Chemical and biological conversion of crude glycerol derived from waste cooking oil to biodiesel

摘要

Highlights•Crude glycerol was converted to biodiesel by chemical and biological method.•Purified glycerol is a promising carbon source for lipid production from microbe.•The study created a green cycle of crude glycerol application in energy production.AbstractIn this study, crude, purified, and pure glycerol were used to cultivateTrichosporon oleaginosusfor lipid production which was then used as feedstock of biodiesel production. The purified glycerol was obtained from crude glycerol by removing soap with addition of H3PO4which converted soap to free fatty acids and then separated from the solution. The results showed that purified glycerol provided similar performance as pure glycerol in lipid accumulation; however, crude glycerol as carbon source had negatively impacted the lipid production ofT. oleaginosus. Purified glycerol was later used to determine the optimal glycerol concentration for lipid production. The highest lipid yield 0.19g/g glycerol was obtained at 50g/L purified glycerol in which the biomass concentration and lipid content were 10.75g/L and 47% w/w, respectively. An energy gain of 4150.51MJ could be obtained with 1tonne of the crude glycerol employed for biodiesel production through the process proposed in this study. The biodiesel production cost estimated was 6.32US$/gal. Fatty acid profiles revealed that C16:0 and C18:1 were the major compounds of the biodiesel from the lipid produced byT. oleaginosuscultivated with crude and purified glycerol. The study found that purified glycerol was promising carbon source for biodiesel production.