Bio diesel production from distillery waste water by oleaginous yeasts by enhancing lipid production using biochemical techniques

Abstract

This study was carried out to evaluate the production of biodiesel from oleaginous yeast grown in distillery spent wash. The whole study was carried out in the laboratory and was initiated with the characterization of distillery spent wash collected at anaerobic reactor. The growth study using subcultures of M.pulcherrima was carried out with native DSW operated in batch mode. Effects of parameters like C/N ratio and temperature were identified as major influencer of biomass and lipid accumulation. From the biomass obtained, lipids were extracted using Hara and Radin methods. Initial studies were performed on DSW yielded biomass of 3.52 g/l, due to low C/N ratio of 10.4 of the native DSW. To increase C/N ratio, Different Techniques such as acid, base, and lime, algal and dark fermentation pre-treatments were performed. From the pre-treatments given above, dark fermentation was found to yield the highest C/N ratio of 36. Consequently culturing of yeast in DSW from dark fermentation, gave higher biomass of 7.048 g/l than native DSW. The effects of nutrients were observed in order to further increase the biomass and lipid yield from M.pulcherrima. Various nutrients such as phosphates, sulphates and nitrogen were selected for their effect on growth of biomass and lipid accumulation. Overall, the study was able to conclude that Alkali phosphates (Na, K) had a major influence on the lipid yield and that Transitional salt sulphates (Mn, Mg, Zn) were influential in trace amounts newline