吃塑料的新科技誕生，雖然不那么有效

The plastic bottles we throw away today will be around forhundreds of years . It's one of the key reasons why the mounting plastic pollution problem, which is having adeadly effect on marine life , is so serious.

我們今天扔掉的塑料瓶會存在幾百年。這是日益嚴重的塑料污染問題，對海洋生物造成嚴重影響的關(guān)鍵原因之一。

But scientistsrecently discovereda strain of bacteria that can literally eat the plastic used to make bottles, and have nowimproved itto make it work faster. The effects are modest – it's not a complete solution to plastic pollution – but it does show how bacteria could help create more environmentally friendly recycling.

但是科學(xué)家們最近發(fā)現(xiàn)了一種細菌，這種細菌可以吃掉用來制造瓶子的塑料，現(xiàn)在他們已經(jīng)對這種細菌進行了改進，使其工作得更快。它的效果并不明顯——這并不是塑料污染的完全解決方案——但它確實表明細菌可以幫助創(chuàng)造更環(huán)保的回收利用。

Plastics are complex polymers, meaning they are long, repeating chains of molecules that don't dissolve in water. The strength of these chains makes plastic very durable and means it takes a very long time to decompose naturally. If they could be broken down into their smaller, soluble chemical units, then these building blocks could be harvested and recycled to form new plastics in a closed-loop system.

塑料是復(fù)雜的聚合物，這意味著它們是長而重復(fù)的分子鏈，不溶于水。這些鏈條的強度使塑料非常耐用，意味著需要很長時間才能自然分解。如果它們能被分解成更小的、可溶的化學(xué)單位，那么這些小分解就能被收集起來，在一個閉環(huán)系統(tǒng)中循環(huán)利用，形成新的塑料。

In 2016,scientists from Japantested different bacteria from a bottle recycling plant and found that Ideonella sakaiensis 201-F6 could digest the plastic used to make single-use drinks bottles, polyethylene terephthalate (PET). It works by secreting an enzyme (a type of protein that can speed up chemical reactions) known as PETase. This splits certain chemical bonds (esters) in PET, leaving smaller molecules that the bacteria can absorb, using the carbon in them as a food source.

2016年，來自日本的科學(xué)家從一個瓶子回收廠檢測了不同的細菌，發(fā)現(xiàn)Ideonella 201-F6可以消化用于制造一次性飲料瓶的塑料——聚對苯二甲酸乙二醇酯(PET)。它的工作原理是分泌一種叫做PETase的酶(一種可以加速化學(xué)反應(yīng)的蛋白質(zhì))。這將分解PET中的某些化學(xué)鍵(酯)，留下細菌可以吸收的小分子，利用其中的碳作為食物來源。

Althoughother bacterial enzymeswere already known to slowly digest PET, the new enzyme had apparently evolved specifically for this job. This suggests it might be faster and more efficient and so have the potential for use in bio-recycling.

盡管已知其他細菌酶可以緩慢地消化PET，但這種新酶顯然是專門為這項工作而進化的。這表明它可能更快、更有效，因此在生物循環(huán)利用方面具有潛力。

As a result, several teams have been trying to understand exactly how PETase works by studying its structure. In the past 12 months, groups fromKorea ,Chinaand theUK, US and Brazilhave all published work showing the structure of the enzyme at high resolution and analysing its mechanisms.

因此，有幾個團隊一直試圖通過研究PETase的結(jié)構(gòu)來確切地了解它是如何工作的。在過去12個月里，來自韓國、中國、英國、美國和巴西的研究小組都發(fā)表了論文，以高分辨率展示了這種酶的結(jié)構(gòu)，并分析了其機理。

These papers show that the part of the PETase protein that performs the chemical digestion is physically tailored to bind to PET surfaces and works at 30°C, making it suitable for recycling in bio-reactors. Two of the teams also showed that by subtly changing the enzyme's chemical properties so it interacted with PET differently made it work more quickly than the natural PETase.

這些論文表明，執(zhí)行化學(xué)消化的PETase蛋白部分是經(jīng)過物理剪裁的，可以與PET表面結(jié)合，并在30°C下工作，適合在生物反應(yīng)器中回收利用。其中兩個研究小組還發(fā)現(xiàn)，通過微妙地改變酶的化學(xué)性質(zhì)，使其與PET發(fā)生不同的相互作用，使其比天然的PETase工作得更快。

Using enzymes from bacteria in bio-reactors to break down plastic for recycling is still easier said than done. The physical properties of plastics make themvery difficultfor enzymes to interact with.

在生物反應(yīng)器中利用細菌的酶分解塑料進行回收，說起來容易做起來難，塑料的物理特性使它們很難與酶相互作用。

The PET used in drinks bottles has a semi-crystalline structure, which means the plastic molecules are tightly packed and difficult for the enzyme to get to. Thelatest studyshows that the enhanced enzyme probably worked well because the part of the molecule that is involved in the reaction is very accessible, making it easy for the enzyme to attack even the buried PET molecules.

用于飲料瓶子的PET具有半晶體結(jié)構(gòu)，這意味著塑料分子被緊密包裹，酶很難到達。最新的研究表明，增強酶可能工作得很好，因為參與反應(yīng)的分子部分是非常容易接近的，使酶很容易攻擊甚至是隱藏的PET分子。