Researchers have identified and engineered an enzyme which can digest and consume some of our most commonly polluting plastiki providing a hope for recycling and fighting uchafuzi wa mazingira
Kichafua plastiki ni changamoto kubwa ya kimazingira duniani kote katika mfumo wa plastiki uchafuzi wa mazingira and optimal solution to this problem still remains elusive. Most plastiki are made from petroleum or natural gas which are non-renewable resources that are extracted and processed using energy-intensive techniques. Thus, their manufacturing and production itself is very destructive for fragile ecosystems. The destruction of plastic (mostly by incineration) causes air, maji na ardhi uchafuzi wa mazingira. About 79 per cent of plastic produced over the last 70 years has been thrown away, either into landfill sites or into the general environment while only about nine per cent is recycled with the rest incinerated. This process of incineration exposes vulnerable workers to toxic chemicals which include cancer-causing substances. The oceans are said to contain some 51 trillion microplastic particles and are slowly depleting marine life. Some of the plastic microparticles get blown away in air leading to uchafuzi wa mazingira and it’s a real possibility that we might be inhaling them. No one could have predicted in the 1960s that advent and popularity of plastics would one day become a burden with huge plastic waste found floating in our beautiful oceans, air and dumped on our precious lands.
plastiki packaging is the biggest threat and most corrupt use of plastics. But the problem is that plastic bag is everywhere, used for every little purpose and there is no control over its usage. This kind of synthetic plastic does not biodegrade, instead just sits and accumulates in landfills and contributes to environmental uchafuzi wa mazingira. There have been initiatives for “complete plastic ban”, especially polystyrene which is used in packaging. However, this is not leading to desired results as plastic is still ubiquitous in land, air and water and is ever growing. Safe to say that plastic may not even be visible to the naked eye all the time but it’s everywhere! It is unfortunate that we are unable to tackle the plastic material’s recycling and dispose problem.
Katika utafiti uliochapishwa katika Kesi za Chuo cha Kitaifa cha Sayansi USA, watafiti wamegundua asili inayojulikana enzyme ambayo hula kwenye plastiki. Huu ulikuwa ugunduzi wa bahati walipokuwa wakichunguza muundo wa kimeng'enya ambacho kilipatikana kwenye taka tayari kwa kuchakatwa katika kituo kimoja huko Japani. Kimeng'enya hiki kiitwacho Ideonella sakaiensis 201-F6, kinaweza "kula" au "kulisha" plastiki iliyo na hati miliki ya PET au polyethilini terephthalate ambayo hutumiwa sana katika mamilioni ya tani za chupa za plastiki. Kimeng'enya kimsingi kiliruhusu bakteria kuharibu plastiki kama chanzo chao cha chakula. Hakuna suluhu za kuchakata kwa sasa kwa PET na chupa za plastiki zilizotengenezwa kwa PET zinaendelea kwa zaidi ya mamia ya miaka katika mazingira. Utafiti huu ulioongozwa na timu katika Chuo Kikuu cha Portsmouth na Maabara ya Kitaifa ya Nishati Mbadala ya Idara ya Marekani (NREL) umetoa matumaini makubwa.
