteerana kwa PAHs ezi omu by‘okurya nakyo nikirugiirira aha mitwarize y‘eby‘okurya, obwo obutwa bwazo burikukwatagana n‘emirimo y‘omubiri, emirimo y‘okuhindura eby‘okurya, okunywa, okujanjaara n‘okujanjaara kw‘omubiri (Mechini et al., 2011).
Obutwa n‘akabi akarikuruga omu bihingwa ebirimu ebiriisa bingi (PAHs) bikamanyirwa kumara obwire buraingwa (Cherniglia, 1984). Ebirungo by‘omubiri ebiine oburemeezi bukye (LMW-PAHs) (empeta ibiri kuhika ahari ishatu) nibibaasa kukwatiraine n‘ebicweka bikuru ebitari bimwe na bimwe nka DNA, RNA na puroteyini kandi nibireetaho obukooko bwa kansa (Santarelli et al., 2008). Ahabw’okugira ngu nizikunda amaizi, nizitaanisibwa n’ebishaju. Omu bantu, obutafaari oburikwetwa cytochrome P450 monooxygenases nibuhindura PAHs kuba epoxide, ezimwe aharizo nizikora munonga (nk‘eky‘okureeberaho, epoxide ya baediol) kandi nizibaasa kureetera obutafaari obuhikire kuhinduka obutafaari obubi (Marston et al., 2001). Okwongyera ahari ekyo, ebirugire omu kuhindura kwa PAHs nka quinones, phenols, epoxides, diols, n’ebindi nibikira obutwa bw’omubiri kukira ebirungo by’omuzaire. PAH ezimwe n‘ebintu byazo ebiri ahagati y‘eby‘okurya nibibaasa kukwata aha nkora y‘okuhindura eby‘okurya n‘enzigye zitari zimwe na zimwe omu kuhindura eby‘okurya, obwo nibikwata kubi okukura, enkora y‘obutafaari bw‘omubiri obw‘ahagati, enkora y‘okuzaara n‘enkora y‘okurwanisa endwara (Swetha na Phale, 2005; Vamsee-Krishna na bagyenzi be, 2006; Oostingh na bagyenzi be.,). Obwire bukye bw‘okukoresa PAHs z‘oburemeezi bukye kigambirweho ngu nikireetaho okuremwa kukora gye kw‘amahaha n‘okusheeshasheesha kw‘eshagama omu barwaire b‘ebihaha n‘okwongyera aha kabi k‘okukwatwa ekookoro y‘oruhu, amahaha, omu nkari n‘omu nda (Olsson et al., 2010; Diggs et al., 2011). Okucondooza aha nyamaishwa nakwo kworekire ngu okukwatwa PAH nikibaasa kugira ebizibu aha mirimo y‘okuzaara n‘okukura kandi nikibaasa kureetera okusharara kw‘amaisho, okushiisha ensigo n‘ebihaha, n‘okusharara kw‘omubiri. Ebintu bitari bimwe na bimwe eby’okuhindura eby’obuhangwa bya PAH nka diols, epoxides, quinones na radicals z’obuntu (cations) byorekwa ngu nibikora ebirikureetaho DNA. Ebirungo ebigumire nibyorekwa ngu nibihindura eby’okukoresa eby’okugarukamu DNA, obwo ebirungo ebitagumire birikubaasa kusheenya DNA (okukira munonga kuza omu adenine kandi obumwe kuza omu guanine); byombi nibibaasa kureetaho enshobi ezirikureetaho okuhinduka kw’ebintu (Schweigert na bagyenzi be 2001). Okwongyera ahari ekyo, quinones (benzo-/pan-) nizibaasa kureetaho ebika bya oxygen ebirikukora (ROS), ekirikureetaho okushiisha kw‘okufa ahari DNA n‘ebindi bihingwa ebikuru, obwo nibikwata aha mirimo/okubaasa kw‘ebicweka by‘omubiri (Ewa na Danuta 2017). Okumara obwire buraingwa orikukoresa ebiriisa bikye ebya pyrene, biphenyl na naphthalene kigambirweho ngu nikireetera ekookoro omu nyamaishwa ezirikugyezibwa (Diggs et al. 2012). Ahabw‘obutwa bwazo oburikwita, okuboneza/okuihaho PAHs ezi kuruga omu myanya erikukwatwaho/eine obuzibu n‘eky‘okubanza.
Emiringo etari emwe n‘emwe ey‘omubiri n‘eby‘emibazi ekoresiibwe kwihaho PAHs kuruga omu myanya/embeera ezirimu obukooko. Enkora nk’okwotsya, okukyendeeza aha chlorine, UV oxidation, fixation, n’okushohoza ebiriisa biine oburemeezi bwingi, harimu okukora ebintu ebirikuruga omu nkora ebirimu obutwa, okugumizamu kw’enkora, enshonga z’obukuumi n’okutegyeka, okukora gye kukye, n’okutwara esente nyingi. Kwonka, okusheenyagura kw’ebintu ebikye (ebirikwetwa bioremediation) n’omuringo ogundi ogurikuraganisa ogurikutwariramu okukoresa obukooko obukye omu muringo gw’obuhangwa obushemeire nari amahanga. Wagyeragyeranisa n‘emiringo y‘okukoresa eby‘omubiri n‘eby‘emibazi, omuringo ogu nigukora gye aha by‘obuhangwa, tigurikuteganisa, tigurikutwara sente nyingi, kandi nigubaasa kugumaho. Okugaruzaho eby‘obuhangwa nikubaasa kukorwa omu mwanya ogurikukwatwaho (omu mwanya) nari omu mwanya ogutebeekanisiibwe omu muringo gw‘omutaano (ex situ) n‘ahabw‘ekyo nigutwarwa nk‘omuringo gw‘okugaruzaho ogurikugumizamu kukira emiringo y‘obuhangwa ey‘omubiri n‘eby‘emibazi (Juhasz na Naidu, 2000; Andreoni na Gianfreda et al2007; al Megha,10). 2020; Sarkar n’abandi, 2020).
Okwetegyereza amatembezo g‘okuhindura eby‘okurya by‘obukooko obukye agarikwejumba omu kusheenyagura ebirikushiisha ebiriisa by‘omugaju biine ebirugiremu bingi munonga omu bya sayansi n‘eby‘entaasya aha kugumaho kw‘eby‘obuhangwa n‘eby‘obuhangwa. Ekicweka kya kaboni (C) ekirikuteberezibwa kuba kiri 2.1×1018 grams nikibiikwa omu bihingwa n’ebintu ebiine amagara (nikwo kugira ngu, amajuta, gaasi y’obuhangwa, n’amakara, nikwo kugira ngu, amajuta g’ebishaka) omu nsi yoona, ekirikureetaho omugasho muhango omu nkora ya kaboni omu nsi yoona. Kwonka, amakorero g’ahonaaho, okushohoza amajuta g’ebintu ebiine amagara, n’emirimo y’abantu nibimaraho ebibiiko ebi eby’omu itaka, nibirekura ebirikwingana 5.5×1015 g bya kaboni y’ebihangwa (nk’ebintu ebirikushiisha) omu mwanya buri mwaka (Gonzalez-Gaya et al., 2019). Ebingi ahari kaboni egi neetaaha omu by’obuhangwa by’omu itaka n’omu nyanja kurabira omu kusheenya, okutwara, n’okusheenya. Okwongyera ahari ekyo, ebintu bisya ebikozirwe abantu ebirikuruga omu mafuta g’ebishaka, nk’ebiveera, ebiveera n’ebirikuhamya obuveera (phthalates na isomers zaabyo), nibishiisha munonga eby’obuhangwa by’omu nyanja, eitaka n’eby’omu maizi n’ebihangirwe byabyo, obwo nibyeyongyera akabi k’embeera y’obwire omu nsi yoona. Ebika bitari bimwe na bimwe eby’obuveera obukye, obuveera obukye, ebicweka by’obuveera n’ebintu byabyo eby’obutwa ebirikuruga omu polyethylene terephthalate (PET) biteeraine omu nyanja ya Pacific ahagati ya North America na Southeast Asia, byakora “Ekicweka kihango kya kasasiro ya Pacific”, ebirikushiisha amagara g’omu nyanja (Newell et al.20, 20). Okucondooza kwa sayansi kworekire ngu tikirikubaasika kwihaho obukooko/obukooko nk’obwo omu miringo yoona ey’omubiri nari ey’eby’emibazi. Omu nkora egi, obukooko obukye oburikukirayo omugasho n‘obwo oburikubaasa kuhindura ebiriisa ebirikushiisha omu muringo gwa oxidative bikahinduka carbon dioxide, amaani g‘eby‘obuhangwa n‘ebindi ebitari by‘obutwa ebirikuhendera bitaahire omu miringo endiijo y‘okuhindura ebiriisa (H, O, N, S, P, Fe, n‘ebindi). Nahabwekyo, okwetegyereza eby‘obuhangwa bw‘ebintu ebikye eby‘okusheeshasheesha kw‘eby‘obuhangwa n‘okubitegyeka eby‘obuhangwa ni kikuru munonga omu kucondooza aha nkora ya kaboni y‘ebintu ebikye, embariirira ya kaboni yoona n‘akabi k‘embeera y‘obwire omu biro by‘omumaisho. Ahabw’okwetenga kw’ahonaaho okw’okuihaho ebirungo nk’ebyo omu by’obuhangwa, amakorero gatari gamwe na gamwe ag’eby’obuhangwa agarikuta omutima aha tekinologiya eshemeire gakabaho. Ebindi, okuha omuhendo kasasiro y‘amakorero/emibazi y‘okusheeshasheesha erikuteeranirwa omu nkora y‘eby‘obuhangwa (nikwo kugira ngu enkora y‘okusheeshasheesha kuza omu by‘obugaiga) neetwarwa nk‘emwe aha nshonga z‘eby‘entasya erikwetoorora n‘ebigyendererwa by‘entunguuka etarikuhwaho (Close et al., 2012). Nahabwekyo, okwetegyereza ebirikukwata aha nkora y‘okuhindura eby‘okurya, enzymatic n‘eby‘obuzaarwa bw‘ebintu ebi ebirikubaasa kusheenyagurika n‘eky‘omugasho munonga omu kwihaho n‘okuboneza gye ebirikushiisha eby‘omubiri nk‘ebyo.
