Abstract
An alkaline lipase producing bacteria was isolated from soil and identified as Serratia liquefaciens AL-11. from the results of analysis of its morphological, biochemical and physiological properties. This strain showed the highest productivity of alkaline lipase when grown at pH 9.0 and 30$\circ$C for 42 hours in the medium of 1% peptone, 0.5% tryptone, 0.9% yeast extract, 1% starch, 1% tween 80, 0.05% CaCl$_{2}$ and 0.05% NaCl. The enzyme was purified by ammonium sulfate treatment, Sephadex G-100 gel filtration and DEAE-Sephadex A-50 column chromatography. The specific activity of the purified enzyme was 27 unit/mg protein and the yield of enzyme activity was 61.3%. The homogeneity of the purified enzyme was verified by polyacrylamide gel disc electrophoresis. Molecular weight of the purified enzyme was estimated about 53,000 by sodium dodecyl sulfate- polyacrylamide gel electrophoresis. This enzyme is composed of 17 amino acids of which glycine, proline and glutamic acid were three miajor acids.
