The smallest solution to one of our biggest problems - Tierney Thys & Christian Sardet

424,912 views ・ 2022-07-07

TED-Ed


请双击下面的英文字幕来播放视频。

翻译人员: Siyu Lian 校对人员: Yip Yan Yeung
00:11
At this very moment, almost everything around you is being eaten.
0
11090
4588
此时此刻,几乎所有 你身边的东西都在被吃掉。
00:15
Invisible to the naked eye, organisms called microbes swarm every surface.
1
15762
5839
人眼不可见的微生物 聚集在各个角落,
00:21
Hordes of bacteria, archaea, and fungi have evolved to produce powerful enzymes
2
21893
6131
成群的细菌、古菌和真菌已经 进化到可以产生强大的酶,
00:28
that break down tough organic material into digestible nutrients.
3
28024
4755
能够将坚韧的有机物转化为 可消化的营养物质。
00:33
But there’s one particularly widespread type of material
4
33196
3545
但有一种极为常见的材料
00:36
that almost no microbes can biodegrade:
5
36741
3086
几乎没有微生物可以降解:
00:39
plastics.
6
39827
1418
塑料。
00:41
To make most plastics, molecules from oil, gas and coal are refined
7
41245
5548
大多数塑料是由来自石油、 天然气和煤炭的分子经过提炼
00:46
and turned into long, repeating chains called polymers.
8
46793
4546
变成被称为聚合物的长链制成的。
00:51
This process often requires temperatures above 100˚C, incredibly high pressure,
9
51714
6590
这个过程通常需要高于 100 摄氏度的温度、
00:58
and various chemical modifications.
10
58304
2920
极高的压力和各种化学改造。
01:01
The resulting man-made polymers are quite different
11
61682
3212
由此产生的人造聚合物与
01:04
from the polymers found in nature.
12
64894
2002
大自然中的聚合物相当不同。
01:06
And since they’ve only been around since the 1950s,
13
66896
3545
由于塑料在 1950 年才出现,
01:10
most microbes haven’t had time to evolve enzymes to digest them.
14
70441
5297
大部分微生物还没有进化出 可以降解塑料的酶。
01:16
Making matters even more difficult,
15
76114
2127
更加难办的是,
01:18
breaking most plastics’ chemical bonds requires high temperatures
16
78241
4546
破坏大多数塑料的化学键需要
01:22
comparable to those used to create them—
17
82787
2502
与制成它们所用温度相当的高温,
01:25
and such heat is deadly to most microbes.
18
85289
3087
但这样的高温对大多数 微生物来说是致命的。
01:28
This means that most plastics never biologically degrade—
19
88835
4254
这代表了大多数塑料永远 不会被生物降解,
01:33
they just turn into countless, tiny, indigestible pieces.
20
93089
4212
它们只是变成了无数个 无法消化的小碎片。
01:37
And pieces from the most common plastics like Polyethylene, Polypropylene,
21
97593
5214
这些来自常见塑料的碎片, 像是聚乙烯、聚丙烯和
01:42
and Polyester-terephthalate have been piling up for decades.
22
102807
4629
聚对苯二甲酸乙二酯(PET) 几十年来一直堆积着。
01:48
Each year humanity produces roughly 400 million more tons of plastic,
23
108813
5797
每一年人类产生大约 4 亿多吨的塑料,
01:54
80% of which is discarded as trash.
24
114610
3295
其中 80% 被作为垃圾丢弃。
01:58
Of that plastic waste, only 10% is recycled.
25
118197
4171
在所有的塑料垃圾里, 只有 10% 被回收,
02:02
60% gets incinerated or goes into the landfills,
26
122577
3920
60% 的垃圾被焚烧 或进入垃圾填埋场,
02:06
and 30% leaks out into the environment
27
126497
3212
还有 30% 泄漏到环境中
02:09
where it will pollute natural ecosystems for centuries.
28
129709
3795
并污染了自然生态系统 长达几个世纪之久。
02:13
An estimated 10 million tons of plastic waste end up in the ocean each year,
29
133671
6089
每年预计有 1000 万吨 塑料垃圾最终流入海洋,
02:19
mostly in the form of microplastic fragments that pollute the food chain.
30
139760
4964
大多数以微塑料碎片的形态 污染食物链。
02:25
Fortunately, there are microbes that may be able
31
145224
3253
幸运的是,可能有微生物能够
02:28
to take a bite out of this growing problem.
32
148477
2753
“吃”掉一部分 这个日益严重的塑料问题。
02:31
In 2016, a team of Japanese researchers sampling sludge
33
151439
4880
2016 年,一个日本研究小组
02:36
at a plastic-bottle recycling plant discovered
34
156319
3003
在一家塑料瓶回收站 对沉积物进行采样,
02:39
Ideonella sakaiensis 201-F6.
35
159322
4379
他们发现了大阪堺菌 (Ideonella sakaiensis 201-F6)。
02:43
This never-before-identified bacterium contained two enzymes
36
163951
4838
这个前所未见的细菌
02:48
capable of slowly breaking down PET polymers
37
168789
4380
拥有两种可以在相对低温下
02:53
at relatively low temperatures.
38
173169
2169
缓慢破坏PET聚合物的酶。
02:55
