Bacteria synthesiser

A new method of producing next-generation biofuels makes use of genetically modified Escherichia Coli bacteria.

Researchers at the UCLA Henry Samueli School of Engineering and Applied Science have developed a new method of producing next-generation biofuels by genetically modifying Escherichia Coli (E.Coli) bacteria to make it an efficient biofuel synthesiser.

The method was developed by UCLA Prof of chemical and biomolecular engineering James Liao, postdoctoral fellow Shota Atsumi and visiting Prof Taizo Hanai.

Biofuels, like commercially available ethanol, are produced from agricultural products such as corn, sugarcane or waste cellulose. Ethanol, however, has limitations — it is not as efficient as gasoline and must be mixed with gas for use as a transportation fuel. It also tends to absorb water from its surroundings, making it corrosive and preventing it from being stored or distributed in existing infrastructure without modification.

Higher-chain alcohols have energy densities close to gasoline, are not as volatile or corrosive as ethanol, and do not readily absorb water. Furthermore, branched-chain alcohols, such as isobutanol, have higher-octane numbers, resulting in less knocking in engines. Isobutanol or C5 alcohols have never been produced from a renewable source with yields high enough to make them viable as a gasoline substitute.

The research team modified key pathways in E. coli to produce several higher-chain alcohols from glucose, a renewable carbon source, including isobutanol, 1-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol.

The strategy leverages the E. coli host’s highly active amino acid biosynthetic pathway by shifting part of it to alcohol production. In particular, the research team achieved high-yield, high-specificity production of isobutanol from glucose.

UCLA has now licensed the technology through an exclusive royalty-bearing license to Gevo, a Pasadena, California-based company founded in 2005 and dedicated to producing biofuels.

Liao has joined Gevo’s scientific advisory board. In the role, he will continue to provide technical oversight and guidance during the commercial development of the technology.

The UCLA research was supported in part by the UCLA–Department of Energy Institute for Genomics and Proteomics and the UCLA–NASA Institute for Cell Mimetic Space Exploration.