Omu bintu bingi ebirikushiisha ebiriisa, nituta omutima munonga aha PAHs eziine oburemeezi bukye nka naphthalene na naphthalenes ezirikuhindurwa. Ebirungo ebi n’ebicweka bikuru eby’amajuta agarikuruga omu mafuta, erangi z’emyenda, ebintu ebirikukoresibwa abantu, emibazi y’okurwanisa obukooko (ebishaka n’ebirikubinga ebikooko), ebirikukora obuveera n’ebirikukora ebiriisa n’ahabw’ekyo nibijanjaara munonga omu by’obuhangwa bingi (Preuss et al., 2003). Amakuru agahererukireyo nigoreka okuteerana kw’ebicweka bya naphthalene omu itaka ry’omu itaka, amaizi g’ahansi y’itaka n’ahansi y’itaka, emyanya ya vadose n’ebishaka by’emigyera, ekirikumanyisa okuteerana kwayo omu by’obuhangwa (Duttagupta et al., 2019, 2020). Ekipande kya 2 nikifunza aha mitwarize y‘omubiri n‘eby‘obuhangwa, okukoresibwa n‘ebirikuruga omu magara g‘omubazi gwa naphthalene n‘ebirikurugamu. Wagyeragyeranisa n’ebindi bihingwa ebiine oburemeezi bw’amaani, naphthalene n’ebirikurugamu nibikunda amaizi makye, nibikira kunywa amaizi kandi nibijanjaara munonga omu by’obuhangwa, n’ahabw’ekyo nibikira kukoresibwa nk’eby’okureeberaho by’okwega aha nkora y’okuhindura eby’okurya, eby’obuzaarwa n’okuhindura kw’eby’okurya bya PAHs. Omubaro muhango gw’obukooko obukye nibubaasa kuhindura naphthalene n’ebirikurugamu, kandi amakuru marungi nigashangwa aha mihanda yaabo y’okuhindura, enzymes n’ebintu ebirikutegyeka (Mallick na bagyenzi be, 2011; Phale na bagyenzi be, 2019, 2020). Okwongyera ahari ekyo, naphthalene n’ebirikurugamu bitebeekanisiibwe nk’ebintu by’okureeberaho eby’okushwijuma okushiisha eby’obuhangwa ahabw’obungi bwabyo bwingi n’okubaasa kutunga ebiriisa. Ekitongore ky‘okurinda eby‘obuhangwa ekya America nikiteekateeka ngu omubaro gwa naphthalene ogwagati ni 5.19 μg ahari cubic meter kuruga omu mwika gw‘etaabe, okukira munonga kuruga omu kwotsya okutahikire, na 7.8 kuhika 46 μg kuruga omu mwika gw‘aha rubaju, obwo okukwatwa creosote na naphthalene toP0us eri 1,000. abandi 2003). Naphthalene namunonga ekashangwa eine obutwa bw‘okuhuuta oburikurugiirira aha kika, ekicweka, n‘obuhangwa bw‘abantu n‘okureetaho obukooko bwa kansa. Okurugirira aha kucondooza aha nyamaishwa, ekitongore ky‘ensi yoona eky‘okucondooza aha ndwara ya kansa (IARC) kikata omu kicweka kya naphthalene nk‘ekintu ekirikubaasa kureetaho endwara ya kansa y‘abantu (Group 2B)1. Okwemanyiza ebiriisa bya naphthalenes ebihindwirwemu, okukira munonga orikubihuuta nari okubinywa omu kanwa (omu kanwa), nikireetaho okuhutaara kw‘ebicweka by‘amahaha kandi kyongyera aha kukwatwa ebizimba by‘amahaha omu mbeba n‘embeba (National Toxicology Program 2). Ebizibu by‘amaani harimu okuhurira kubi, okusheeshasheesha, okushaasha omunda, okusheeshasheesha, okushaasha omutwe, okushoberwa, okusheeshasheesha kwingi, omushwija, okuteera omutima, n‘ebindi Aha rubaju orundi, omubazi gw‘okurwanisa obukooko oburikureeta obuhuta bw‘amaani ogwa carbaryl (1-naphthyl N-methylcarbamate in toxibte, toxiy, abantu kandi kyorekwa ngu nikizibira okusheeshasheesha okurikureetaho okusharara (Smulders na bagyenzi be, 2003; Bulen na Distel, 2011). Nahabwekyo, okwetegyereza emiringo y‘okusheenyagura obukooko obukye, okutegyeka eby‘obuzaarwa, okugarukamu kw‘enzigye n‘obutafaari ni kikuru munonga omu kuhangaho enkora z‘okugaruzaho obukooko obukye omu myanya erimu obukooko.
Ekipande 2. Amakuru agarikukwata aha mitwarize y‘omubiri n‘eby‘obuhangwa, enkozesa, emiringo y‘okumanyisa n‘endwara ezirikukwatagana na naphthalene n‘ebirikurugamu.
Omu myanya erimu obukooko, obukooko oburimu amaizi n‘obukooko oburikureeta amaizi nibubaasa kureetera obutafaari bw‘omubiri obutari bumwe na bumwe aha bihangirwe ebikye (ekyanga), nk‘empindahinduka omu nkora y‘okusheeshasheesha, okutambura kw‘omubiri, okuzimba kw‘amaizi g‘omubiri, okutabura okutwarwa kw‘amaani (electron membrane transportated a proteina chain/ (Sikkema n’abandi, 1995). Okwongyera ahari ekyo, ebimwe ebiri ahagati y’ebintu ebirikusheesheka nk’ebiriisa bya katekoli na quinones nibireetaho ebika bya oxygen ebirikukora (ROS) kandi bikora ebirungo ebirimu DNA na puroteyini (Penning et al., 1999). Nahabwekyo, obungi bw’ebirungo nk’ebi omu nkora y’eby’obuhangwa nibureetaho okugyemeserezibwa kw’okutoorana aha byaro by’obukooko obukye kubaasa kuba ebihingwa ebirungi aha mitwe y’omubiri etari emwe n’emwe, obariiremu okutwara/okutwara, okuhindura omunda y’obutafaari, okushoroora/okukozesa, n’okutaho ebicweka.
Okucondooza okwakozirwe omu purojekiti ya Ribosomal Database Project-II (RDP-II) kukashohoza ngu ebika bya bacteria 926 bikataanisibwa kuruga omu by’amakuru nari omu buhangwa bw’okugaita oburimu obukooko bwa naphthalene nari ebirikurugamu. Ekibiina kya Proteobacteria kikaba kiine omubaro gw’abajwekyerwa baingi (n = 755), kyakuratirwa obukooko oburikwetwa Firmicutes (52), obukooko oburikwetwa Firmicutes (43), obukooko oburikwetwa Actinobacteria (39), obukooko oburikwetwa Tenericutes (10), na obukooko obutarikushoroorwa (8) (ekishushani 2). Abajwekyerwa ba γ-Proteobacteria (Pseudomonadales na Xanthomonadales) bakakirayo omu guruupu zoona ezitari za Gram eziine G+C nyingi (54%), kandi Clostridiales na Bacillales (30%) zikaba ziri guruupu eziine Gram eziine G+C nkye. Pseudomonas (omubaro gw’ahaiguru, ebika 338) bikagambwa kuba nibibaasa kusheenya naphthalene n’ebintu byayo ebirikuruga omu methyl omu by’obuhangwa ebitari bimwe na bimwe ebiine obukooko (amakara, amajuta, amajuta g’ebishaka, ebishaka, amajuta agarikusheesheka, amaizi g’ebishaka omu nkora y’ebishaka n’ebicweka by’ebishaka) nk’oku e, amaizi g’ahansi y’itaka) (Ekishushani 2). Ekindi, okucondooza aha kugaita n’okucondooza kwa metagenomic okwa bimwe aha bicweka ebi kukashohoza ngu ebika bya Legionella na Clostridium ebitarikukura nibibaasa kugira obushoboorozi bw’okusheenya, ekirikworeka ekyetengo ky’okuhinga obukooko obu okwega emihanda mirungi n’okuhindura eby’okurya.
Ekishushani 2. Okutaana kw’eby’obuhangwa n’okujanjaara kw’eby’obuhangwa kw’abajwekyerwa ba bacteria omu myanya erimu obutwa bwa naphthalene n’ebirikuruga omu naphthalene.
Omuri obukooko obukye obutari bumwe na bumwe oburikushiisha amaizi g’omubazi, obungi nibubaasa kusheenya naphthalene nk’entandikwa yonka eya kaboni n’amaani. Okukuratana kw’ebintu ebirikwejumba omu kuhindura ebiriisa bya naphthalene kushobooroirwe ahari Pseudomonas sp. (ebika: NCIB 9816-4, G7, AK-5, PMD-1 na CSV86), ebizimba by’omubiri ebirikwetwa PC20 n’ebindi bihingwa (ND6 na AS1) (Mahajan n’abandi, 1994; Resnick na bagyenzi be, An09; al., 2003; Sota na bagyenzi be, 2006; okuhindura naftalini kuba cis-naftalinidiyoli (Ekishushani 3 Cis-dihydrodiol neehindurwa kuba 1,2-dihidroksinaftalini ahabw’ekintu ekirikusharaho empeta, 1,2-dihidroksinaftalini-dioksijenazi (12DHNDO), 2). 2-haidrokisikromeni-2-karboksiliki asidi y‘enzigye neereetaho trans-o-haidrokisibenzilidenepyruvate, erikusharaho hydratase aldolase kuza omu salicylic aldehyde na pyruvate Asidi y‘omubiri ey‘okubanza ekaruga omu nkora ya kaboni ey‘ahagati. Salicylaldehyde erikwegamira ahari NAD+ neehindura salicylaldehyde kuba salicyl acid omu nkora y‘okuhindura eby‘okurya omu mubiri aha rurengo oru nikyetwa “omuhanda gw‘ahaiguru” gw‘okusheenyagura naphthalene Omuhanda ogu nigukira kubaho omu bacteria ezirikusheenyagura naphthalene ezirikukira obwingi omu, okusheenyagura kwa naftalini nikutandikirwaho naftalini 2,3-dioxygenase kubaasa kuhanga 2,3-dihaidrokisinaftalini (Annweiler et al., 2000).
Ekishushani 3. Emihanda y‘okusheenyagura ebiriisa by‘omubiri, ebiriisa by‘omubiri, ebiriisa by‘omubiri, na carbaryl. Enamba ezirikwetoorora nizijwekyera enzymes ezirikukora aha kuhindura naphthalene n’ebirikurugamu omu muringo ogurikukuratana kuba ebintu ebirikukurataho. 1 — omubazi gw’okusheeshasheesha (NDO); 2, cis-dihaidrodiyoli erikukyendeeza amaizi; 3, 1,2-dihayidrokisinaftalini ebiriisa by’omubiri; 4, 2-haidrokisikromeni-2-kabokisiliki asidi isomeraasi; 5, ekirikuhindura amaizi g’omubiri; 6, ekirikureeta amaizi omu mubiri; 7, salisilaiti 1-haidrokisilaasi; 8, ebiriisa ebiri omu mubiri (C23DO); 9, 2-haidrokisimukonati semialdehide dehaidrojenaasi; 10, 2-oksopenti-4-enoate y’amaizi; 11, 4-haidrokisi-2-oksopentanoate aldolase; 12, okukyendeeza aha maizi g’omubiri; 13, ebiriisa by’omubiri (C12DO); 14, ekirungo ky’omubiri; 15, omukoro gw’okukyebera; 16, β-ketoadipatenolaktoni ey’amaizi; 17, β-ketoadipate erikuhindura ebiri omu mubiri; 18, β-ekirungo ky’omubiri-CoA; 19, okusheeshasheesha-CoA: okusheeshasheesha-CoA okusheeshasheesha; 20, salisilaiti 5-haidrokisilaasi; 21 – ebiriisa by’omubiri (GDO); 22, omubazi gw’okukyebera; 23, omubazi gw’okusheeshasheesha; 24, ebiriisa by’omubiri (NDO); 25, ekirikureeta amaizi g’omubiri; 26, omubazi gw’okusheeshasheesha; 27, 3-omubazi gw’okukyebera asidi; 28, ebiriisa ebiri omu mubiri; 29, ekirungo ky’amaizi (CH); 30, 1-naftol-2-haidrokisilaasi.
