Pilot-scale production of microbial lipid using starch wastewater as raw material

The aim of this research was to develop a cost-effective pilot-scale fermentation process for lipid production by Rhodotorula glutinis using starch wastewater. A temperature range of 30–37 °C, and an initial chemical oxygen demand (COD) higher than 30,000 mg/L, were optimal for growth and lipid synthesis in flask culture. Cultivation in a 5-L fermenter yielded more than 60 g/L biomass with a 30% (w/w) lipid content after 60 h. Pilot-scale production of microbial lipid in a 300-L fermenter using starch wastewater without sterilization and pH adjustment yielded 40 g/L biomass and 35% lipid content with 80% COD degradation after only 30–40 h of cultivation. Transesterification experiments demonstrated that lipids can be used for biodiesel production.