吃塑料的新科技诞生，虽然不那么有效
我们今天扔掉的塑料瓶会存在几百年。这是日益严重的塑料污染问题，对海洋生物造成严重影响的关键原因之一。
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.
但是科学家们最近发现了一种细菌，这种细菌可以吃掉用来制造瓶子的塑料，现在他们已经对这种细菌进行了改进，使其工作得更快。它的效果并不明显——这并不是塑料污染的完全解决方案——但它确实表明细菌可以帮助创造更环保的回收利用。
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.
塑料是复杂的聚合物，这意味着它们是长而重复的分子链，不溶于水。这些链条的强度使塑料非常耐用，意味着需要很长时间才能自然分解。如果它们能被分解成更小的、可溶的化学单位，那么这些小分解就能被收集起来，在一个闭环系统中循环利用，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，来自日本的科学家从一个瓶子回收厂检测了不同的细菌，发现Ideonella 201-F6可以消化用于制造一次性饮料瓶的塑料——聚对苯二甲酸乙二醇酯(PET)。它的工作原理是分泌一种叫做PETase的酶(一种可以加速化学反应的蛋白质)。这将分解PET中的某些化学键(酯)，留下细菌可以吸收的小分子，利用其中的碳作为食物来源。
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.
尽管已知其他细菌酶可以缓慢地消化PET，但这种新酶显然是专门为这项工作而进化的。这表明它可能更快、更有效，因此在生物循环利用方面具有潜力。
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，有几个团队一直试图通过研究PETase的结构来确切地了解它是如何工作的。在过去12个月里，来自韩国、中国、英国、美国和巴西的研究小组都发表了论文，以高分辨率展示了这种酶的结构，并分析了其机理。
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.
这些论文表明，执行化学消化的PETase蛋白部分是经过物理剪裁的，可以与PET表面结合，并在30°C下工作，适合在生物反应器中回收利用。其中两个研究小组还发现，通过微妙地改变酶的化学性质，使其与PET发生不同的相互作用，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.
在生物反应器中利用细菌的酶分解塑料进行回收，说起来容易做起来难，塑料的物理特性使它们很难与酶相互作用。
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.
用于饮料瓶子的PET具有半晶体结构，这意味着塑料分子被紧密包裹，酶很难到达。最新的研究表明，增强酶可能工作得很好，因为参与反应的分子部分是非常容易接近的，使酶很容易攻击甚至是隐藏的PET分子。
