BIODIESEL PRODUCTION FROM WASTE GREASE USING EASILY PREPARED AND RECYCLABLE BIOCATALYSTS

Abstract

Biodiesel is a diesel alternative comprising a mix of fatty acid methyl esters (FAME). It is typically produced from expensive and edible feedstock such as soybean oil, thus there is a need to investigate economical and inedible alternatives for biodiesel production. Waste grease collected from grease traps in sewers has no commercial value and is inedible, thus it could be a useful alternative feedstock for the production of biodiesel. The high content of free fatty acids (FFA) in waste grease makes it unsuitable for biodiesel production using conventional alkali catalysis, but lipases offer a green and efficient solution for this. Different means of biodiesel production from waste grease are investigated using lipases formulated as wet cells, silica gel cells, and immobilised enzymes. Directed evolution of Thermomyces lanuginosus lipase was also carried out to improve its methanol tolerance for biodiesel production. These biocatalysts are recyclable, making them practical for industrial application.