Fermentation process for producing CFAs using Yarrowia lipolytica.

Abstract

Past research has sought to improve the production of cyclopropane fatty acids by the oleaginous yeast Yarrowia lipolytica by heterologously expressing the E. coli fatty acid synthase gene and improving cultivation processes. Cyclopropane fatty acids display properties that hold promise for biofuel applications. The E. coli fatty acid synthase gene was introduced into several genetic backgrounds of the yeast Y. lipolytica to optimize lipid synthesis; the mean cyclopropane fatty acid productivity was 43mg L-1 h-1 on glucose, and the production rate reached its maximum (3.06g L-1) after 72h of cultivation in a bioreactor. The best strain (JMY6851) overexpressed simultaneously the E. coli cyclopropane fatty acid synthase gene under a hybrid promoter (hp8d) and Y. lipolytica LRO1 gene. In fed-batch process using crude glycerol as carbon source, JMY6851 strain displayed high lipid accumulation (78% of dry cell weight) and high biomass production (56g L-1). After 165h of cultivation, cyclopropane fatty acids represented 22% of the lipids produced; cyclopropane fatty acid productivity (103.3mg L-1 h-1) was maximal at 72.5h of cultivation.