Partial Purification, Characterization and Biodiesel Application of Streptomyces lienomycini Lipase

The lipase from Streptomyces lienomycini 350-2 (LipS350-2) was partially purified, characterized, and its transesterification capacity was determined. Lipase activity was measured using p-nitrophenylpalmitate (p-NPP) as a substrate. LipS350-2 was partially purified using ammonium sulfate precipitation, dialysis and gel filtration chromatography. The lipase was found to have a specific activity of 1466.8 U/mg and a molecular mass of approximately 52 kDa. Optimal pH and temperature for LipS350-2 was 9.0 and 40 degrees C, respectively. The lipase exhibited good stability at pHs from 7-11 and at temperatures ranging from 4 degrees C-40 degrees C. The enzyme conserved approximately 69% of its activity at the end of 1 h in the presence of isopropanol. Hydrolytic activity of the enzyme was highest towards p-NPP (C-16) among the various p-nitrophenol esters tested and towards waste edible oil among the natural substrates tested. With regard to storage stability, LipS350-2 enzyme can be stored at +4 degrees C for 30 days. Biodiesel was then produced using the lipase as a catalyst, and the fatty acid alkyl ester content of the biodiesel product was analyzed. The measurements of transesterification indicated LipS350-2 to be a potential catalyst for biodiesel production due to its high activity under thermophilic conditions and stability in the presence of various alcohols.