研究小组说：“许多染料厂通过将废染料倾倒到河水里避免污水处理的额外费用，从而对河水产生不良的生态影响。”

　　The new method mimics the workings of the Japanese plant Persicaria tinctoria.

　　这种新的方法就是模仿日本蓼蓝植物的工作原理。

　　Instead of a plant, "we engineered a common lab strain of Escherichia coli, a bacteria found in our gut, to be a chemical factory for the production of indigo dye," study co-author John Dueber of the University of California’s bioengineering department told AFP.

　　新方法并不是一种植物。加利福尼亚大学生物工程系的合著者约翰·杜伯告诉法新社说：“我们设计了一种常见的大肠杆菌实验室菌株，这是一种在我们肠道里发现的细菌, 可以成为一个化学工厂，用于生产靛蓝染料。”

　　Like the plant, the bacteria produces a compound called indoxyl, which is insoluble and cannot be used as a dye. By adding a sugar molecule, the indoxyl is turned into indican -- a precursor of indigo.

　　像植物一样, 细菌产生的化合物称为吲哚酚，它不溶于水，不能用作染料。加入糖分子, 吲哚酚就会转化成糖苷——靛蓝前驱体。

　　Indican can be stored and transformed into indigo direcly on the cloth when dyeing, by adding an enzyme to the mix.

　　糖苷可以存储，染色时，可以在混合物中加入一种酶，这样糖苷就可以直接在布料上转化成靛蓝色。

　　The lab is working to make the process commercially feasible, Dueber said.

　　杜伯称，实验室正在努力使这一过程实现商业化。

　　For now, producing five grammes of indigo to colour one pair of jeans would require "several litres of bacteria," he said, and would be more expensive.

　　现在, 生产五克靛蓝色染料来染一条牛仔裤，就需要“数升的细菌”，他说, 牛仔裤以后会更贵。