E. Coli Engineered to Produce High-Volume Biofuel

E coli bacteria magnified (USDA Agricultural Research Service/Wikimedia Commons)

Researchers at University of California in Los Angeles have engineered the bacteria E. coli to produce butanol, a type of alcohol that can substitute directly for gasoline in today’s car motors, and in greater quantities than before. The team published its findings earlier this month in the online edition of the journal Applied and Environmental Microbiology.

Escherichia coli, better known as E. coli, is popularly associated with food contamination, but is also a common laboratory testing medium for biochemists. The UCLA team, led by professor James Liao, constructed a biochemical pathway in E. coli with genetic engineering to produce normal butanol (n-butonal), which E. coli does not produce naturally.

Liao’s team also reengineered the metabolism in E. coli to take advantage of the new biochemical pathway. This metabolic tinkering enabled the UCLA researchers to generate 15 to 30 grams of n-butanol per liter of culture medium. Typical output is 1 to 4 grams of n-butanol per liter.

While the microbe Clostridium can naturally produce n-butanol, it also adds by-products in the process, says Liao. The bio-engineered E. coli at UCLA, on the other hand, does not add by-products, thus reducing likely commercial production costs.

Unlike the alcohol biofuel ethanol, n-butonal can be used directly in today’s internal combustion engines, without making modifications to those engines. It can also use the same transport and storage facilities as gasoline.

The next step in the research, the researchers say, will be for industry to develop a more robust industrial process. The study was funded by the KAITEKI Institute of Japan, a part of Mitsubishi Chemical Holdings Corp.

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