Okurugirira aha kihangirwe n‘oku kiri omu nkora y‘obuzaarwa bwakyo, salisiliki asidi erikurugamu neeyongyera kuhindurwa kurabira omu muhanda gwa katekoli orikukoresa salisili 1-hidroksilase (S1H) nari kurabira omu muhanda gwa gentisate orikukoresa salisili 5-hidroksilasi (S5H) (ekishushani 3). Ahabw‘okugira ngu salicylic acid niyo nshonga nkuru omu kuhindura ebiriisa bya naphthalene (omuhanda gw‘ahaiguru), amatembezo kuruga ahari salicylic acid kuza aha nkora ya TCA nigakira kwetwa omuhanda gw‘ahansi, kandi ebiriisa nibitebeekanisibwa omu operon emwe. Nikimanyirwa kureeba ngu obutafaari oburi omu muhanda gwa ruguru operon (nah) n‘omuhanda gwa hansi operon (sal) nibutegyekwa enshonga z‘okutegyeka ezirikushushana; nk‘eky‘okureeberaho, NahR na salicylic acid nibikora nk‘ebirikureetaho, ebirikubaasisa operons zombi kuhindura kimwe ebiriisa by‘omubiri (Phale et al., 2019, 2020).
Okwongyera ahari ekyo, katekoli neesharaho omu muringo gw’enzindo ekahinduka 2-haidrokisimukonati semialdehyde kurabira omu muhanda gwa meta ogurikukoresibwa katekoli 2,3-dioxygenase (C23DO) (Yen et al., 1988) kandi eyongyera kuhindurwa 2-haidrokisimukonati semialdehide asidi2,4 kuhinduka amaizi. 2-haidrokisipenti-2,4-dienoate bwanyima neehindurwa pyruvate na asetaldehaidi ahabw’ekirungo ky’amaizi (2-oksopenti-4-enoate haidratasi) n’ekirungo ky’amaizi (aldolase) reero bwanyima etaaha omu muhanda gwa kaboni ogwa rwagati (ekishushani 3). Ebindi, katekoli neesharaho omu muringo gw‘enzindo kuba cis,cis-muconate kurabira omu muhanda gwa ortho ahabwa katekoli 1,2-oxygenase (C12DO). Omubazi gw’okusheeshasheesha niguhindura cis,cis-muconate kuba 3-oxoadipate, ogurikutaaha omu muhanda gwa kaboni ogwagati kurabira omu succinyl-CoA na acetyl-CoA (Nozaki et al., 1968) (Nozaki et al., 1968) (Ekishushani3).
Omu muhanda gw’okusheeshasheesha (2,5-dihydroxybenzoate), empeta y’okusheeshasheesha neesharaho ekiriisa kya 1,2-dioxygenase (GDO) kubaasa kuhangaho maleylpyruvate. Ekintu eki nikibaasa kuhindurwa amaizi butoosha kihinduke ekirungo kya pyruvate na malate, nari nikibaasa kuhindurwa isomerize kibe ekirungo kya fumarylpyruvate, ekirikubaasa kuhindurwa amaizi kihinduke ekirungo kya pyruvate na malate (Larkin na Day, 1986). Okutoorana omuhanda ogundi kukyebeirwe omu bacteria bombi abatari ba Gram n’abaine Gram aha rurengo rw’eby’amagara n’eby’obuzaarwa (Morawski na bagyenzi be, 1997; Whyte na bagyenzi be, 1997). Obukooko obutari bwa Gram (Pseudomonas) nibukunda kukoresa salisiliki asidi, erikureetaho okuhinduka kw’ebiriisa omu mubiri, bikagihindura katekoli barikukoresa salisiliiti 1-haidroksilaasi (Gibson na Subramanian, 1984). Aha rubaju orundi, omu bacteria ezirimu Gram (Rhodococcus), salicylate 5-hydroxylase neehindura asidi y’omubiri kuba asidi y’omubiri, obwo asidi y’omubiri etaine ki erikukora aha kuhandiika kw’ebicweka by’omubiri ebirikukora nk’ebiriisa (Grund et al., 1992) (Ekishushani 3).
Kigambirwe ngu ebika by’ebinyonyi nka Pseudomonas CSV86, Oceanobacterium NCE312, Marinhomonas naphthotrophicus, Sphingomonas paucimobilis 2322, Vibrio cyclotrophus, Pseudomonas fluorescens LP6a, Pseudomonas degrograde hamwe na . ebiriisa by’omubiri ebiri omu nkora y’okuteerana (Dean-Raymond na Bartha, 1975; Cane na Williams, 1982; Mahajan n’abandi, 1994; Dutta n’abandi, 1998; Hedlund n’abandi, 1999). Omuri ebyo, omuhanda gw’okusheenya 1-metili na 2-metili ogwa Pseudomonas sp. CSV86 ekyebeirwe gye aha rurengo rw’eby’amagara n’eby’obuhangwa (Mahajan et al., 1994). 1-Methylnaphthalene neehindurwa omu miringo ebiri. Eky’okubanza, empeta y’omugaju neehindurwa amaizi (empeta etarikuhindurwa eya methylnaphthalene) kubaasa kuhanga cis-1,2-dihydroxy-1,2-dihydro-8-methylnaphthalene, erikweyongyera kuhindurwa oksijeni ekahinduka methyl salicylate na methylcatechol, reero etaaha omu muhanda gw’empeta y’omugati ya carbonavage3). Omuhanda ogu nigwetwa “omuhanda gw’entandikwa ya kaboni”. Omu “muhanda gw’okukyendeeza obutwa” ogwa kabiri, ekibiina kya methyl nikibaasa kuhindurwa amaizi g’omubiri (hydroxymethylnaphthalene) kubaasa kuhanga 1-hydroxymethylnaphthalene, erikwongyera kuhindurwa amaizi g’omubiri kuba 1-naphthoic acid kandi kishohora omu nkora y’okuhinga nk’ekintu ekifiire. Okucondooza kworekire ngu oruganda rwa CSV86 tirurikubaasa kukura aha 1- na 2-naphthoic acid nk’entandikwa ya kaboni n’amaani yonka, ekirikuhamya omuhanda gwarwo gw’okukyendeeza obutwa (Mahajan na bagyenzi be, 1994; Basu na bagyenzi be, 2003). Omuri 2-methylnaphthalene, ekibiina kya methylnaphthalene nikihinguraho okuhinduka kw’amaizi g’omubiri ahabw’okuhinduka kw’amaizi g’omubiri kubaasa kuhanga 2-methylnaphthalene. Okwongyera ahari ekyo, empeta etarikuhindurwa ey’empeta ya naphthalene neehingura omu kuhinduka kw’empeta kubaasa kuhanga dihydrodiol, erikuhinduka 4-hydroxymethylcatechol omu nkora y’okuteerana erikureetaho enzyme kandi etaaha omu muhanda gwa carbon ogwagati kurabira omu muhanda gw’okucwanyagura meta-ring. Omu muringo nigwo gumwe, S. paucimobilis 2322 ekagambwaho ngu neekozesa NDO kuhindura 2-methylnaphthalene, erikwongyera kuhindurwa okwotsya kubaasa kureetaho ebiriisa by’omubiri n’ebiriisa by’omubiri (Dutta et al., 1998).
Naphthoic acids (ezihinduziibwe/ezitarikuhindurwa) n‘ebintu ebirikuruga omu kusheeshasheesha/okuhindura eby‘amagara ebirikubaho omu bwire bw‘okusheenya methylnaphthalene, phenanthrene na anthracene kandi bikarekurwa omu nkora y‘okuhinga erikukoresibwa. Kigambirwe ngu ekimera ky’omu itaka ekirikwetwa Stenotrophomonas maltophilia CSV89 nikibaasa kuhindura 1-naphthoic acid nk’entandikwa ya kaboni (Phale et al., 1995). Okuhindura eby’okurya omu mubiri nikutandika n’okuhindura amaizi g’omubiri omu mpeta y’omugaju kubaasa kuhanga 1,2-dihydroxy-8-carboxynafthalene. Diol erikurugamu neehindurwa katekoli kurabira omu 2-haidrokisi-3-karboksibenzilidenepiruvate, 3-formilsalisiliki asidi, 2-haidroksiisophtalik asidi na salisiliki asidi kandi neetaaha omu muhanda gwa kaboni ogwa rwagati kurabira omu muhanda gw’okusharaho meta-ring (ekishushani 3).
Carbaryl n’omubazi gw’okurwanisa obukooko oburikureeta endwara. Kuruga omu nkora ya Green Revolution omuri India omu myaka ya 1970, okukozesa ebigimusa by’emibazi n’emibazi y’okurwanisa obukooko kireetsireho okweyongyera kw’ebintu ebirikuruga omu by’obuhingi n’oburiisa ebitari by’enshonga (Pingali, 2012; Duttagupta et al., 2020). Ebicweka 55% (hekita 85,722,000) by’eitaka ryona eririmwa omuri Buhindi nirijanjabwa n’emibazi y’okurwanisa obukooko. Omu myaka etaano ehweire (2015–2020), ekicweka ky’eby’obuhingi omuri Buhindi kikoreise omubaro gwa tani 55,000 kuhika 60,000 z’emibazi y’okurwanisa obukooko buri mwaka (Ekitongore ky’eby’obwegyendesereza n’obugwagye bw’abahingi, Minisiture y’eby’obuhingi, Gavumenti ya Buhindi, Okwamunaana 2020). Omu bukiizi-bwa-bumosho n’omugati y’ebibungo bya Gangetic (amahanga againe abantu baingi n’abantu baingi), okukoresa emibazi y’okurwanisa obukooko aha birimwa nikujanjaara munonga, kandi emibazi y’okurwanisa obukooko niyo erikukirayo. Carbaryl (1-naphthyl-N-methylcarbamate) n’omubazi gw’okurwanisa obukooko oburikukoresibwa omu by’obuhingi n’oburiisa bw’Abahinda kandi ogurimu obutwa bwingi kandi oburikukoresibwa omu by’obuhingi bwa Buhindi aha rurengo rwa tani 100–110. Nikikira kuguzibwa omu iziina ry’obushuubuzi erya Sevin kandi nikikoresibwa omu kukyebera ebikooko (ebizimba by’omuriro, ebizimba by’omuriro, ebizimba by’omuriro, ebizimba by’omuriro n’ebindi bingi eby’aheeru) ebirikuteganisa ebirimwa bitari bimwe na bimwe (ebihimba, soya, pamba, ebijuma n’emboga). Obukoko obukye obumwe nka obukooko oburikureeta endwara (NCIB 12042, 12043, C4, C5, C6, C7, obukooko oburikureeta endwara XWY-1), obukooko oburikwetwa Rhodococcus (NCIB 12038), obukooko oburikwetwa Sphingobacterium spp. (CF06), Burkholderia (C3), Micrococcus na Arthrobacter nabyo nibibaasa kukoresibwa omu kukyebera obukooko obundi. Kigambirwe ngu RC100 neebaasa kusheenya ebiriisa bya carbaryl (Larkin na Day, 1986; Chapalamadugu na Chaudhry, 1991; Hayatsu na bagyenzi be, 1999; Swetha na Phale, 2005; Trivedi na bagyenzi be, 2017). Omuhanda gw’okusheenyagurika kwa carbaryl gukyebeirwe munonga aha rurengo rw’eby’amagara, enzymatic n’eby’obuzaarwa omu itaka ery’omutaano erya Pseudomonas sp. Ebika bya C4, C5 na C6 (Swetha na Phale, 2005; Trivedi n’abandi, 2016) (Ekishushani 3). Omuhanda gw’okuhindura eby’okurya nigutandika n’okuhindura amaizi g’omukago gwa ester ahabw’okukoresa carbaryl hydrolase (CH) kubaasa kuhanga 1-naphthol, methylamine na carbon dioxide. 1-naphthol bwanyima neehindurwa 1,2-dihaidrokisinaphtalini ahabwa 1-naphthol haidroksilaasi (1-NH), erikweyongyera kuhindurwa kurabira omu muhanda gwa kaboni ogwa rwagati kurabira omu salisilaiti na gentisate. Ebimwe aha bikooko ebirikushiisha ebiriisa bya carbaryl bikagambwaho ngu nibihindura ebiriisa bya salicylic acid kurabira omu kusharaho empeta ya katekoli (Larkin na Day, 1986; Chapalamadugu na Chaudhry, 1991). Ekikuru, obukooko oburikushiisha naphthalene nibukira kuhindura salicylic acid kurabira omu catechol, obwo obukooko oburikushiisha carbaryl nibukunda kuhindura salicylic acid kurabira omu muhanda gwa gentisate.
