抄録
Global concern on environmental pollution and threatening depletion of traditional energy resources has promoted the development of new environmental legislations and opened useful insights on research. Reutilization of wastes from diverse origins as renewable energy sources and as raw materials for the synthesis of value-added products is an area of increasing exploitation. In this study we utilized solid wastes (waste activated bleaching earth: WABE) generated from vegetable oil refining industry for production of fatty acid alkyl esters by lipase-catalyzed alcoholysis with primary alcohols in an organic solvent system. Several commercial lipases were screened on their ability to display high activity in organic solvent system. Alcoholysis of WABE containing palm oil with methanol was chosen as model reaction for optimization of enzymatic transesterification. Highest activity was displayed by Candida cylindracea lipase. After 4 hours of reaction more than 78±6% (w/w) fatty acid methyl esters were obtained. Evaluation of lipase activity with linear and branched alcohols showed that C. cylindracea lipase has higher affinity for short alcohols ranging from ethanol to 1-butanol resulting in conversion yields higher than 90±2% (wlw) rather than for short branched and long linear ones. Furthermore, the enzyme displayed high activity in organic solvent only when waste activated bleaching earth was present. Transesterification studies of refined palm oil without activated bleaching earth gave low yields. Highest conversion yields were attained after 8 hours of reaction with 1-butanol, and 96 % (w/w) of butyl palmitate was produced with 4 mole of the alcohol. These results show a promising technique for the production of fatty acid alkyl esters targeted for biodiesel application from industrial waste resources containing vegetable oils.
