Sci­ence worth chew­ing on

The Citizen-Record (Cumberland) - - COVER STORY - Rus­sell Wanger­sky Rus­sell Wanger­sky’s col­umn ap­pears in 39 SaltWire news­pa­pers and web­sites in At­lantic Canada. He can be reached at rus­sell. wanger­sky@thetele­gram.com — Twit­ter: @ wanger­sky.

Na­ture will find a way, even when it changes to deal with pol­lu­tion.

It just may not be the way we want or ex­pect.

It’s early days yet, but sci­en­tists are tin­ker­ing with bac­te­ria that may be able to help deal with one of the largest pol­lu­tion prob­lems we face now: what to do with poly­eth­yl­ene tereph­tha­late (PET) plas­tics. The sci­en­tists were work­ing with Ideonella sakaien­sis, a bac­terium that was dis­cov­ered at a bot­tle re­cy­cling fa­cil­ity in Ja­pan that “eats” PET plas­tics (if your plas­tic bot­tle has the nu­meral 1 in­side its re­cy­cling tri­an­gle, it’s PET.)

Savour that sweet, sweet con­cept for a few mo­ments: what bet­ter place could there be for a plas­tic-eat­ing bac­te­ria to de­velop than at a re­cy­cling fa­cil­ity? Af­ter all, there’s food all around, if plas­tic be­comes your thing. (It’s also apt from the point of view of the good old Ja­panese mon­ster movie, but more on that in a minute.)

We’ve heard about biodegrad­able plas­tics be­fore, but things like “biodegrad­able” plas­tic bags re­ally aren’t: they’re sim­ply made with enough plant starches to al­low them to break down into bits of plas­tic too small to see. But the plas­tics are still there.

Ideonella sakaien­sis, though, is dif­fer­ent. It pro­duces both en­ergy and car­bon from PET us­ing two en­zymes, and breaks the plas­tic down into eth­yl­ene gly­col and tereph­thalic acid. As sci­en­tists ex­per­i­mented with the en­zymes, they made a stronger, im­proved ver­sion — some­thing that was in the news this week.

I know, I like sci­ence fic­tion far too much. But I do know that, for ev­ery ac­tion, there’s an equal and op­po­site re­ac­tion. That na­ture ab­hors a vac­uum. That noth­ing is con­stant but change.

And I kind of won­der what would hap­pen if a bac­terium amped up with a su­per-PET-dis­solv­ing en­zyme ac­tu­ally got loose in the world, and started chow­ing down on one of our most use­ful (as well as waste­ful) poly­mers.

Af­ter all, when PET is used in cloth­ing, it’s known as polyester — some­thing that hangs in a fair num­ber of peo­ple’s clos­ets. Even if your clothes aren’t made of the fi­bres, they may be sewn to­gether — or have their but­tons at­tached — with polyester thread. Close to 60 per cent of PET pro­duc­tion ends up in cloth­ing, and 30 per cent in bot­tles. Other uses in­clude ev­ery­thing from coat­ings used in so­lar pan­els to man­u­fac­tur­ing ap­pli­ca­tions. And imag­ine if a mod­est col­lec­tion of PET-munch­ing bac­te­ria found their way into the load­ing dock of your favourite soda bot­tler. The re­sults, af­ter a while, might be, well, fizzy. All of this, of course, is a long, long way into the fu­ture. The race now is to see if the en­zymes can work in an in­dus­trial set­ting to break down the plas­tic. (And, it should be pointed out, the bac­te­ria in­volved can eat the plas­tics, but it’s not clear if the ma­te­rial would be a favourite choice, if other foods were avail­able.)

Over­all, though, find­ing a new and in­ven­tive so­lu­tion for pop­u­la­tion that ab­solves us of our slovenly way runs the risk of cre­at­ing its own, as-yet-un­con­sid­ered prob­lems. Is it an im­prove­ment, for ex­am­ple, if the plas­tic in our oceans was to be re­placed with eth­yl­ene gly­col (also known as an­tifreeze) and tereph­thalic acid (which has re­pro­duc­tive im­pacts and can help some uri­nary tract can­cers de­velop more quickly)?

That’s why the early stages of a sci­en­tific process of­ten re­mind me of the old song that starts, “I know an old lady who swal­lowed a fly.”

I’ve said this be­fore about other things: the so­lu­tion may have worked for each step along the way, but the old lady died.

A plas­tic-eat­ing mi­crobe? Maybe a dou­ble-edged sword.

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