Investigating the concomitant production of carotenoids and lipids by the yeast Rhodosporidium babjevae using sugarcane bagasse hydrolysate or corn steep liquor

Abstract

The yeast Rhodosporidium babjevae was used to produce carotenoids, lipids, and fatty acids using sugarcane bagasse hydrolysates or glucose. Investigating the impact of glucose concentrations (10–150 g/L), the yeast showed the capability to yield 16.9 g/L biomass and 10.5 g/L lipids at 60 g glucose/L, while the highest pigments concentration (312 μg/g) was observed at 10 g glucose/L. Pre-treatment methods, including organosolv (ethanol 60 %(w/w)), alkali (NaOH 2 %(w/v)) and alkaline-organosolv (ethanol 60 %(w/w) and NaOH 2 %(w/v)) were used on the sugarcane bagasse following enzymatic hydrolysis. Among these, alkaline organosolv pre-treatment exhibited the most effective lignin removal of 81.9 %, releasing 46.7 g/L sugars by hydrolysis. Yeast cultivation on the enzymatic hydrolysates of alkaline organosolv pre-treatment resulted in the highest biomass (9.6 g/L) and lipids (5.0 g/L) yields. However, the highest content of pigments (280 μg/g) was achieved when the yeast was cultivated on the enzymatic hydrolysates of organosolv pre-treatment. Production of 11.3 g/L biomass, 204 μg/g pigments, and 6.7 g/L lipids established that corn steep liquor holds potential as a cheap and viable alternative to yeast extract as nitrogen source. The analysis of fatty acid composition revealed the prevalence of oleic acid and linoleic acid as dominant components.