Optimization of the biomass production of oil algae Chlorella minutissima UTEX2341

► Glycerin and casein were the best for algae UTEX2341 biomass and lipid production. ► Biomass and lipid yields were 28.7 and 11.9 times higher than that by Illman and Oh. ► The unsaturated fatty acids were the main parts of FAME. ► 94% of the fatty acid was composed of the palmitic, oleic, linoleic and γ linoleic. High production cost is a major obstacle to the extensive use of microalgae biodiesel. To cut the cost and achieve higher biomass productivity, Chlorella minutissima UTEX2341 was cultured under photoheterotrophic conditions. With the carbon, nitrogen and phosphorus concentration of 26.37, 2.61 and 0.03gL−1d−1 respectively, a maximum biomass productivity of 1.78gL−1d−1 was obtained, which was 59 times more than that cultured under autotrophic condition. The lipid productivity reached 0.29gL−1d−1, which was 11.9 times higher than the highest value reported by Oh et al. (2010). The conversion rate of microalgae lipids to FAME was found to be elevated from 45.65% to 62.97% and the FAME productivity increased from 1.16 to 180.68mgL−1d−1 after the optimization. 94% of the fatty acid of C. minutissima UTEX2341 was found to be composed of palmitic, oleic, linoleic and γ linoleic and the unsaturated fatty acids were the main parts (79.42%).