Isolation and screening of transesterifiable lipid accumulating bacteria from dairy sludge for biodiesel production

Abstract

Rapid depletion of fossil fuel sources is the main reason for onset of alternative fuel. Recently, microbial oils, also known as single cell oil, are attracting more attention over vegetable oils for biodiesel production as they are easy to produce with higher yield and do not involve in foodfuel competition. In this paper, we envisage the lipid production from oleaginous bacteria isolated from dairy sludge. Sludge samples were collected from Omfed dairy, Rourkela, Odisha. Isolation of bacteria was carried out by using sludge extract medium. Eight morphologically different bacteria were isolated from the dairy sludge. The bacterial isolates that showed maximum lipid content were selected for further study. Further, experiments were carried out to observe the effect of inoculum size and medium composition on dairy wastewater on the lipid production. The selected bacterial isolates were also analysed by 1 H nuclear magnetic resonance (NMR) spectroscopy. The results showed that content of saturated fatty acids was higher than unsaturated fatty acids. Gas chromatography analysis showed that transesterified bacterial lipids were well suited for biodiesel.