Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

BENCH SCALE BATCH FERMENTATION STUDIES WITH NOVEL BACTERIAL SOIL ISOLATES FOR LIPASE PRODUCTION

BHAVANI MANDEPUDI, DAVID MANDEPUDI AND VENKAIAH CHOWDARY GHANTA

Abstract

A bench scale batch fermentation study was carried out using the newly isolated lipase producing bacterial strains, Aneurinibacillus migulanus sp. SPSU B4, Pseudomonas sp. SPSU B3, and its mutant strain Pseudomonas sp. SPSU B3UVS30 using their respective optimal nutrient broth media containing emulsified oil and nitrogen sources. The fermentation process parameters were set as 30oC, 450 rpm, pH 8.0 for 24hr fermentation process. Broth samples (10mL) were withdrawn at an internal of 1hr from the respective broths separately and analyzed them for biomass produced and lipase activity, while the corresponding DO measurements were recorded from the control panel. In the results it was found that the fermentation of olive oil emulsified in the nutrient broth by Aneurinibacillu migulanus sp. SPSU B4, was of high metabolic rate producing the maximum growth associated lipase activity of 45U with its maximum growth of 3.9mg/mL by 12-14hrs of fermentation period. Similarly Pseudomonas sp. SPSU B3 produced the non-growth associated lipase to a maximum activity of 20U by selective and sequential consumption of available carbon sources (substrates) in the broth media, producing diauxic growth profile. On the other hand the mutant strain Pseudomonas sp. SPSU B3UVS30 produced the maximum biomass of 8.3mg/mL by 12hrs of fermentation period by simultaneous consumption of available substrates and produced mixed growth associated lipase to the extent of 40U. However, the DO levels in the fermentation broth of all the three strains, was found to be the limiting nutrient factor for the microbial growth and lipase production. So these novel lipase producing isolates Aneurinibacillu migulanus sp. SPSU B4, Pseudomonas sp. SPSU B3 and its mutant Pseudomonas sp. SPSU B3UVS30 may be preserved and made available to the scientific community for further exploration of the strains for their possible use in research, academics and industry.