Naphthalenesulfonic acid/disulfonic acid n‘ebirikuruga omu naphthylaminesulfonic acid nibibaasa kukoresibwa nk‘ebintu by‘omugati omu kuhanga erangi za azo, ebirikufuka, ebirikujanjaaza, n‘ebindi. 1994). Abajwekyerwa b’ekika kya Pseudomonas (ebika A3, C22) bagambirweho ngu nibatandikaho okuhindura eby’okurya omu mubiri barikuhindura amaizi ga kabiri omu mpeta y’omugaju erimu ekibiina kya sulfonic acid kubaasa kuhanga dihydrodiol, erikweyongyera kuhindurwa 1,2-dihydroxynaphthalene ahabw’okuhindura ekibiina kya sulfiteavage,B1). Ekirugiremu 1,2-dihydroxynaphthalene nikihindurwa omu muhanda gw‘okukyebera ogwa ira, nikwo kugira ngu, omuhanda gwa katekoli nari ogw‘okukyebera (ekishushani 4). Kikashobororwa ngu asidi y‘omubiri n‘ebiriisa by‘omubiri nibibaasa kusheenyagurika kimwe ahabw‘okuteerana kw‘obukooko oburimu emihanda y‘okuhindura ebiriisa (Nortemann et al., 1986). Kikashobororwa ngu memba omwe omu kibiina nikiihaho ekirungo kya aminophthalenesulfonic acid nari hydroxynaphthalenesulfonic acid kurabira omu 1,2-dioxygenation, obwo aminosalicylate nari hydroxysalicylate erikurekurwa omu nkora y’okuhinga nk’ekirungo ekindi ekirikuhindura ebiriisa kandi bwanyima neetwarwa ahaiguru y’ekirungo ekindi ekirikuhindura ebiriisa. Naphthalenedisulfonic acid neeshushana n’ey’omubiri kwonka terikubaasa kusheenyuka gye n’ahabw’ekyo neebaasa kuhindurwa kurabira omu miringo etari emwe n’emwe. Okusheeshasheesha kw’okubanza nikubaho omu bwire bw’okushohoza ebiriisa by’omubiri (regioselective dihydroxylation) eby’empeta y’omubazi n’ekibiina kya sulfonic acid; okusheeshasheesha kwa kabiri nikubaho omu bwire bw’okuhindura asidi ya 5-sulfosalicylic acid n’ekiriisa kya salicylic acid 5-hydroxylase kuhanga asidi ya gentisic, erikutaaha omu muhanda gwa kaboni ogwa rwagati (Brilon et al., 1981) (Ekishushani 4). Enzymes ezirikukora aha kusheenyagura amaizi g’omubiri nazo nizikora aha kuhindura amaizi g’omubiri (Brilon na bagyenzi be, 1981; Keck na bagyenzi be, 2006).
Ekishushani 4. Emihanda y‘okuhindura eby‘okurya omu mubiri ahabw‘okusheenyagura kwa naphthalene sulfonate. Emibaro eri omunda y‘enzindo neejwekyera enzigye ezirikukora aha kuhindura eby‘okurya bya naphthyl sulfonate, ezirikushushana/ezirikushushana n‘enzigye ezishobooroirwe omu kishushani. 3.
PAHs z‘oburemeezi bukye (LMW-PAHs) nizikyendeera, nizikunda amaizi kandi nizibaasa kusheesheka kubi, n‘ahabw‘ekyo tizirikubaasa kusheenyagurika/okusheesheka kw‘obuhangwa. Kwonka obukooko obukye oburikwetwa aerobic nibubaasa kugihindura oxygen obwo burikunywa oxygen (O2) eri omu molekyu. Enzymes ezi nizikira kuba ziri omu kicweka kya oxidoreductases kandi nizibaasa kukora ebikorwa bitari bimwe na bimwe nk’okuhindura empeta y’omugaju (mono- nari dihydroxylation), okukyendeeza amaizi n’okusharaho empeta y’omugaju. Ebintu ebirikuruga omu nkora ezi biri omu mbeera y‘okuhindura ebiri omu mubiri (oxidation) y‘ahaiguru kandi nibibaasa kuhindurwa omu muringo gworobi kurabira omu muhanda gwa kaboni ogwagati (Phale et al., 2020). Enzymes eziri omu muhanda gw’okusheenya zigambirweho kuba nizibaasa kuhindurwa. Omurimo gw’enzigye ezi niguba guri mukye munonga nari gutarikwetegyerezibwa obutafaari bwaba nibukura aha nshonga za kaboni ezoorobi nka shukaari nari asidi z’ebihangwa. Ekipande kya kashatu nikifunza enzymes zitari zimwe na zimwe (ezirikureeta oxygen, hydrolase, dehydrogenases, oxidases, n’ebindi) ezirikwejumba omu kuhindura ebiriisa bya naphthalene n’ebirikurugamu.
Ekipande 3. Emitwarize y’eby’amagara ey’enzigye ezirikukora aha kusheenya naphthalene n’ebirikurugamu.
Okucondooza kwa radioisotope (18O2) kworekire ngu okutaho molekyu za O2 omu mpeta z’omubazi gw’okunuura ahabw’okukoresa oxygenases n’eidaara eririkukirayo obukuru omu kureetaho okusheenyagura kw’ebintu ebiine amagara (Hayaishi na bagyenzi be, 1955; Mason na bagyenzi be, 1955). Okutaho atomu emwe y’omwika (O) kuruga omu molekyu za oxygen (O2) omu nkora y’ahansi nikutandikirwaho ebiriisa by’omunda nari eby’aheeru (ebirikwetwa hydroxylases). Atom endiijo eya oxygen neekyendeera ekahinduka amaizi. Ebirungo by‘omubiri ebirikuruga aheeru nibikyendeeza flavin na NADH nari NADPH, obwo omu birungo by‘omunda flavin neekyendeera ahabw‘ekicweka ky‘ahansi. Emyanya ya hydroxylation neerugamu okutaana omu kuhanga ebintu. Nk’eky’okureeberaho, salisili 1-haidrokisilasi neehindura salisili asidi omu mwanya gwa C1, ekakora katekoli. Aha rubaju orundi, ebiriisa bingi ebirimu ebiriisa 5-hydroxylase (ebirimu ebicweka by‘omubiri ebirikukyendeeza aha nkora y‘okukyendeeza, ebiriisa by‘omubiri, n‘ebiriisa by‘omubiri) nibihindura ebiriisa by‘omubiri omu mwanya gwa C5, bikakora asidi ya gentisic (Yamamoto et al., 1965).
Dioxygenases nizitaho atomu ibiri eza O2 omu itaka. Okurugirira aha bintu ebihangirwe, nibibaganisibwamu ebicweka bibiri ebirikureeta amaizi g’omubiri omu mpeta n’ebicweka ebirikusharaho empeta. Empeta ezirikuhindura amaizi g’omubiri nizihindura ebicweka by’omubiri ebiine omugaju kuba cis-dihydrodiols (nk’eky’okureeberaho, naphthalene) kandi nizijanjaara munonga omu bacteria. Okuhitsya hati, kyorekwa ngu ebiine amagara ebiine ebiriisa ebirikukora nk’empeta nibibaasa kukura aha nshonga zitari zimwe na zimwe ezirimu ebiriisa by’omubiri, kandi ebiriisa ebi nibibaganisibwamu nka NDO (naphthalene), toluene dioxygenase (TDO, toluene), na biphenyl dioxygenase (BPDO, biphenyl). NDO na BPDO zombi nizibaasa kureetaho okuhindura ebiriisa bibiri n’okuhindura ebiriisa by’omubiri ebiri aha rubaju rw’ebintu ebitari bimwe na bimwe ebiine omubazi gw’okushemeza (toluene, nitrotoluene, xylene, ethylbenzene, naphthalene, biphenyl, fluorene, indole, methylnaphthalene, naphthanethraneth, n‘ebindi) (Boyd na Sheldrake, 1998; Phale n‘abandi, 2020). NDO n‘enkora y‘ebicweka bingi erimu ekicweka ky‘omubiri ekirikureetaho okusheeshasheesha, ekirungo ky‘okusheeshasheesha, n‘ekicweka ky‘okusheeshasheesha ekirimu omwanya ogurikukora (Gibson na Subramanian, 1984; Resnick na bagyenzi be, 1996). Ekicweka ky‘okureetaho okuhinduka kwa NDO kirimu ekicweka kihango kya α n‘ekicweka kikye kya β ekitebeekanisiibwe omu nkora ya α3β3. NDO neeruga omu ka mpango y‘ebirungo by‘omwika kandi α-subunit yaayo erimu omwanya gwa Rieske [2Fe-2S] n‘ekyoma ekitari kya heme eky‘omubiri gumwe, ekirikumanyisa obumanyiso bw‘ekicweka ky‘omubiri ekya NDO (Parales et al., 1998). Omu muringo gw’omutaano, omu nkora emwe ey’okureetaho, obutafaari bubiri kuruga omu kukyendeeza kwa pyridine nucleotide nibutwarwa omu ion ya Fe(II) omu mwanya ogurikukora kurabira omu kukyendeeza, ferredoxin n’omwanya gwa Rieske. Ebirikukyendeeza ebirikugyeragyeranisibwa nibikoraho oxygen y‘ebicweka by‘omubiri, ekirikwetengwa omu kuhindura amaizi g‘omu itaka (Ferraro et al., 2005). Obwahati, NDO nkye zonka nizo zishemeziibwe kandi zimanyirwe omu bwijwire kuruga omu miringo etari emwe n’emwe kandi okutegyeka kw’obuzaarwa bw’emihanda erikwejumba omu kusheenya naphthalene kukyebeirwe omu bwijwire (Resnick na bagyenzi be, 1996; Parales na bagyenzi be, 1998; Karlsson na bagyenzi be, 2003). Dioxygenases ezirikusharaho empeta (enzigye ezirikusharaho endo nari ortho-empeta n’enzigye ezirikusharaho exodiol nari meta-empeta) nizikora aha birungo by’omubazi ebirimu amaizi. Nk’eky’okureeberaho, ekirungo ky’omubiri ekirikusharaho empeta y’omubiri (ortho-ring) ni katekoli-1,2-dioxygenase, kandi ekirungo ky’omubiri ekirikusharaho meta-ring nikiba kiri katekoli-2,3-dioxygenase (Kojima na bagyenzi be, 1961; Nozaki na bagyenzi be, 1968). Oyihireho ebiriisa by’omubiri ebitari bimwe na bimwe, hariho n’ebiriisa by’omubiri ebitari bimwe na bimwe ebirikukora aha kusheeshasheesha kw’amaizi g’omubiri ebirimu amajuta g’omubiri, amaarwa g’omubiri n’okukoresa NAD+/NADP+ nk’ebirikwikirizibwa kw’eby’okurya, ebiri bimwe aha bihingwa ebikuru ebirikwejumba omu kuhindura eby’okurya (Gibson na Subramanian, Shahleray, et91;1); ebindi, 2020).
