Establishment of a New Genetic Transformation System and Its Application for Genetic Engineering on Lipid Production in the Oleaginous Yeast Lipomyces starkeyi

Abstract

Oleaginous microorganisms ranging from yeast, molds, and algae to bacteria have the ability to accumulate lipid to the levels greater than 20% of their biomass. Some yeasts, such as Lipomyces starkeyi, Rhodosporidium toruloides, and Rhodotorula glutinis, can accumulate lipids in their cells in the form of triacylglycerols (TAGs) to more than 65% of their cell dry weight. L. starkeyi is one of the most known oleaginous microorganisms and is able to accumulate up to 72.3% of dry cell weight as TAG. Thus, L. starkeyi is a unique yeast species of great industrial potential as an excellent lipid producer. Recently, the genome sequence of L. starkeyi was revealed and many functional genes are expected to be analyzed. Genetic and metabolic engineering of L. starkeyi via gene-manipulation techniques may result in improved lipid production and also understanding of the mechanisms responsible for lipid droplet formation and lipid biosynthesis pathways. However, such methods for molecular breeding have not been established for L. starkeyi. This review describes the lipid production and the development of an integrative transformation system, a highly efficient gene-targeting system, and a multicopy-integration system in L. starkeyi. Furthermore, we also describe about the possible usage toward engineering of lipid production with new features.