A cost efficient way to obtain lipid accumulation in the oleaginous yeast Rhodotorula glutinis using supplemental waste cooking oils (WCO)

The microbial oil from oleaginous Rhodotorula glutinis is considered to be a promising raw material for biodiesel production because it shares a fatty acid composition similar to that of vegetable oil. To enhance lipid accumulation and also reduce production costs, the use of supplemental waste cooking oils (WCO) in the medium as the carbon source was examined. The results indicated that supplemental WCO can enhance cell growth and increase the lipid content as compared to the control batch with crude glycerol only. The average lipid content in the batch with supplemental WCO was 46 +/- 5% as compared to 39 +/- 4% in the control batch with crude glycerol only. Due to a consideration of the immiscibility of WCO in the medium, the provision of higher mixing effects and greater shear force in the agitation tank can enhance the digestion of WCO. The estimated average cell growth rate were found to be 0156 and 0.125 g/L hr in the agitation tank and in the airlift bioreactor, respectively. The supplemental WCO in the agitation tank with crude glycerol was found conclusively to have the potential for being utilized as an efficient way to obtain lipid accumulation in oleaginous R. glutinis. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.