Enzymes nka hydrolases (esterases, amidases) n’ekicweka kya kabiri ekikuru eky’enzigye ezirikukoresa amaizi kusharaho enkoragana z’amaizi kandi zirikworeka obumanyiso bw’ebicweka by’omubiri ebihango. Carbaryl hydrolase n‘ebindi bihingwa ebirikukora nk‘amaizi nibitwarwa nk‘ebicweka by‘omubiri ebirikukora aha nkora y‘omubiri (ebirikukora aha nkora y‘omubiri) omu banywani ba bacteria abatari ba Gram (Kamini et al., 2018). Carbaryl eine akakwate ka amide na ester; n’ahabw’ekyo, neebaasa kuhindurwa amaizi ahabw’okukoresa esterase nari amidase kubaasa kukora 1-naphthol. Carbaryl omu kika kya Rhizobium rhizobium AC10023 na Arthrobacter RC100 zigambirweho ngu nizikora nk’ekirungo kya esterase na amidase, nk’oku biri. Carbaryl omu kika kya Arthrobacter RC100 nayo neekora nk’ekiriisa kya amidase. RC100 eyorekire ngu neebaasa kuhindura amaizi g’emibazi ena ey’omuringo gwa N-methylcarbamate nk’ekiriisa kya kabariri, methomili, asidi ya mefenamik na XMC (Hayaatsu n’abandi, 2001). Kikagambwa ngu CH omu bikooko ebirikwetwa Pseudomonas sp. C5pp neebaasa kukora aha carbaryl (100% y‘emirimo) na 1-nafthyl asetate (36% y‘emirimo), kwonka etari aha 1-naphthyl asetamide, ekirikworeka ngu n‘esterase (Trivedi et al., 2016).
Okucondooza aha by’obuhangwa, enkora y’okutegyeka enzyme, n’okushwijuma eby’obuzaarwa byorekire ngu ebiriisa by’okusheenya caphthalene birimu ebicweka bibiri ebirikutegyeka ebitarikubaasa kuhindurwa nari “operons”: nah (“omuhanda gw’okuza ahaiguru”, okuhindura naphthalene kuba salicylic acid) na sal (“omuhanda gw’ahansi gwa naphthali kuba omuhanda gwa salicylic acid) na sal (“omuhanda gw’ahansi gwa sacholi acidcy kurabira omu sali). Salisiliki asidi n‘ebindi ebirikushushana nayo nibibaasa kukora nk‘ebirikureetaho (Shamsuzzaman na Barnsley, 1974). Omu kubaho kwa shukaari nari asidi z’ebihangirwe, operon neezibirwa. Ekishushani 5 nikyoreka entebekanisa y‘obuzaarwa ehikire ey‘okusheenya naphthalene (omu muringo gwa operon). Ebintu bingi ebiine amaziina/emiringo y’omubazi gwa nah (ndo/pah/dox) bishobooroirwe kandi byashangwa biine okushushana kw’okukuratana kw’ahaiguru (90%) omu miringo yoona eya Pseudomonas (Abbasian et al., 2016). Enyuguta z‘omuhanda gw‘okuza ahaiguru gwa naphthalene okutwarira hamwe zikaba zitebeekanisiibwe omu mubaro gw‘okuhikirizana nk‘oku kirikworekwa omu kishushani 5A. Ekindi kika ky’obuzaarwa, nahQ, nakyo kikagambwa kuba nikikwata aha kuhindura ebiriisa bya naphthalene kandi kikaba nikikira kuba kiri ahagati ya nahC na nahE, kwonka omurimo gwakyo gwenyini gukaguma nigushoboororwa gye. Omu muringo nigwo gumwe, akazaano ka nahY, akarikujunanizibwa aha kusheeshasheesha okurikukwata aha naphthalene, kakashangwa aha muheru gwa nah operon oguri hare omu bicweka ebimwe. Omuri Ralstonia sp., akazaano ka U2 akarikuhandiika ebiriisa bya glutathione S-transferase (gsh) kakashangwa kari ahagati ya nahAa na nahAb kwonka tikaine kakwate n’emitwarize y’okukoresa naphthalene (Zylstra et al., 1997).
Ekishushani 5. Entebekanisa y’obuzaarwa n’obutashushana obureebirwe omu bwire bw’okusheenya naphthalene omu miringo ya bacteria; (A) Omuhanda gw’ahaiguru gw’okusheeshasheesha, okuhindura kw’okusheeshasheesha kuza omu salicylic acid; (B) Omuhanda gwa naphthalene ogwa ahansi, salicylic acid kurabira omu katekoli kuza omu muhanda gwa kaboni ogwa rwagati; (C) salisilik asidi kurabira omu gentisate kuza omu muhanda gwa kaboni ogwa rwagati.
“Omuhanda gw‘ahansi” (sal operon) omu muringo gw‘omutaano niguba gurimu nahGTHINLMOKJ kandi niguhindura salicylate kuba pyruvate na asetaldehyde kurabira omu muhanda gw‘okusharaho katekoli. Omubaro gwa nahG (ogurikuhandiika salicylate hydroxylase) gukashangwa gubiikwa aha muheru gw‘ekicweka ky‘omubiri ekirikuhererukayo (Fig. 5B). Wagyeragyeranisa n’ebindi bika ebirikushiisha naphthalene, omu P. putida CSV86 nah na sal operons nizikoragana kandi nizikwatagana munonga (nk’ebicweka 7.5 kb). Omu bakitiriya abamwe abatari ba Gram, nka Ralstonia sp. U2, Polaromonas ebirikurya ebihimba CJ2, na P. putida AK5, ebihimba nibihindurwa nk’ekirungo kya kaboni eky’ahagati kurabira omu muhanda gwa gentisate (omu muringo gwa sgp/nag operon). Kaseti y‘obuzaarwa neekira kujwekyerwa omu muringo gwa nagAaGHAbAcAdBFCQEDJI, ahu nagR (erikuhandiika omutegyeki w‘omuringo gwa LysR) erikushangwa aha muheru gw‘ahaiguru (ekishushani 5C).
Carbaryl neetaaha omu nkora ya kaboni eya rwagati kurabira omu kuhindura kw’ebiriisa 1-naphthol, 1,2-dihidrokisinaftalini, asidi ya salisiliki, na asidi ya gentisiki (ekishushani 3). Okurugirira aha kucondooza aha by‘obuzaarwa n‘eby‘okurya, kikateebwaho kugabanisa omuhanda ogu omu “ahaiguru” (okuhindura carbaryl kuba salicylic acid), “ahagati” (okuhindura salicylic acid kuba gentisic acid), na “ahansi” (okuhindura gentisic acid kuba ebiri ahagati y‘omuhanda gwa carbon ogwagati) (Singh et al., 201). Okushwijuma kw’eby’obuhangwa okwa C5pp (supercontig A, 76.3 kb) kukashohoza ngu akazaano ka mcbACBDEF nikakwatanisa omu kuhindura carbaryl kuba asidi ya salisiliki, kukuratirwa mcbIJKL omu kuhindura asidi ya salisiliki kuba asidi ya gentisiki, kandi mcbOJKL omu kuhindura asidi ya salisiliki kuba asidi ya gentisiki, kandi mcbOJKP ya asidi y’omugati kuba asidi y’omugati ( ebiriisa by‘omubiri, Trivedi n‘abandi, 2016) (ekishushani 6).
Kigambirwe ngu enzymes ezirikwejumba omu kusheenya ebiriisa by‘omubazi (obariiremu naphthalene na salicylic acid) nizibaasa kureetaho ebirungo ebirikuhikaana kandi zizibirwe enshonga z‘omubazi z‘omubiri ezirikwanguha nka shukaari nari asidi z‘omubiri (Shingler, 2003; Phale et al., 2029). Omu miringo etari emwe n’emwe ey’okuhindura eby’okurya omu mubiri gwa naphthalene n’ebirikurugamu, ebirikutegyeka naphthalene na carbaryl bikyebeirwe kuhika aha rurengo rumwe. Aha naphthalene, ebiriisa ebiri omu mihanda ebiri ey‘ahaiguru n‘ey‘ahansi nibitegyekwa NahR, omutegyeki murungi orikukora nk‘omuringo gwa LysR. Nikyetengyesa ahabw‘okutandikaho omubazi gwa nah ahabw‘okukoresa salicylic acid n‘okukuratiraho okureebeka kwagwo okw‘omutindo gw‘ahaiguru (Yen na Gunsalus, 1982). Ekindi, okucondooza kworekire ngu enkora y‘okutaayaayisa (IHF) na XylR (omutegyeki w‘okuhandiika orikwegamira ahari sigma 54) nabyo nibikuru omu kuhandiika kw‘ebicweka by‘omubiri omu kuhindura eby‘okurya bya naphthalene (Ramos et al., 1997). Okucondooza kworekire ngu enzymes z‘omuhanda gw‘okukingura katekoli meta-ring, nikwo kugira ngu katekoli 2,3-dioxygenase, nizireetaho okubaho kw‘ekiriisa kya naphthalene na/nari salicylic acid (Basu et al., 2006). Okucondooza kworekire ngu enzymes z‘omuhanda gw‘okukingura katekoli ortho-ring, nikwo kugira ngu katekoli 1,2-dioxygenase, nizireetaho okubaho kw‘ekiriisa kya benzoic acid na cis,cis-muconate (Parsek na bagyenzi be, 1994; Tover na bagyenzi be, 2001).
