Lipid yields from oleaginous yeasts isolated from the north Peruvian Andes by culture media non-limiting nitrogen

Abstract

Oleochemicals can be obtained from oily yeasts due to their ability to produce a high lipid content. This research aimed to isolate them from the North Peruvian Andes with a lipid content greater than 20%. They were identified by sequencing internal transcribed spacer regions ITS of conserved ribosomal DNA (rDNA), evaluate their growth kinetics, biomass and lipid yields, using culture media with C/N 100:1+xylose (MS-1-7) and 2:1+glucose (MS-2-7). Growth kinetics up to the maximum stationary phase was evaluated using the parameterized Gompertz type II model. Rhodotorula glutinis, R. mucilaginosa, and R. kratochvilovae were selected. The C/N ratio in the culture medium influenced growth kinetics, biomass and lipids yields. With MS-1-7, a high specific growth rate (?max) was obtained, reaching the stationary phase between 6 to 9 h and the highest lipid accumulation between 23.1% and 31.5%. With the MS-2-7 medium, maximum biomass value obtained in the stationary phase between 37 and 51 h, which generated the highest biomass yields at the end of the entire process and lipid yield of 4.65, 5.59, and 8.80 g L-1 in the strains mentioned. There is potential to obtain high lipid yields using a culture media non-limiting nitrogen, examining not only the C/N ratio. But also, the quantities, nature of the components, and type of oleaginous yeasts taking care to avoid a high carbon concentration to prevent the Cabtree effect.