BIO-BASED VALUE-ADDED ALPHA-OLEFINS

Researchers at The Center for Biorenewable Chemicals (CBiRC), an NSF-funded Engineering Research Center headquartered at Iowa State University, recently showed that medium chain length free fatty acids can be produced by E.coli using sugars as the carbon source. The research uses codon-optimized eukaryotic and prokaryotic enzyme sources expressed in the microbial systems. The projects reported 35-40% of the theoretical yields with 2.7g/L being attained, comparing very favorably with recent literature reports. Further improvements are underway with strain optimization, media optimization and fine-tuning of the operating conditions. Similar studies are underway in yeast systems using similar enzyme sources along with additional optimization and characterization. Simultaneously, in parallel research projects the toxicity of such short chain fatty acids is being evaluated. This research combines flux map analysis and newly developed bioinformatic "network component analysis" tools for systemwide analysis and allows insights into the compensatory mechanisms being perturbed in such biological systems.

These studies are enabling CBiRC to drive the construction of its metabolic engineering design engine and hence make new strains for high level fatty acid and polyketide synthesis in microbes. The projects bring together faculty from Iowa State University as well as the University of Califorina - Irvine, Rice University, the Salk Institute and the University of Michigan.

Medium chain fatty acids are important as a stepping stone to creating even shorter fatty acids in the future. These medium and shorter chain fatty acids can form a foundation for making α-olefins using other chemical catalysis methods under development in CBiRC. Such α-olefins are part of the larger family of olefins or alkenes with a chemical formula CxH2x. Polymerization of alkenes yields polymers that are known in a general way as polyolefins. The α-olefins are distinguished by having a double bond at the primary or α-position, which enhances the reactivity of the compound and makes it useful for a number of applications. Olefins are reactive intermediates used to manufacture products used in plastics, lubricants, surfactants, agricultural chemicals, coatings and corrosion inhibitors. Such olefins are synthesized today from petrochemical sources and can have high industrial value. The research reported above begins to set-out a new path to making biorenewable or bio-based olefins.

To learn more about this topic visit: Center for Biorenewable Chemicals (CBiRC)