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科学家合成可分解塑料的“超级酶”,或将引发塑料回收革命

科学家合成可分解塑料的“超级酶”,或将引发塑料回收革命

DAVID MEYER 2020-10-09
这项技术有望彻底解决塑料垃圾日益增多的问题。

2020年8月24日,印度尼西亚中苏拉威西省的帕卢市,重型装备操作人员在卡瓦图纳垃圾填埋场转移垃圾堆。图片来源:BASRI MARZUKI —— NURPHOTO/盖蒂图片社英美两国的研究人员表示,未来几年,或许会有“多种酶混合液”在垃圾回收站开心地啃食塑料。

这项技术能帮助解决塑料垃圾日益增多的问题,因为它可以把塑料恢复到原始结构。不仅如此,它还能提供当前无法实现的新方法,改进塑料回收过程,减少使用化石燃料生产新塑料的需求。但到目前为止,这种技术的降解过程过于缓慢,还无法用于商业用途。

早在2016年,科学家在日本的一家垃圾回收厂内发现了吃塑料的细菌。两年后,英国朴茨茅斯大学(University of Portsmouth)和美国能源部(U.S. Department of Energy)国家可再生能源实验室(National Renewable Energy Laboratory)的研究人员尝试模拟这种细菌中的“PETase”酶,以深入了解它的特性,结果研究人员意外合成了一种突变酶,这种酶降解聚对苯二甲酸乙二酯(PET)塑料的效率更高。PET塑料常被用于生产塑料瓶。

两年后,研究人员有了新的发现。

他们在近期发表的一篇研究报告中表示,突变PETase酶可以与从同一种吃塑料的细菌中发现的另外一种MHETase酶合成。他们发现,这两种酶合成后,降解塑料的速度提高了一倍。如果精心设计两种酶之间的连接方式,降解速度还能提高三倍。

换言之,这种“多种酶混合液”降解塑料的速度是最初发现的突变PETase酶(比正常PETase酶快20%)的6倍。

朴茨茅斯大学教授约翰•莫吉翰在声明中表示:“我们的首批试验显示,两种酶结合的效果更好,所以我们决定将两者连接起来,就像是用一根绳子把两个吃豆人连在一起。英美两国的研究人员为此做了大量工作,但这些努力都是值得的。我们很高兴看到,这种新型嵌合酶降级塑料的速度是自然进化的单独一种酶的三倍,这为我们进一步提升降解速度开辟了新的途径。”

莫吉翰教授告诉《卫报》称,如果学术界能够与法国的Carbios等生物回收公司合作,这项技术将有望在“未来一两年内”实现商业应用。Carbios最近也发现了一种能够快速降解塑料瓶的酶,但这种酶需要在高温环境下才能降解,而新发现的超级酶并没有温度要求。

莫吉翰教授还表示,可以将吃塑料的酶与能够降解天然纤维的酶合并,从而实现聚酯纤维和棉线等混纺织物的回收。目前这种织物仍无法循环利用。(财富中文网)

翻译:刘进龙

审校:汪皓

英美两国的研究人员表示,未来几年,或许会有“多种酶混合液”在垃圾回收站开心地啃食塑料。

这项技术能帮助解决塑料垃圾日益增多的问题,因为它可以把塑料恢复到原始结构。不仅如此,它还能提供当前无法实现的新方法,改进塑料回收过程,减少使用化石燃料生产新塑料的需求。但到目前为止,这种技术的降解过程过于缓慢,还无法用于商业用途。

早在2016年,科学家在日本的一家垃圾回收厂内发现了吃塑料的细菌。两年后,英国朴茨茅斯大学(University of Portsmouth)和美国能源部(U.S. Department of Energy)国家可再生能源实验室(National Renewable Energy Laboratory)的研究人员尝试模拟这种细菌中的“PETase”酶,以深入了解它的特性,结果研究人员意外合成了一种突变酶,这种酶降解聚对苯二甲酸乙二酯(PET)塑料的效率更高。PET塑料常被用于生产塑料瓶。

两年后,研究人员有了新的发现。

他们在近期发表的一篇研究报告中表示,突变PETase酶可以与从同一种吃塑料的细菌中发现的另外一种MHETase酶合成。他们发现,这两种酶合成后,降解塑料的速度提高了一倍。如果精心设计两种酶之间的连接方式,降解速度还能提高三倍。

换言之,这种“多种酶混合液”降解塑料的速度是最初发现的突变PETase酶(比正常PETase酶快20%)的6倍。

朴茨茅斯大学教授约翰•莫吉翰在声明中表示:“我们的首批试验显示,两种酶结合的效果更好,所以我们决定将两者连接起来,就像是用一根绳子把两个吃豆人连在一起。英美两国的研究人员为此做了大量工作,但这些努力都是值得的。我们很高兴看到,这种新型嵌合酶降级塑料的速度是自然进化的单独一种酶的三倍,这为我们进一步提升降解速度开辟了新的途径。”

莫吉翰教授告诉《卫报》称,如果学术界能够与法国的Carbios等生物回收公司合作,这项技术将有望在“未来一两年内”实现商业应用。Carbios最近也发现了一种能够快速降解塑料瓶的酶,但这种酶需要在高温环境下才能降解,而新发现的超级酶并没有温度要求。

莫吉翰教授还表示,可以将吃塑料的酶与能够降解天然纤维的酶合并,从而实现聚酯纤维和棉线等混纺织物的回收。目前这种织物仍无法循环利用。(财富中文网)

翻译:刘进龙

审校:汪皓

A new "enzyme cocktail" could be happily munching plastic at recycling sites within a couple of years, according to British and American researchers.

The technique wouldn't just help to deal with the problem of ever-increasing plastic waste—because it returns the plastic to its original building blocks, it could also improve the recycling process in ways that are currently impossible, reducing the need to make new plastic out of fossil fuels. But until now, the process seemed too slow for commercial viability.

Back in 2016, scientists discovered plastic-eating bacteria at a recycling plant in Japan. Two years later, researchers from the University of Portsmouth in England and the U.S. Department of Energy's National Renewable Energy Laboratory were trying to model the "PETase" enzyme contained in the bacteria to understand it better—and they accidentally engineered a mutant version that was even more efficient at breaking down the polyethylene terephthalate (PET) plastic that is commonly used to make bottles.

Fast-forward another two years, and the researchers have made yet another discovery.

As detailed in a research paper published Monday, the mutant PETase can be combined with another enzyme called MHETase, found in the same trash-dwelling bacterium. It turns out that the simple mixing of the two enzymes doubles the speed of their plastic digestion. And if a connection is engineered between the two enzymes, the digestion is another three times faster.

In other words, this enzyme cocktail can digest plastic up to six times faster than the original mutant PETase (which was itself 20% faster than the natural PETase) can.

"Our first experiments showed that they did indeed work better together, so we decided to try to physically link them, like two Pac-men joined by a piece of string," said University of Portsmouth professor John McGeehan in a statement. "It took a great deal of work on both sides of the Atlantic, but it was worth the effort. We were delighted to see that our new chimeric enzyme is up to three times faster than the naturally evolved separate enzymes, opening new avenues for further improvements."

McGeehan told the Guardian that commercial use could start happening "within the next year or two" if the academics work in partnership with biorecycling firms such as France's Carbios, which recently found an enzyme that quickly digests plastic bottles, but at high temperatures that the new super-enzyme does not require.

The professor also told the newspaper that it might be possible to combine plastic-eating enzymes with those that break down natural fibers, which would allow for the currently impractical recycling of mixed fabrics that include both polyester and cotton.

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