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 43 mg L−1 h−1 on glucose, and the production rate reached its maximum (3.06 g L−1) after 72 h 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 (56 g L−1). After 165 h of cultivation, cyclopropane fatty acids represented 22% of the lipids produced; cyclopropane fatty acid productivity (103.3 mg L−1 h−1) was maximal at 72.5 h of cultivation.

Lipid Readjustment in Yarrowia lipolytica Odd-Chain Fatty Acids Producing Strains

“…Several engineered strains have been generated to over-accumulate specific fatty acids, such as the high oleic acid producing strains, where oleic acid represents more than 90% of the fatty acids [ 53 ], 6.5% of conjugated linoleic acid [ 54 ], Cyclopropane fatty acids reach 22% [ 55 ], 10-methyl branched fatty acids represent 37% [ 56 ] and odd chain fatty acids content was improved from 46.8% up to 62% [ 1 , 5 ].…”

Microbial valorization of underutilized and nonconventional waste streams

“…Recent literature has shown that oftentimes, the impurities in crude glycerol may be an asset in microbial valorization. For example, the production of cyclopropanated fatty acids from crude glycerol in metabolically engineered Y. lipolytica Po1d showed a 2.4-fold increase in titer (7.5 g/l) relative to pure glycerol (Imatoukene et al., 2020 ). However, the specific effect of potential impurities that may explain this was not studied.…”

Overview of the Cellular Stress Responses Involved in Fatty Acid Overproduction in E. coli

“…2) [49][50][51][52]. When a cell is exposed to acidic or hyperosmotic environment, RpoS induces CFA synthase to cyclise UFA reservoirs into CFA [49,[52][53][54]. CFA synthesis decreases the unsaturation of membranous fatty acid, causing decrease in the membrane fluidity.…”