Microbial lipid production by cold‐adapted oleaginous yeast <i>Yarrowia lipolytica</i> B9 in non‐sterile whey medium

Abstract

Abstract Deproteinized whey was used as a substrate for the production of lipids by cold‐adapted yeast Yarrowia lipolytica B9 under non‐sterile culture conditions. Undesired microbial contamination in non‐sterile whey medium could be prevented when appropriate culture parameters (inoculum size of 3 mL /100 mL , initial pH of 5.5 and incubation temperature of 15 °C) were selected. In contrast to additional nitrogen (ammonium sulfate) and phosphorus (potassium dihydrogen phosphate) sources, additional carbon source (lactose) increased lipid accumulation. Under optimized culture conditions, biomass and lipid concentrations of the yeast were found as 7.4 g/L and 4.29 g/L, respectively. Lipid content was determined as 58% of total cell biomass. Fatty acids of the yeast were oleic acid (18:1), cis‐10‐heptadecenoic acid ( C17 :1), palmitoleic acid (16:1) and palmitic acid (16:0). The yeast was found to contain no polyunsaturated fatty acids. The content of C16 and C18 fatty acids was found to be 91.98% of total lipids. Monounsaturated fatty acids accounted for 80.54% of total lipids. Due to rich monounsaturated fatty acid composition, biomass of Y. lipolytica B9 may be used as feedstock for biodiesel production, especially operating in winter conditions. This is the first report on the use of cheese whey as a lipid production substrate for cold‐adapted microorganisms including Y. lipolytica yeast. Besides, lipid production potential of Y. lipolytica under non‐sterile culture conditions was investigated for the first time in this study. © 2015 Society of Chemical Industry and John Wiley &amp; Sons, Ltd