Kusudi la asili lilikuwa kuamua muundo wa fuwele wa pande tatu wa kimeng'enya hiki asilia (kinachoitwa PETase) na kutumia habari hii kuelewa jinsi kimeng'enya hiki kinavyofanya kazi. Walitumia miale mikali ya X-rays - ambayo inang'aa mara bilioni 10 kuliko jua - ili kufafanua muundo na kuona atomi za kibinafsi. Mihimili hiyo yenye nguvu iliwezesha kuelewa utendakazi wa ndani wa kimeng'enya na kutoa michoro sahihi ili kuweza kutengeneza vimeng'enya kwa haraka na kwa ufanisi zaidi. Ilifunuliwa kwamba PETase inaonekana sawa na kimeng'enya kingine kinachoitwa cutinase isipokuwa PETase ina kipengele maalum na tovuti "iliyo wazi" zaidi, ambayo inadhaniwa kuchukua polima zinazotengenezwa na binadamu (badala ya zile za asili). Tofauti hizi mara moja zilionyesha kwamba PETase inaweza kubadilishwa zaidi hasa katika mazingira yenye PET na hivyo inaweza kuharibu PET. Walibadilisha tovuti inayotumika ya PETase ili kuifanya ionekane zaidi kama cutinase. Kilichofuata ni matokeo ambayo hayakutarajiwa kabisa, kibadilishaji cha PETase kiliweza kuharibu PET bora zaidi kuliko PETase asilia. Kwa hivyo, katika mchakato wa kuelewa na kujaribu kuboresha uwezo wa kimeng'enya asilia, watafiti walimaliza kwa bahati mbaya kutengeneza kimeng'enya kipya ambacho kilikuwa bora zaidi kuliko kimeng'enya asilia katika kuvunja PET. plastiki. Kimeng'enya hiki kinaweza pia kuharibu polyethilini furandicarboxylate, au PEF, kibadala cha kibayolojia cha plastiki za PET. Hii ilileta matumaini ya kukabiliana na substrates nyingine kama PEF (Polyethilini Furanoate) au hata PBS (Polybutylene succinate). Zana za uhandisi wa kimeng'enya na mageuzi zinaweza kutumika mara kwa mara kwa uboreshaji zaidi. Watafiti wanatafuta njia ya kuboresha kimeng'enya ili kazi yake iweze kuingizwa katika usanidi wa nguvu wa viwanda vikubwa. Mchakato wa kihandisi unafanana sana na vimeng'enya ambavyo kwa sasa vinatumika katika sabuni za kuosha kibiolojia au katika utengenezaji wa nishati ya mimea. Teknolojia ipo na kwa hivyo uwezekano wa viwanda unapaswa kupatikana katika miaka ijayo.
Utafiti zaidi unahitajika ili kuelewa baadhi ya vipengele vya utafiti huu. Kwanza, kimeng'enya hugawanya vipande vikubwa vya plastiki katika vipande vidogo, kwa hivyo inasaidia urejelezaji wa chupa za plastiki lakini plastiki hii yote inahitaji kurejeshwa kwanza. Plastiki hii "ndogo" ikipatikana inaweza kutumika kuzirejesha kwenye chupa za plastiki. Kimeng'enya hakiwezi "kwenda na kutafuta plastiki peke yake" katika mazingira. Chaguo moja lililopendekezwa linaweza kuwa kupanda kimeng'enya hiki kwenye baadhi ya bakteria ambayo inaweza kuanza kuvunja plastiki kwa kiwango cha juu zaidi huku ikistahimili halijoto ya juu. Pia, athari ya muda mrefu ya kimeng'enya hiki bado inahitaji kueleweka.
Athari za suluhisho kama hilo la kibunifu la kushughulikia taka za plastiki zingekuwa za juu sana katika kiwango cha kimataifa. Tumekuwa tukijaribu kukabiliana na tatizo la plastiki tangu ujio wa plastiki yenyewe. Kumekuwa na sheria zinazopiga marufuku matumizi ya plastiki moja na pia plastiki iliyorejelewa sasa inapendelewa kila mahali. Hata hatua ndogo kama vile kupiga marufuku mifuko ya plastiki katika maduka makubwa imekuwa kwenye vyombo vya habari. Jambo ni kwamba, tunahitaji kuchukua hatua haraka ikiwa tungependa kuhifadhi yetu sayari from plastic uchafuzi wa mazingira. Though we must carry on adopting recycling in our everyday life while encouraging our children to do so as well. We still need a good long-term solution which can go hand in hand with our own individual efforts. This research marks a beginning for tackling one of the biggest problems which our sayari inakabiliwa.
***
{Unaweza kusoma karatasi asili ya utafiti kwa kubofya kiungo cha DOI kilichotolewa hapa chini katika orodha ya (vyanzo) vilivyotajwa}
Chanzo (s)
Harry P na wenzake. 2018. Tabia na uhandisi wa polyesterase yenye kunukia ya plastiki yenye kunukia. Kesi za Chuo cha Kitaifa cha Sayansi. https://doi.org/10.1073/pnas.1718804115