Omu muringo gwa C5pp, ebiriisa bitaano, mcbG, mcbH, mcbN, mcbR na mcbS, nibikora enkodi z’ebirikutegyeka ebiri omu ka ya LysR/TetR ey’ebirikutegyeka eby’okuhandiika ebiine obujunaanizibwa bw’okutegyeka okusheenyagurika kwa carbaryl. Ekicweka ky’omubiri ekirikushushana mcbG kikashangwa kiri haihi munonga n’omubazi gw’okutegyeka ebiri omu muringo gwa LysR PhnS (58% y’okumanyisa amino acid) ogurikwejumba omu kuhindura kw’ebiriisa omu Burkholderia RP00725 (Trivedi et al., 2016). Omubazi gwa mcbH gukashangwa ngu nigwejumba omu muhanda gw’ahagati (okuhindura asidi ya salicylic asidi kuba gentisic acid) kandi n’ogw’omuringo gwa LysR ogurikutegyeka okuhandiika NagR/DntR/NahR omu Pseudomonas na Burkholderia. Abanyabuzaare b’omu ka egi bakagambirwa ngu nibamanya salicylic acid nk’ekintu ekirikureetaho okusheenyagura kw’ebicweka by’omubiri. Aha rubaju orundi, ebiriisa bishatu, mcbN, mcbR na mcbS, ebiri omu miringo ya LysR na TetR ebirikutegyeka okuhandiika, bikamanyirwa omu muhanda gw’okugaruka ahansi (ebiriisa by’omubiri ebiri omu muhanda gwa gentisate-central carbon).
Omuri prokaryotes, emiringo y‘okuhingisa ebiri omu nkora y‘obuzaarwa (okutunga, okuhindura, nari okuhingisa) kurabira omu plasmids, transposons, prophages, ebizinga by‘obuzaarwa, n‘ebintu ebirikuteerana (ICE) nizo nshonga nkuru ezirikureetaho obuveera omu nkora ya bacteria, ekirikureetaho okutunga nari okufeerwa emirimo/emitwarize emwe. Nikibaasisa obukooko kumanyiira embeera z’eby’obuhangwa zitari zimwe na zimwe, ekirikuha oburungi bw’okuhindura eby’okurya aha mugyenyi, nk’okusheenyagura ebirungo by’omugaju. Empindahinduka omu by‘okurya nizikira kubaho kurabira omu kuhindura gye ebikwato by‘okusheenya, emiringo yaabyo y‘okutegyeka, n‘obumanyiso bw‘enzigye, ekirikuhwera omu kusheenya kw‘ebicweka by‘omubiri ebiine akawoowo bingi (Nojiri et al., 2004; Phale et al., 2019, 2020). Kaseti z‘obuzaarwa z‘okusheenya naphthalene zishangirwe ziri aha bintu bitari bimwe na bimwe ebirikugyendera nk‘ebicweka bya plasmids (ebirikuteerana n‘ebitarikuteerana), transposons, genomes, ICEs, n‘okuteerana kw‘ebika bya bacteria ebitari bimwe na bimwe (ekishushani 5). Omuri Pseudomonas G7, nah na sal operons za plasmid NAH7 nizihandiikwa omu muringo gumwe kandi nizikora kimwe aha bikwatiraine n’okuhindura ebiri omu nkora ebirikwetenga okuhindura Tn4653 kubaasa kugiteeraho (Sota et al., 2006). Omu muringo gwa Pseudomonas NCIB9816-4, oruzaaro rukashangwa aha nkora y’okuteerana pDTG1 nk’ebiriisa bibiri (ebirikwingana 15 kb) ebyabaire bihandiikirwe omu nshonga zitari zimwe na zimwe (Dennis na Zylstra, 2004). Omuri Pseudomonas putida AK5, plasmid etari y’okuteerana pAK5 neekora enkodi y’enzigye erikujunanizibwa n’okusheenyagura naphthalene kurabira omu muhanda gw’okusheeshasheesha (Izmalkova et al., 2013). Omu muringo gwa Pseudomonas PMD-1, operon ya nah neeshangwa aha nkora y’obutafaari bw’omubiri, kandi operon ya sal eri aha nkora y’okuteerana pMWD-1 (Zuniga et al., 1981). Kwonka omu Pseudomonas stutzeri AN10, obutafaari bwona oburikusheenya naphthalene (nah na sal operons) nibushangwa aha nkora y‘obutafaari bw‘omubiri kandi nibuteekateekwaho kuba nibuhandiikwa kurabira omu kuhindura, okugaruka kugaita, n‘ebintu ebirikubaho (Bosch et al., 2000). Omu bikooko ebitari by’amazima sp. CSV86, ebikwato bya nah na sal nibishangwa omu nkora ya ICE (ICECSV86). Omubumbi nigurindwa tRNAGly kukuratirwaho okugarukamu okuhikire okurikworeka emyanya y‘okugaruka kuteerana/okutaho (attR na attL) n‘ekicweka ky‘omubiri ekirikushushana n‘ekya phage ekirikushangwa aha nshonda zombi eza tRNAGly, n‘ahabw‘ekyo omubumbi nikishushana n‘ekintu kya ICEclc (ICEclcB13 omu Pseudomonas chlomusica knack). Kigambirwe ngu ebiriisa ebiri aha ICE nibibaasa kuhindurwa ahabw‘okuteerana n‘omubaro gw‘okuhingisa oguri ahansi munonga (10-8), obwo nibihingisa emitwarize y‘okusheenyagura aha muntu orikubitunga (Basu na Phale, 2008; Phale et al., 2019).
Ebicweka by’omubiri ebingi ebirikukora aha kusheenya carbaryl nibishangwa aha plasmids. Obukooko oburikureeta endwara sp. RC100 erimu plasmidi ishatu (pRC1, pRC2 na pRC300) aharizo plasmidi ibiri ezirikuteerana, pRC1 na pRC2, nizihandiika enzymes ezirikuhindura carbaryl kuba gentisate. Aha rubaju orundi, enzigye ezirikwejumba omu kuhindura gentisate kuba ebiriisa bya kaboni eby’omugati nizishangwa aha nkora y’obutafaari bw’omubiri (Hayaatsu et al., 1999). Obukooko oburikuruga omu kika kya Rhizobium. Omuringo gwa AC100, ogurikukoresibwa omu kuhindura carbaryl kuba 1-naphthol, gurimu plasmid pAC200, erikutwara omubazi gwa cehA ogurikuhandiika CH nk’ekicweka kya Tnceh transposon eyehinguririziibwe ebirikukuratana nk’ebintu by’okuta omu nkora (istA na istB) (Hashimoto na bagyenzi be, 2020). Omuri Sphingomonas oruganda rwa CF06, oruzaaro orurikusheenyagura carbaryl niruteekateekwaho kuba ruri omu bihingwa bitaano: pCF01, pCF02, pCF03, pCF04, na pCF05. Okushushana kwa DNA kwa plasmids ezi kuri ahaiguru, ekirikworeka okubaho kw’ekintu ekirikugarukagaruka omu nkora y’obuzaarwa (Feng et al., 1997). Omu nkora y’okusheenya ebiriisa ebirimu ebika bibiri bya Pseudomonas, oruganda rwa 50581 rurimu plasmid erikuteerana pCD1 (50 kb) erikuhandiika ebiriisa bya mcd carbaryl hydrolase gene, obwo ebiriisa ebirikukoragana ebiri omu ruganda rwa 50552 ebirikukora enkora ya 1 Omu mwaka gwa 1991). Omu kika kya Achromobacter WM111, akazaano ka mcd furadan akarikureeta amaizi nikashangwa aha 100 kb plasmid (pPDL11). Ekicweka eki kyorekwa kuba kiriho aha plasmids zitari zimwe na zimwe (100, 105, 115 nari 124 kb) omu bacteria zitari zimwe na zimwe kuruga omu bicweka by’ensi ebitari bimwe na bimwe (Parekh et al., 1995). Omu bikooko ebitari by’amazima sp. C5pp, ebiriisa byona ebirikukora aha kusheenya kwa carbaryl nibishangwa omu nkora y’obuzaarwa erikuhika 76.3 kb y’okukuratana (Trivedi et al., 2016). Okushwijuma ebiri omu nkora y‘obuzaarwa (6.15 Mb) kukashohoza okubaho kwa MGEs 42 na GEIs 36, aharizo MGEs 17 zikaba ziri omu supercontig A (76.3 kb) n‘ebiri omu G+C ebitarikushushana (54–60 mol%), ekirikumanyisa ngu nibibaasa kubaho ebirikubaho omu nkora y‘okuhingisa ebiri omu nkora y‘obuzaarwa (al20T). P. putida XWY-1 neeyoreka entebekanisa nk’egyo ey’ebicweka by’omubiri ebirikushiisha carbaryl, kwonka ebicweka ebi nibishangwa aha plasmid (Zhu et al., 2019).
Oyihireho okukora gye kw‘eby‘okurya aha rurengo rw‘eby‘amagara n‘eby‘obuhangwa, obukooko obukye nabwo nibworeka ebindi bintu nari okugarukamu nk‘okuhindura eby‘okurya aha mutwe gw‘obutafaari, okutaho ebicweka, okukoresa okurikukirayo, okukora eby‘okurya by‘omubiri, n‘ebindi, ebirikubahwera kuhindura gye eby‘okurya ebirimu aromatic envitron pollutents in (Fig7).
Ekishushani 7. Enkora z‘okugarukamu z‘obutafaari zitari zimwe na zimwe ez‘obukooko oburikusheenya amaizi g‘omubiri oburungi ahabw‘okusheenya gye ebirungo by‘okushiisha eby‘aheeru.
