Aspergillus niger based lipase-tween 80 aggregates as interfacial activated biocatalyst for biodiesel production: Optimization using response surface methodology

Abstract

Biodiesel is a renewable energy source, which is produced through transesterification reactions. Despite great attention to develop enzymatic biodiesel production, there are serious obstacles to the industrial development of it such as its cost and slow reaction rate. Along with disadvantages, there are several advantages for enzymatic biodiesel production. Higher purity of fuel and glycerol is known as the most important achievement of enzymatic process. In this study, performance of four different fungi for lipase production was investigated and Aspergillus niger was selected as enzyme source. Lipase production were optimized using experimental design and the optimized factors were determined as pH 5, temperature 30 °C, Potato Dextrose Broth (PDB) 3 % w/v, olive oil 1.50 % v/v, with maximum lipase activity of 42.8±0.51 U/mg. In order to interfacial activation of the lipase, effect of surfactants was studied. Therefore, surfactant-enzyme aggregates were used as biocatalyst for transesterification reaction. Effects of factors on biodiesel yield were studied too. The yield was 96.41±1.20 % at the optimized conditions (methanol/oil molar ration 5.50:1, enzyme concentration 19 % v/ w, Tween 80 concentration 19 mg L^–1, temperature 40 °C and reaction time 46 h).