Exploiting a Soil Bacterium for the Sustainable Production of High-Value Lipids

As one of the most highly oleaginous microorganisms, rhodococci have considerable potential for the sustainable production of commodity lipids. The soil bacterium Rhodococcus jostii RHA1 accumulates triacylglycerides (TAGs) to up to 70% of its cellular dry weight. Moreover, RHA1 grows on a variety of carbon sources, including many derived from lignocellulosic biomass. This makes RHA1 an excellent candidate for developing microbial biocatalysts to convert biomass waste into high-value lipids. In RHA1, TAGs are synthesized via the Kennedy Pathway. We are studying the genes involved in the different steps of this pathway. Our results provide insight into the roles of genes encoding for putative phosphatidic acid phosphatases, haloacid dehalogenase-type hydrolases, and diacylglycerol acyltransferases. These insights are in turn enabling us to engineer RHA1 to augment lipid accumulation and to alter the kinds of lipids it sequesters. The production of such lipids from lignocellulosic feedstocks offers a sustainable source for consumer products.