Modulation of saturation and chain length of fatty acids in Saccharomyces cerevisiae for production of cocoa butter‐like lipids

Abstract

Chain length and degree of saturation plays an important role for the characteristics of various products derived from fatty acids, such as fuels, cosmetics, and food additives. The seeds of Theobroma cacao are the source of cocoa butter, a natural lipid of high interest for the food and cosmetics industry. Cocoa butter is rich in saturated fatty acids that are stored in the form of triacylglycerides (TAGs). One of the major TAG species of cocoa butter, consisting of two stearic acid molecules and one oleic acid molecule (stearic acid-oleic acid-stearic acid, sn-SOS), is particularly rare in nature as the saturated fatty acid stearic acid is typically found only in low abundance. Demand for cocoa butter is increasing, yet T. cacao can only be cultivated in some parts of the tropics. Alternative means of production of cocoa butter lipids (CBLs) are, therefore, sought after. Yeasts also store fatty acids in the form of TAGs, but these are typically not rich in saturated fatty acids. To make yeast an attractive host for microbial production of CBLs, its fatty acid composition needs to be optimized. We engineered Saccharomyces cerevisiae yeast strains toward a modified fatty acid synthesis. Analysis of the fatty acid profile of the modified strains showed that the fatty acid content as well as the titers of saturated fatty acids and the titers of TAGs were increased. The relative content of potential CBLs in the TAG pool reached up to 22% in our engineered strains, which is a 5.8-fold increase over the wild-type. SOS content reached a level of 9.8% in our engineered strains, which is a 48-fold increase over the wild type.

Identification of genes involved in shea butter biosynthesis from Vitellaria paradoxa fruits through transcriptomics and functional heterologous expression

“…Further heterologous expression of GPAT, LPAT, and DGAT genes in yeast identified several functional shea tree TAG biosynthetic genes. As yeast can be modulated for SOS lipid production and reprogramming of cellular metabolism pathway could turn S. cerevisiae to an oleaginous yeast (Bergenholm et al 2018 ; Yu et al 2018 ), further expression of the identified TAG biosynthetic genes in the engineered yeast might be used for microbial SOS (shea butter) production.…”

Expressing a Cytosolic Pyruvate Dehydrogenase Complex to Increase Free Fatty Acid Production in Saccharomyces Cerevisiae

“…These changes might be because of the PDH complex with excess NADH produced and its consistent activity under high NADH/NAD + ratios. The PDH complex may be a potential target to increase the unsaturation of the FFAs and their derivatives, besides manipulations on Delta-9 fatty acid desaturase OLE1 reported to control the fatty acid saturation in previous studies [40,41].…”

SLIMEr: probing flexibility of lipid metabolism in yeast with an improved constraint-based modeling framework

“…Finally, we have demonstrated the use of the expanded model as a tool to compute lipid requirements in varying experimental conditions. We expect the enhanced model to be very useful for metabolic engineering applications, particularly for designing strains that can rearrange the chain length distribution of specific lipid classes (Bergenholm et al, 2018).…”