Ebigarukwamu bya chemotactic nibitwarwa nk‘enshonga ezirikwongyera aha kusheenyagura kw‘ebintu ebirikushiisha eby‘obuhangwa omu nkora z‘eby‘obuhangwa ezitarikushushana. (2002) bakooreka ngu okujanjaba kw’eby’okurya ebirimu obukooko oburikwetwa Pseudomonas sp. G7 kuhika ahari naphthalene kikongyera aha mubaro gw’okusheenya naphthalene omu nkora z’amaizi. Ekika ky’omukibira G7 kikashiisha naphthalene omu bwangu bwingi kukira ekika ky’omubazi ekirikuhinduka ekitaine chemotaxis. Puroteni ya NahY (amino acids 538 eziine membrane topology) zikashangwa zihandiikirwe hamwe n’ebicweka by’omubiri ebirikukora aha nkora ya metacleavage aha plasmid ya NAH7, kandi nk’ebirikuhindura ebiriisa, puroteni egi neereebeka nk’erikukora nk’ekirungo ky’okusheeshasheesha kwa naphthalene (Grimm na Harwood 1997). Okucondooza okundi okwakozirwe Hansel na bagyenzi be. (2009) bakooreka ngu puroteyini neekora nk’eby’obuhangwa (chemotactic), kwonka omubaro gwayo gw’okusheenyagurika nigukira. (2011) bakooreka okugarukamu kw’eby’obuhangwa kwa Pseudomonas (P. putida) aha nshaho y’omuyaga, ahu okujanjaara kw’omuyaga gw’omuyaga kwarugiremu okutambura kw’eby’okurya okutarimu kuhinduka omu butafaari, ekyabaire nikitegyeka okugarukamu kw’eby’obuhangwa kw’obutafaari. Abacondoozi bakakoresa emitwarize egi ey’okukoresa emibazi (chemotactic) kuhangaho obukooko obukye oburikubaasa kutunguura omubaro gw’okusheenyagura. Okucondooza kworekire ngu emihanda y’okuhurira ebiri omu mubiri (chemosensory pathways) nayo neetebeekanisa emirimo endiijo ey’obutafaari nk’okugabanisa obutafaari, okutebeekanisa enzindo y’obutafaari, n’okukora ebishushani by’ebihangirwe ebiine amagara, obwo nibihwera okutegyeka omubaro gw’okusheenya. Kwonka, okukoresa omugasho ogu (chemotaxis) ahabw‘okusheenya gye nikiremesibwa oburemeezi bwingi. Ebizibu ebikuru ni: (a) ebikwato by‘okutunga paralogous ebitarikushushana nibimanya ebirungo/ebirungo bimwe; (b) okubaho kw’ebindi bihingwa ebirikutunga obuhwezi, nikwo kugira ngu, okuteerana kw’amaani; (c) entaaniso z‘okukuratana z‘amaani omu myanya y‘okuhurira ey‘eka emwe y‘okutunga; na (d) okubura amakuru aha puroteyini z‘okuhurira obukooko obukuru (Ortega na bagyenzi be, 2017; Martin-Mora na bagyenzi be, 2018). Obumwe, okusheenya kw‘ebintu ebiine amagara (biodegradation) kw‘amaizi g‘omubiri aromatic hydrocarbons nikureetaho ebintu bingi ebirikuhindura ebiriisa/ebintu ebiri ahagati, ebirikubaasa kuba eby‘okurya by‘omubiri (chemotactic) aha guruupu emwe ya bacteria kwonka ebirikubinga aha bindi, ekirikwongyera kugumizamu omu nkora. Okubaasa kumanya enkoragana y‘ebicweka by‘omubiri (amaizi g‘omubazi) n‘ebintu ebirikutunga emibazi, tukakora puroteyini z‘okuhurira (PcaY, McfR, na NahY) turikuteerana emyanya y‘okuhurira n‘okumanyisa eya Pseudomonas putida na Escherichia coli, ezirikuta omutima aha bikwatiraine n‘okutunga asidi z‘omugaju, TCA naspectly, alLuuthaly, intermedia. 2019).
Ahansi y’okutegyekwa kwa naphthalene n’ebindi bihingwa ebiine amaizi g’omubazi (PAHs), omubumbi w’ekibunu ky’obukooko n’obuhame bw’obukooko obukye nibihinduka munonga. Okucondooza kworekire ngu naphthalene neeteganisa enkoragana y’orujegyere rwa acyl kurabira omu nkoragana z’amaizi, obwo neeyongyera aha kuzimba n’okusheesheka kw’omubiri (Sikkema et al., 1995). Okurwanisa ekizibu eki eky‘akabi, obukooko nibutebeekanisa okusheeshasheesha kw‘omubiri obwo burikuhindura omubaro n‘ebicweka by‘ebishaju ebiri ahagati y‘ebishaju ebiine amataagi ga iso/anteiso n‘okuhindura ebishaju ebitarikujwanzya cis omu bishaju ebirikuhikaana (Heipieper na de Bont, 1994). Omuri Pseudomonas stutzeri ezakuzire aha mubazi gwa naphthalene, omubaro gw’ebishaju ebiijwire n’ebitarimu gukeeyongyera kuruga ahari 1.1 kuhika ahari 2.1, obwo omu Pseudomonas JS150 omubaro ogu gweyongyeire kuruga ahari 7.5 kuhika ahari 12.0 (Mrozik et al., 2004). Ku byakuzire aha naphthalene, obutafaari bwa Achromobacter KAs 3–5 bukayoreka okuteerana kw’obutafaari okwehinguririize obutafaari bwa naphthalene n’okukyendeera kw’eshagama y’aha mutwe gw’obutafaari (kuruga ahari -22.5 kuhika ahari -2.5 mV) erikuhererukayo n’okuteerana kw’obutafaari bw’omubiri n’okuhinduka kw’obutafaari bwa alhafa, ekirikworeka empindahinduka omu nkora y’obutafaari bwa alhafa. 2019). N‘obu empindahinduka z‘obutafaari/ahaiguru ziraabe nizikwatagana butunu n‘okutwara gye ebirungo by‘omubazi, enkora z‘eby‘amagara eziine akakwate n‘eby‘amagara tizikabonezibwa gye. Okuhindura omu nkora y‘obutafaari tikukoresiibwe munonga kutunguura enkora z‘ebihangirwe (Volke na Nikel, 2018). Okusazibwamu kw’ebicweka by’omubiri ebirikuteganisa okugabanisa obutafaari nikireetaho empindahinduka omu nkora y’obutafaari. Okusazibwamu kw’ebicweka by’omubiri ebirikuteganisa okugabanisa obutafaari nikireetaho empindahinduka omu nkora y’obutafaari. Omuri Bacillus subtilis, puroteyini y‘obutafaari bw‘omubiri SepF eyorekwa ngu neekwata aha kuhanga obutafaari bw‘omubiri kandi neeyetengyesa omu matembezo agarikurataho ag‘okugabanisa obutafaari, kwonka ti n‘obuzaarwa bw‘omugasho. Okusazibwamu kw’ebicweka by’omubiri ebirikukora enkodi y’ebicweka by’omubiri ebiri omu Bacillus subtilis kikarugamu okutunguuka kw’obutafaari, okweyongyera kw’omubaro gw’okukura kw’omutaano, n’okutunguura obushoboorozi bw’okukora enzyme (Cui et al., 2018).
Okucwanyagura omuhanda gw’okusheenya carbaryl kuteekateekirwe kubaasa kutunga okusheenya okuhikire kw’ebika bya Pseudomonas C5pp na C7 (Kamini et al., 2018). Nikiteekateekwaho ngu carbaryl neetwarwa omu mwanya gwa periplasmic kurabira omu septum y‘aheeru y‘ekibunu na/nari kurabira omu porins ezirikujanjaara. CH n’enzigye eri omu nkora ya periplasmic erikuhwera omu kuhindura amaizi ga carbaryl kuhinduka 1-naphthol, erikugumaho munonga, erikukunda amaizi kandi erimu obutwa. CH neeshangwa omu periplasm kandi eine akakwate kakye na carbaryl, n‘ahabw‘ekyo neetegyeka okukora kwa 1-naphthol, obwo neezibira okuteerana kwayo omu butafaari n‘okukyendeeza obutwa bwayo aha butafaari (Kamini et al., 2018). Ekirikurugamu 1-naphthol nikitwarwa omu nkora y‘omubiri (cytoplasm) kurabira omu nkora y‘omunda y‘omubiri kurabira omu kugabanisamu n‘/nari okujanjaara, reero bwanyima kihindurwa amaizi kuba 1,2-dihydroxynaphthalene ahabw‘enzigye y‘omutindo gw‘ahaiguru 1NH ahabw‘okwongera kuhindura eby‘okurya omu muhanda gwa kaboni ogw‘ahagati.
N’obu obukooko obukye buraabe bwine obushoboorozi bw’obuzaarwa n’okuhindura eby’okurya omu kusheenya enshonga za kaboni ezirikwetwa xenobiotic carbon, omutindo gw’okuzikoresa (nikwo kugira ngu, okukunda okukoresa enshonga za kaboni ezoorobi kukira ezigumire) n’ekizibu kihango omu kusheenya enshonga z’ebintu ebiine amagara. Okubaho n‘okukoresa enshonga za kaboni ezoorobi nikukyendeeza aha nkora y‘obutafaari oburikuhandiika enzymes ezirikushiisha enshonga za kaboni ezigumire/ezitarikukunda nka PAHs. Eky‘okureeberaho ekikyebeirwe gye n‘okugira ngu shukaari n‘amaizi g‘omubiri byagambwaho hamwe na Escherichia coli, shukaari neekoresibwa gye kukira amaizi g‘omubiri (Jacob na Monod, 1965). Pseudomonas egambirweho ngu neeshiisha PAHs zitari zimwe na zimwe n’ebintu ebitari bimwe na bimwe nk’entandikwa ya carbon. Omutindo gw’okukozesa entandikwa ya kaboni omu Pseudomonas ni asidi z’ebihangwa > shukaari > ebirungo by’omugaju (Hylemon na Phibbs, 1972; Collier na bagyenzi be, 1996). Kwonka, hariho ekirikutaanisaho. Ekirikushemeza, obukooko oburikwetwa Pseudomonas sp. CSV86 neeyoreka omutindo gw‘omutaano gw‘okukuratana ogurikukirayo kukoresa ebiriisa by‘omugaju (benzoic acid, naphthalene, n‘ebindi) okukira shukaari kandi neehindura ebiriisa by‘omubazi hamwe n‘ebiriisa by‘omubiri (Basu et al., 2006). Omuri obukooko obu, ebiriisa by’okusheenya n’okutwara amaizi g’omubazi tibirikukyendeera n’obu haakubaho enshonga ya kabiri eya kaboni nka shukaari nari asidi z’ebihangirwe. Ku byakuzire omu nkora ya shukaari n’ebiriisa by’omugaju, kikareebeka ngu ebiriisa by’okutwara shukaari n’okuhindura eby’okurya bikakyendeera, ebiriisa by’omubazi bikakoresibwa omu nkora y’okubanza ey’okuhandiika, kandi shukaari ekakoresibwa omu nkora ya kabiri ey’okuhandiika (Basu et al., 2006; Choudhary et al201). Aha rubaju orundi, okubaho kwa asidi z’ebihangirwe tikuine kakwate n’okureebeka kw’okuhindura kw’amaizi g’omubiri (aromatic hydrocarbon metabolism), n’ahabw’ekyo obukooko obu nibuteekateekwaho kuba oruganda orurikwenda kucondooza aha kusheenyagura kw’ebintu ebiine amagara (Phale et al., 2020).