Researchers isolated the genes coding for these plastic-digesting enzymes,
39
175504
5047
研究人员分离出了这些 消化塑料酶的基因代码,
03:00
allowing other bioengineers to combine and improve the pair—
40
180551
4713
使其他生物工程家能够 结合并改进这对酶,
03:05
creating super-enzymes that could break down PET up to 6 times faster.
41
185264
5839
从而创造出可以将PET分解 速度提高 6 倍的超级酶。
03:11
Even with this boost,
42
191687
1627
即使有了这样的增强,
03:13
these lab-grown enzymes still took weeks to degrade a thin film of PET,
43
193314
5923
这些实验室培养的酶降解一层 薄薄的PET膜仍需数周,
03:19
and they operated best at temperatures below 40˚C.
44
199237
4212
它们在低于 40˚C 的温度下 工作效果最好。
03:23
However, another group of scientists in Japan had been researching
45
203950
3837
日本的另一组科学家们一直
03:27
bacterial enzymes adapted to high temperature environments
46
207787
4087
在研究让细菌酶适应高温环境,
03:31
like compost piles.
47
211874
1752
如堆肥。
03:34
And within one particularly warm pile of rotting leaves and branches,
48
214001
4922
在一堆特别暖和的腐烂 树叶和树枝中,
03:38
they found gene sequences for powerful degrading enzymes
49
218923
4254
他们发现了拥有强大 降解能力酶的基因代码,
03:43
known as Leaf Branch Compost Cutinases.
50
223177
3420
被称作叶枝复合肥切割酶 (Leaf Branch Compost Cutinases)。
03:47
Using fast-growing microorganisms,
51
227098
2586
利用快速生长的微生物,
03:49
other researchers were able to genetically engineer
52
229684
3128
其他研究人员能够使用基因工程
03:52
high quantities of these enzymes.
53
232812
2294
来产生高数量的酶。
03:55
They then enhanced and selected special variants of the Cutinases
54
235106
3879
他们加强并选择能够在温度 达到 70˚C 的环境中
03:58
that could degrade PET plastic in environments reaching 70˚C—
55
238985
5297
降解PET塑料的特殊变种 角蛋白酶。
04:04
a high temperature that can weaken PET polymers and make them digestible.
56
244282
4796
这样的高温能够削弱PET聚合物 并让它们能够被降解。
04:09
With the help of these and other tiny diehards,
57
249245
3462
有这些和其他小强硬派的帮助,
04:12
the future of PET recycling looks promising.
58
252707
3461
回收PET的未来变得充满希望。
04:16
But PET is just one type of plastic.
59
256252
3295
但PET只是塑料的一类,
04:19
We still need ways to biologically degrade all the other types,
60
259922
4463
我们还需要找到其他办法来 生物降解所有类型的塑料,
04:24
including abundant PEs and PPs
61
264385
3295
包括大量的PE和PP,
04:27
which only begin breaking down at temperatures well above 130˚C.
62
267680
6173
它们在高达 130˚C 以上的温度才开始瓦解。
04:33
Researchers don’t currently know of any microbes or enzymes
63
273978
4421
研究人员现在还没有找到任何
04:38
tough enough to tolerate such temperatures.
64
278399
2836
强大到可以忍耐如此 高温的微生物或酶。
04:41
So for now, the main way we deal with these plastics
65
281902
3129
所以现在我们处理 这些塑料的主要方式是
04:45
is through energy-intensive physical and chemical processes.
66
285031
4170
通过高耗能的物理和化学手段。
04:49
Today only a small fraction of plasticwaste
67
289493
2837
目前只有很小一部分的塑料垃圾
04:52
can be biologically degraded by microbes.
68
292330
2961
可以被微生物生物降解。
04:55
Researchers are looking for more heat-tolerant plastivores
69
295374
3504
研究人员正在地球最恶劣的环境中
04:58
in the planet’s most hostile environments
70
298878
2377
寻找更多耐高温的食塑料者,
05:01
and engineering better plastivorous enzymes in the lab.
71
301255
3837
并在实验室中研制出 更好的食塑料酶。
05:05
But we can’t rely solely on these tiny helpers to clean up our enormous mess.
72
305593
5839
但我们不能单单依靠这些小助手 来清理我们庞大的垃圾堆。
05:12
We need to completely rethink our relationship with plastics,
73
312350
3712
我们需要重新思考 我们和塑料的关系,
05:16
make better use of existing plastics,
74
316520
2878
更好地使用已经存在的塑料,
05:19
and stopproducing more of the same.
75
319982
2795
并停止生产更多已有的塑料制品。
05:23
And we urgently need to design more environmentally friendly types of polymers
76
323486
5297
我们急需设计出更好的, 对环境无害的聚合物,
05:29
that our growing entourage of plastivores can easily break down.
77
329408
4630
让我们持续壮大的食塑料酶 伙伴可以轻松地分解它们。
关于本网站

这个网站将向你介绍对学习英语有用的YouTube视频。你将看到来自世界各地的一流教师教授的英语课程。双击每个视频页面上显示的英文字幕,即可从那里播放视频。字幕会随着视频的播放而同步滚动。如果你有任何意见或要求,请使用此联系表与我们联系。

https://forms.gle/WvT1wiN1qDtmnspy7