This is Scientific American 60 Second Science.

I'm Cynthia Graber.

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Genetically engineered bacteria already produced some products of commercial interest

or a biomedical important such as insulin.

And coaxing the organisms to do so can be done with a cleaner setup and produce fewer

fewer environmentally problematic byproducts than other production methods.

But the bacterial approach has stayed limited

to just a few products due to inefficiencies.

Now, a research team at Harvard's Vise Institute

for Biologically-inspired Engineering

says they've developed a system to get microbes to produce chemicals

dramatically faster and more efficiently. The technique uses Darwinian principles

over multiple iterations, what they call rounds of evolution. The study is in the proceedings of the National Academy of Sciences.

The researchers induced mutations in specific genes related to the expression of the desired molecule.

They then tweaked the bacteria so that genes for antibiotic resistance only become active

when the cells make some of the sought after product.

With antibiotics present, cells die that do not produce enough of the product because those cells also do not have the life-saving resistance to the antibiotics.

The surviving cells, however, show promise.

The system takes the cells through this evolutionary cycle repeatedly

eliminating unproductive bacteria each time. The end result, microbes that

synthesize the chemical of interest with 30 times the output of current

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