Lipolytic bacterial strains mediated transesterification of non-edible plant oils for generation of high quality biodiesel

Abstract

Biodiesel is one of the best alternative to depleting fossil fuels for transport sector. However, biodiesel production via lipase mediated transesterification has limitation of high costing microbial enzymes. In order to overcome this limitation, a process of sequential treatment of oil industry wastewater using isolated lipolytic bacterial strains and biodiesel production from non-edible plant oils was studied. In this study, efficient lipase producing bacteria were isolated and evaluated for production of biodiesel from mustard, soybean, jatropha and taramira oils utilizing methanol for the transesterification of oils and bioremediation. Selected strains were then identified, using 16s rRNA sequencing. Further, Bacillus subtilis strain Q1 KX712301 was optimized for biodiesel production from non-edible taramira oil via Plackett-Burman and central composite design. Highest volumetric yield of biodiesel obtained was 102% at optimized parameters. Finally, a sequential bioremediation of vegetable oil contaminated wastewater and then microbial production of biodiesel from non-edible taramira oil was carried out using efficient lipase producer B.subtilis strain Q1 at optimized conditions. During sequential process, complete chemical oxigen demand reduction of oil containing wastewater and theoretical volumetric yield of biodiesel was achieved. Gas chromatography/mass spectrometry chromatogram revealed that the total fatty acid methyl ester content of the produced biodiesel was >98% which is in accordance with the biodiesel quality standards specified by both ASTM and EU-14103.