Development of an orthogonal fatty acid biosynthesis system in E. coli for oleochemical production.

Here we report recombinant expression and activity of several type I fatty acid synthases that can function in parallel with the native Escherichia coli fatty acid synthase. Corynebacterium glutamicum FAS1A was the most active in E. coli and this fatty acid synthase was leveraged to produce oleochemicals including fatty alcohols and methyl ketones. Coexpression of FAS1A with the ACP/CoA-reductase Maqu2220 from Marinobacter aquaeolei shifted the chain length distribution of fatty alcohols produced. Coexpression of FAS1A with FadM, FadB, and an acyl-CoA-oxidase from Micrococcus luteus resulted in the production of methyl ketones, although at a lower level than cells using the native FAS. This work, to our knowledge, is the first example of in vivo function of a heterologous fatty acid synthase in E. coli. Using FAS1 enzymes for oleochemical production have several potential advantages, and further optimization of this system could lead to strains with more efficient conversion to desired products. Finally, functional expression of these large enzyme complexes in E. coli will enable their study without culturing the native organisms.

Production of anteiso-branched fatty acids in Escherichia coli; next generation biofuels with improved cold-flow properties.

Microbial fermentation is emerging as an increasingly important resource for the production of fatty acids to serve as precursors for renewable diesel as well as detergents, lubricants and other industrial chemicals, as an alternative to traditional sources of reduced carbon such as petroleum. A major disadvantage of fuels derived from biological sources is their undesirable physical properties such as high cloud and pour points, and high viscosity. Here we report the development of an Escherichia coli strain that efficiently produces anteiso-branched fatty acids, which can be converted into downstream products with lower cloud and pour points than the mixtures of compounds produced via the native metabolism of the cell. This work addresses a serious limitation that must be overcome in order to produce renewable biodiesel and oleochemicals that perform as well as their petroleum-based counterparts.