Evaluation of lipid synthesis by yeast Candida zeylanoides QU 33 in culture medium with glucose and ammonium sulfate

Abstract

Microbial oil can be considered a source of monounsaturated (MUFAs) and polyunsaturated (PUFAs) fatty acids. Previous research has shown that the yeast Candida zeylanoides QU 33 produces large amounts of MUFAs and PUFAs in culture media containing glucose as carbon source and (NH4)2SO4 as nitrogen source. This study aimed to determine the best parameters for the accumulation of lipids by C. zeylanoides QU 33, knowing that the carbon-to-nitrogen ratio (C:N) in the culture media, as well as pH and temperature, are the parameters that most affect the production of microbial lipids. For optimization, the Response Surface Methodology was applied, using levels of the variables temperature (20-28 ºC), pH (6.0 to 8.0), and glucose concentration (08-20 % w/v). Although no variable showed significant influence, there was a tendency towards lipid accumulation under conditions of high sugar concentrations (above 16%), mid temperatures (23-26º C) and neutral pH.