Yeast lipid metabolism at a glance

Abstract

During the last decades, lipids have gained much attention due to their involvement in health and disease. Lipids are required for the formation of membranes and contribute to many different processes such as cell signaling, energy supply, and cell death. Various organelles such as the endoplasmic reticulum, mitochondria, peroxisomes, and lipid droplets are involved in lipid metabolism. The yeast Saccharomyces cerevisiae has become a reliable model organism to study biochemistry, molecular biology, and cell biology of lipids. The availability of mutants bearing defects in lipid metabolic pathways and the ease of manipulation by culture conditions facilitated these investigations. Here, we summarize the current knowledge about lipid metabolism in yeast. We grouped this large topic into three sections dealing with (1) fatty acids; (2) membrane lipids; and (3) storage lipids. Fatty acids serve as building blocks for the synthesis of membrane lipids (phospholipids, sphingolipids) and storage lipids (triacylglycerols, steryl esters). Phospholipids, sterols, and sphingolipids are essential components of cellular membranes. Recent investigations addressing lipid synthesis, degradation, and storage as well as regulatory aspects are presented. The role of enzymes governing important steps of the different lipid metabolic pathways is described. Finally, the link between lipid metabolic and dynamic processes is discussed.

Overproduction and secretion of free fatty acids through disrupted neutral lipid recycle in Saccharomyces cerevisiae

“…In S. cerevisiae, unsaturated fatty acids, such as oleic acid, with the double bond between C 9 and C 10 , can be fully oxidized only in the presence of these auxiliary enzymes (Kohlwein et al, 2013). Typically, 80% of yeast fatty acids are monounsaturated with oleic acid being a major fatty acid product (Klug and Daum, 2014;Tehlivets et al, 2007). In addition, to degrade cis or trans double bonds at odd-numbered positions, or cis double bonds at even-numbered positions, auxiliary enzymes are mandatory and some fatty acids, such as petroselinic acid, bypass Pox1 completely and instead get shuttled directly to Fox2, the second-step enzyme involved in FA degradation (Hiltunen et al, 2003).…”

Fatty Acid-Derived Biofuels and Chemicals Production in Saccharomyces cerevisiae

“…Triacylglycerols (TAGs), which can accumulate to very high levels in eukaryotic cells, play an essential role in energy storage (Sorger and Daum, 2003; Klug and Daum, 2014). Wild-type S. cerevisiae strains typically do not accumulate storage lipids to more than 10% dry cell weight (DCW), whereas some oleaginous yeasts and fungi can accumulate TAGs to much higher levels (Li et al, 2007).…”

Conversion of cellulosic materials into glycolipid biosurfactants, mannosylerythritol lipids, by Pseudozyma spp. under SHF and SSF processes

“…The carbon chain length pattern of MEL acyl groups was similar to that found when sugars (hexoses and pentoses) or fatty acid methyl ester C18:0 were used as substrates [3,19]. This suggests that the building blocks of MEL lipidic chains are obtained from a partial β-oxidation of fatty acids, usually accumulated in the form of triglycerides (C16-C18) [20,35]. Accordingly, with this putative metabolic pathway, when Avicel® cellulose is used as substrate, sugars made available for cultivation are partially converted into fatty acids (mainly C18:n) and then, after an incomplete β-oxidation, the shorter acyl groups (C8-C12) are assembled to the sugar moiety (mannosylerythritol) for MEL production [20,36].…”