Improvement and modeling of culture parameters to enhance biomass and lipid production by the oleaginous yeast Cryptococcus curvatus grown on acetate

Abstract

The improvement of culture parameters for lipid production from acetate as carbon source was investigated using the oleaginous yeast Cryptococcus curvatus. A new pH regulation system dispensing acetate was developed for fed-batch culture and allowed obtaining nearly 80 g/L biomass within 60 h with a maximal growth rate of 0.28 h(-1). A biological model was developed from experimental data. The influence of three C/N ratios of 300, 500 and 900 were tested during a multi-phases process on lipid accumulation. The C/N ratio of 300 was reported to be the most suitable for lipid storage. No significant increase of lipids content was obtained with higher value. A maximal content of 60% DCW of lipid was obtained. The determination of fatty acids profiles of the microbial oils has confirmed that the valorization of acetate by microbial oils production was a promising perspective.

Keywords: Bioconversion; Biodiesel; Cryptococcus curvatus; Microbial lipids; Volatile fatty acids.