title: Enzymatic conversion of waste cooking oils into alternative fuel--biodiesel.
abstract: Production of biodiesel from pure oils through chemical conversion may not be applicable to waste oils/fats. Therefore, enzymatic conversion using immobilized lipase based on Rhizopus orzyae is considered in this article. This article studies this technological process, focusing on optimization of several process parameters, including the molar ratio of methanol to waste oils, biocatalyst load, and adding method, reaction temperature, and water content. The results indicate that methanol/oils ratio of 4, immobilized lipase/oils of 30 wt% and 40 degrees C are suitable for waste oils under 1 atm. The irreversible inactivation of the lipase is presumed and a stepwise addition of methanol to reduce inactivation of immobilized lipases is proposed. Under the optimum conditions the yield of methyl esters is around 88-90%.
authors.affiliation: Section of Bioenergy and Environment (Faculty of Environmental Science and Engineering)/State Key Lab of Internal Combustion Engine, Tianjin University, 300072 Tianjin, China. chen@tju.edu.cn
authors.forename: Guanyi
authors.initials: G
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Ying
authors.forename: Weizhun
authors.initials: W
authors.lastname: Li
mesh_terms: D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000737:chemistry; D019649:Food Industry; D005742:Gasoline; D007219:Industrial Oils; D007220:Industrial Waste / Q000517:prevention & control*; D010938:Plant Oils / Q000737:chemistry*; D012147:Restaurants; D012233:Rhizopus / Q000201:enzymology*
chemical_list: D004800:Enzymes, Immobilized; D005742:Gasoline; D007220:Industrial Waste; D010938:Plant Oils