Conversion of raw glycerol to microbial lipids by new Metschnikowia and Yarrowia lipolytica strains

Abstract

Nine Metschnikowia spp. strains and six Yarrowia lipolytica strains were tested for lipid production on raw glycerol from a biodiesel plant. Metschnikowia sp. 271 and Y. lipolytica 347 were selected for biomass and lipid production, and optimized using central composite factorial design (CCD) and response surface methodology (RSM). The lipid production (2.60 g/L) of Y. lipolytica 347 was maximized at C/N 118, time 144 h and 90 g/L glycerol, while the maximum lipid production (0.49 g/L) of Metschnikowia sp. 271 was obtained under similar conditions but after a further incubation for 7 days at 16 °C. The fatty acids profile of Y. lipolytica exhibited a considerable amount of C18:1n7 (~36 %), C18:1n9 (~16 %), and C16:0 (~16 %), whereas Metschnikowia sp. produced mainly C18:1n9 (~33 %), C16:0 (~21 %), and C16:1n7 (~21 %). Both yeasts showed similar amounts of unsaturated fatty acids (~70 %). However, considerable amounts of polyunsaturated fatty acid (PUFAs) were exhibited only by Metschnikowia sp. (~12 %).