Philippine Daily Inquirer - - WORLD -

TAMPA— Re­searchers in the United States and Britain have ac­ci­den­tally en­gi­neered an en­zyme which eats plas­tic and may even­tu­ally help solve the grow­ing prob­lem of plas­tic pol­lu­tion, a study said on Mon­day.

More than 8 mil­lion tons of plas­tic are dumped into the world’s oceans ev­ery year, and con­cern is mount­ing over this petroleum-de­rived prod­uct’s toxic legacy on hu­man health and the en­vi­ron­ment.

Nat­u­ral bac­terium

De­spite re­cy­cling ef­forts, most plas­tic can per­sist for hun­dreds of years in the en­vi­ron­ment, so re­searchers are search­ing for bet­ter ways to elim­i­nate it.

Sci­en­tists at the Uni­ver­sity of Portsmouth and the US En­ergy Depart­ment’s Na­tional Re­new­able En­ergy Lab­o­ra­tory de­cided to fo­cus on a nat­u­rally oc­cur­ring bac­terium dis­cov­ered in Japan a few years ago.

Ja­panese re­searchers be­lieve the bac­terium evolved fairly re­cently in a waste re­cy­cling cen­ter, since plas­tics were not in­vented un­til the 1940s.

Known as Ideonella sakaien­sis, it ap­pears to feed ex­clu­sively on a type of plas­tic known as poly­eth­yl­ene tereph­tha­late (PET), used widely in plas­tic bot­tles.

A use­ful mu­ta­tion

The re­searchers’ goal was to un­der­stand how one of its en­zymes called PETase worked, by fig­ur­ing out its struc­ture.

“But they ended up go­ing a step fur­ther and ac­ci­den­tally en­gi­neered an en­zyme which was even bet­ter at break­ing down PET plas­tics,” said the re­port in the Pro­ceed­ings of the Na­tional Academy of Sciences, a peer-re­viewed US jour­nal.

Us­ing a su­per-pow­er­ful Xray, 10 bil­lion times brighter than the Sun, they were able to make an ul­tra­high-res­o­lu­tion three-di­men­sional model of the en­zyme.

Sci­en­tists from the Uni­ver­sity of South Florida and the Uni­ver­sity of Camp­inas in Brazil did com­puter mod­el­ing which showed PETase looked sim­i­lar to an­other en­zyme, cuti­nase, found in fun­gus and bac­te­ria.

One area of the PETase was a bit dif­fer­ent, though, and re­searchers hy­poth­e­sized that this was the part that al­lowed it to de­grade man­made plas­tic.—


NONBIODEGRADABLE A Chi­nese la­borer sorts out plas­tic bot­tles for re­cy­cling in Dong Xiao Kou vil­lage, on the out­skirt of Bei­jing.—

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