Optimization of Lipid Accumulation by Yarrowia lipolytica Growing on Fermented Food Waste in Two-Stage Batch Strategy

Microbial lipid production by oleaginous yeast applying Food Waste (FW) could be a sustainable alternative for fossil fuels. This study was conducted with the aim of increase cell growth and lipid accumulation of Yarrowia lipolytica under nitrogen deficiency condition. Two-stage batch strategy was conducted using Fermented Food Waste (FFW) at initial stage and three different carbon sources (i.e., glucose, glycerol and potassium acetate) at second stage along with different COD/TKN ratios (i.e., 75, 100, 125, 150 and 175). High lipid content of 42.2 ± 1.72% was obtained in COD/TKN ratio of 125 applying glycerol, with biomass concentration of 12.95 ± 1.95 g/L. Different concentrations and combinations of yeast extract, iron sulfate and trace elements solution were added to the batch cultures with different COD/TKN ratios along with glycerol to furthermore promote biomass concentration and lipid content. The best results were obtained in COD/TKN ratio of 175 supplemented with yeast extract-iron sulfate-trace elements solution, with lipid content of 45.94 ± 0.21%. High biomass concentration of 16.67 ± 0.275 g/L was obtained in the batch culture with same COD/TKN ratio supplemented with yeast extract-trace elements solution. Surface response methodology (SRM) was used to identify the effect of four different variables of glycerol, yeast extract, iron sulfate and trace elements solution on biomass/lipid productivity and biomass/lipid concentration. The study demonstrated the effect of optimized condition to promote lipid accumulation and biomass growth by applying low-cost FFW and glycerol as carbon sources. Stearic acid was the major fatty acid in all microbial lipid fractions. Graphical Abstract: [Figure not available: see fulltext.].