Improved lipase biosynthesis by a newly isolated Penicillium sp. grown on agricultural wastes

Abstract

The main objective of this work was the optimization of the lipase production by a newly isolated Penicillium sp. in supplemented soybean meal, considering a fixed C/N ratio (6.11). The kinetic behavior of lipase production was also evaluated, quantifying activity at different pH. The production of the enzyme was maximum using a substrate particle size between 1 and 2 mm and inoculum concentration of 2×108 spores · g-1, at 20°C. Lipase activities of about 200 U · g-1 at pH 4.0 were obtained after 120 h of cultivation, but activities at pH 7.0 as high as 317 U · g -1 could be obtained after 96 h. The activities measured at pH 9.0 were also promising, ranging from 177 to 191 U · g -1. The results obtained are relevant, since high lipase activities, in a wide range of pH (4.0 to 9.0) were obtained from a newly isolated microorganism in a low-cost fermentation medium. The variation in the C/N ratio at the previously optimized conditions showed that the best results were obtained at C/N of 6.11. © 2009, Gen Publishing Inc., Mary Ann Liebert, Inc.