Nikimanyirwa gye ngu okuhinduka kw‘ebihangirwe ebiri omu hydrocarbon nikubaasa kureetera okushoberwa kw‘okwotsya n‘okutunguuka kw‘enzigye z‘okurwanisa obukooko obukye. Okusheenyagura kw‘ebintu ebiine amagara (naphthalene) okutarikukora gye omu butafaari bw‘omutindo ogutarikuhinduka n‘omu kubaho kw‘ebintu by‘obutwa nikureetaho okutandika kw‘ebika by‘omwika ogurikukora (ROS) (Kang et al. 2006). Ahabw’okugira ngu enzymes ezirikushiisha naphthalene zirimu ebirundo by’ekyoma-sulfur, ahansi y’okugyemeserezibwa kw’okwotsya, ekyoma ekiri omu heme na puroteyini z’ekyoma-sulfur nibiija kuhindurwa, ekirikureetaho puroteyini obutakora. Ferredoxin-NADP+ reductase (Fpr), hamwe na superoxide dismutase (SOD), nibireetaho okugarukamu kw‘okugaruka enyima ahagati ya NADP+/NADPH n‘ebicweka bibiri bya ferredoxin nari flavodoxin, obwo nibisheenya ROS kandi bikagaruraho omwanya gw‘ekyoma-ekibiriiti ahansi y‘okugyemeserezibwa kw‘okwotsya (Li et06). Kigambirwe ngu Fpr na SodA (SOD) zombi omu Pseudomonas nizibaasa kureetwaho okushoberwa kw‘okwotsya, kandi okweyongyera kw‘emirimo ya SOD na catalase kukareebeka omu miringo ena ya Pseudomonas (O1, W1, As1, na G1) omu bwire bw‘okukura omu mbeera ezirimu naphthalene (K et.0). Okucondooza kworekire ngu okwongyeraho ebiriisa ebirikurwanisa obukooko nk’ebirikwetwa ascorbic acid nari ferrous iron (Fe2+) nikibaasa kwongyera aha kukura kwa naphthalene. Rhodococcus erythropolis ku yaakuzire omu nkora ya naphthalene, okuhandiika kw’ebicweka by’omubiri ebiine akakwate n’okuteganisibwa kw’okwotsya P450 ebirimu sodA (Fe/Mn superoxidase), sodC (Cu/Zn superoxidase), na recA kukaba kweyongyera (Sazykin et al., 201). Okugyeragyeranisa omubaro gw‘obutafaari bwa Pseudomonas oburikuhinga omu naphthalene kukooreka ngu okutunguura puroteyini zitari zimwe na zimwe eziine akakwate n‘okugarukamu kw‘okushoberwa kw‘okwosya n‘omuringo gw‘okugumisiriza okushoberwa (Herbst et al., 2013).
Obukoko obukye bukagambwaho ngu nibureetaho ebirungo by’amagara (biosurfactants) ahansi y’ebikorwa by’enshonga z’amaizi. Ebirungo ebi ebirikukora aha itaka n’ebintu ebirikukora aha itaka ebirikukora aha itaka ebirikubaasa kuhanga ebirungo aha nkoragana y’amajuta n’amaizi nari empeho n’amaizi. Eki nikitunguura okusheeshasheesha kw’ebishuba kandi nikihwera omu kusheeshasheesha kw’amaizi g’omubazi, ekirikureetaho okusheenyagura kw’ebintu ebiine amagara (Rahman et al., 2002). Ahabw’ebintu ebi, ebirungo bya biosurfactants nibikoresibwa munonga omu makorero gatari gamwe na gamwe. Okwongyeraho emibazi y‘okukoresa aha itaka nari ebiriisa by‘amagara aha buhangwa bwa bacteria nikibaasa kwongyera aha buhanguzi n‘omubaro gw‘okusheenyagura kwa hydrocarbon. Omuri ebyo ebirikukora aha itaka, ebiriisa ebirikuruga omu itaka ry’ebishaka ebirikwetwa Pseudomonas aeruginosa bikyebeirwe munonga kandi byashoboororwa (Hisatsuka na bagyenzi be, 1971; Rahman na bagyenzi be, 2002). Okwongyera ahari ekyo, ebindi biika by’ebintu ebirikukora aha itaka harimu ebirungo by’amaizi (ebirungo by’omubiri kuruga omu bihingwa by’omubiri), ebiriisa by’omubiri 378 (ebirikuruga omu bihingwa by’omubiri) (Rosenberg na Ron, 1999), ebiriisa by’omubiri ebirikuruga omu bihingwa by’omubiri (Ba1999), 1999). na Hallberg, 2002), n’ebintu ebirikukora aha itaka kuruga omu bihingwa ebirikwetwa Bacillus (Siegmund na Wagner, 1991) n’ebihingwa ebirikwetwa Bacillus (Zhi na bagyenzi be, 2017). Ebintu ebi eby’amaani ebirikukora aha itaka nibyorekwa ngu nibikyendeeza aha kuhutaara kw’aha itaka kuruga ahari 72 dynes/cm kuhika ahansi ya 30 dynes/cm, ekirikubaasisa okunywa gye kwa hydrocarbon. Kigambirwe ngu obukooko oburikwetwa Pseudomonas, Bacillus, Rhodococcus, Burkholderia n’ebindi bika bya bacteria nibibaasa kureetaho ebihingwa ebitari bimwe na bimwe ebirikwegamira aha nshaho n’ebishaju by’omubiri byakuzibwa omu nkora y’okuriisa ebiriisa by’omubiri (Kanga et al., 1997., Puntus20). Pseudomonas maltophilia CSV89 neebaasa kureetaho ekirungo ky’ebihangirwe ebiri aheeru y’obutafaari bwa Biosur-Pm kyakuzibwa aha birungo by’omubazi nk’ebiriisa by’omubazi (Phale et al., 1995). Enkora y’okukora Biosur-Pm ekooreka ngu okukora kwayo n’omuringo ogurikurugiirira aha kukura n’omu pH. Kikashangwa ngu omubaro gwa Biosur-Pm ogurikuruga omu butafaari aha pH etaine rubaju gukaba guri ahaiguru y’ogwa pH 8.5. Obutafaari obukuzire aha pH 8.5 bukaba buri obw’okukunda amaizi kandi bukaba bwine akakwate kakuru n’ebintu ebirimu aromatic na aliphatic compounds kukira obutafaari obukuzire aha pH 7.0. Omuri Rhodokoki spp. N6, omubaro gw‘ahaiguru gwa kaboni na nitrogen (C:N) n‘okukyendeeza aha kyoma n‘embeera nungi z‘okukora ebirungo by‘omubiri ebiri aheeru y‘obutafaari (Mutalik et al., 2008). Okugyezaho kukozirwe kutunguura okukora kw’ebintu ebiine amagara (surfactins) barikutunguura ebika by’ebintu n’okubiteeka. Kwonka, titer y’ebintu ebirikukora aha itaka omu nkora y’okuhinga eri ahansi (1.0 g/L), ekirikureetaho oburemeezi omu kuhanga ebintu bingi (Jiao na bagyenzi be, 2017; Wu na bagyenzi be, 2019). Nahabwekyo, emiringo y’okuhindura ebiri omu nkora y’obuzaarwa ekozesiibwe kutunguura oku erikukora. Kwonka, okuhindura kwayo omu by’obuhangwa nikuguma ahabw’obuhango bw’operon (∼25 kb) n’okutebeekanisa kw’ebihangirwe ebigumire okw’enkora y’okuhurira ekicweka ky’abantu (Jiao et al., 2017; Wu et al., 2019). Omubaro gw’okuhindura omu nkora y’obuzaarwa gukozirwe omu bacteria ya Bacillus, okukira munonga kugyendereire kwongyera aha kureetaho ebiriisa by’omubiri (surfactin) barikuhindura ekirikureetaho (srfA operon), okushohoza munonga puroteyini y’okushohoza ebiriisa by’omubiri YerP n’ebintu ebirikutegyeka ComX na PhrC (Jiao et al., 201). Kwonka, emiringo egi ey’okuhindura ebiri omu nkora y’obuzaarwa etungire okuhindura omu nkora y’obuzaarwa emwe nari bikye kandi tekahikire aha kugikora omu by’obushuubuzi. Nahabwekyo, okweyongyera kwega aha miringo y‘okutunguura ebirikwegamira aha kumanya nikyetengyesa.
Okucondooza aha kusheenyagura kwa PAH nikukira kukorwa omu mbeera z‘omutindo z‘okukyebera. Kwonka omu myanya erimu obukooko nari omu myanya erimu obukooko, ebintu bingi ebitarikushushana n’ebiine amagara (obutagatsi, pH, oxygen, okutunga ebiriisa, okugira ebiriisa ebiri ahansi y’itaka, ebindi bihangirwe ebitari bimwe na bimwe, okuzibira ebirugire omu kuhendera, n’ebindi) byorekwa ngu nibihindura kandi nibikwata aha bushoborozi bw’ebintu ebikye ebirikusheenya.
Ebirikuba biriho biine akakwate kakuru n’okusheenyagura eby’obuhangwa bya PAH. Ebiriisa byaba nibyeyongyera, okuteerana kw’omwika ogurikushuuma nikukyendeera, ekirikuteganisa okuhindura kw’ebintu ebikye ebiri omu mwanya, ahabw’okuba nibyetenga oxygen y’omu molekyu nk’emwe aha nshonga z’okukoresa oxygenases ezirikukora hydroxylation nari ring cleavage reactions. Nikikira kumanyirwa ngu ebirikuba biri ahaiguru nibihindura PAHs z‘omuzaire kuba ebirungo by‘obutwa bingi, obwo nibizibira okusheenyagura kw‘ebintu ebiine amagara (Muller et al., 1998).
Kimanyirwe ngu emyanya mingi erimu obukooko bwa PAH eine pH y‘ahaiguru munonga, nk‘emyanya erimu obukooko bw‘okusheenya amaizi g‘ebirombe bya asidi (pH 1–4) n‘emyanya y‘okuhindura gaasi y‘obuhangwa/amakara erimu obukooko bw‘amaizi g‘omugyera (pH 8–12). Embeera ezi nizibaasa kukwata munonga aha nkora y‘okusheenya eby‘obuhangwa. Nahabwekyo, otakakozeise obukooko obukye omu kuboneza eby’obuhangwa, nikihaburwa kuhindura pH orikuteekamu emibazi ehikire (eine obushoboorozi bw’okukyendeeza aha kusheeshasheesha kw’omubiri) nk’okukyendeeza aha kusheeshasheesha kw’eitaka nari ammonium nitrate ahabw’eitaka eririmu alkaline nari okutaho liming n’ekiriisa kya calcium si Bolen carbonate nari magne. 1995;
Okuha oxygen omu mwanya ogurikukwatwaho nikyo kirikuzibira omubaro gw‘okusheenyagura kwa PAH. Ahabw’embeera za redox z’eby’obuhangwa, emiringo y’okugaruzaho eby’obuhangwa omu mwanya (in situ bioremediation) neekira kwetenga okutaho oxygen kuruga aheeru (okuhinga, okusheeshasheesha kw’omuyaga, n’okwongyeraho emibazi) (Pardieck et al., 1992). Odenkranz n’abandi. (1996) bakooreka ngu okwongyera magnesium peroxide (ekirungo ekirikurekura oxygen) omu nkungu y’amaizi erimu obukooko nikibaasa kuboneza gye ebirungo bya BTEX. Okucondooza okundi kukacondooza aha kusheenyagura kwa in situ kwa phenol na BTEX omu nkungu y’amaizi erimu obukooko barikutamu sodium nitrate n’okwombeka ebiina by’okushohoza kubaasa kutunga okugaruzaho eby’obuhangwa (Bewley na Webb, 2001).