Biodiesel Production from Waste Cooking Oils by Using Immobilized Microorganisms as Whole Cell Catalysts
The main hurdle to the commercialization of lipase-catalyzed production of biodiesel is the cost of enzyme and feedstock oil. In order to reduce the cost of biodiesel production, the lipase-producing whole cells ofAspergillus nigerand immobilized onto biomass support particles (BSPs) were used for the production of biodiesel from waste cooking oil. This article studies this technological process, focusing on optimization of several process parameters, including the water content, catalyst loading and molar ratio of methanol to waste cooking oil. The results indicate that the water content of 20%(based on oil weight), BSPs-immobilized cell catalysts of 6% and methanol/oil molar ratio of 4:1 are the optimum conditions for biodiesel production from waste cooking oil. Under the optimum conditions, the maximum methyl ester (ME) content in the reaction mixture reaches 84.7 wt.% after 72 h. In addition, the whole-cell biocatalysts showed excellent reusability, retaining 73% productivity after 6 batches. Our results suggest that whole-cell A. niger immobilized on BSP is a promising biocatalyst for biodiesel production from waste cooking oil.