Genetic Strategies on Kennedy Pathway to Improve Triacylglycerol Production in Oleaginous Rhodococcus Strains

Abstract

During the last years, microorganisms (yeasts, fungi, microalgae and bacteria) have been receiving increasing attention as alternative lipid sources (also called single cells oils). Some lipid-accumulating bacteria, in particular those belonging to actinomycetes, are able to synthesize remarkably high amounts of triacylglycerides (TAG) (up to 70% of the cellular dry weight) from simple carbon sources such as glucose, which are accumulated as intracellular lipid bodies. The applied potential of bacterial TAG may be similar to that of vegetable oils sources, such as additives for feed, cosmetics, oleochemicals, lubricants and other manufactured products. In addition, bacterial oils have been recently considered as alternative sources for biofuel production. Because the development of an industrial and commercially significant process depends on the optimization of engineered cells and the technological procedures, several efforts to improve the natural accumulation of microbial lipids have been performed around the world. This chapter focuses on some genetic strategies for improving TAG accumulation in bacteria using oleaginous Rhodococcus strains as model. Particularly, protocols focus on the two last enzymatic steps of the Kennedy pathway by overexpression of ro00075 gene and 2 atf genes coding for a phosphatidic acid phosphatase type 2 (PAP2) and diacylglycerol-acyltransferases (WS/DGAT) enzymes, respectively.