Production of lipase by Bacillus altitudinis isolated from tannery effluent

Abstract

Lipases are important enzymes involved in hydrolytic processes that bring about the breakdown of triacylglycerol to free fatty acids and glycerol. Microbial lipases have diverse applications in the various biotechnological fields such as tannery, food, detergent and pharmaceutical industries. The main purpose of this study was to isolate and characterize the lipase-producing bacteria from the effluent of a tannery located in Kasur, Pakistan. Eight bacterial strains L1, L3, L5, L6, L9, L10, L11, and L12 were isolated, followed by screening on Tributyrin Agar Medium supplemented with mustard oil. These strains were morphologically and biochemically characterized. Growth kinetic studies of these bacteria showed optimum growth at 37°C and pH 7. Sucrose, yeast extract, and olive oil were found best as carbon, nitrogen, and oil source, respectively. The bacterial strains were non- halophilic as they preferred to grow at a low salt concentration (3%). Both of the strains L5 and L10 showed good lipase activity (99 and 92U/mL) and lipase enzyme of these strains was thermostable till 67ºC with a high protein content of 321.32 and 307.02 mg/mL, respectively. The molecular weight of lipase produced by L5 and L10 varied from 32-52kDa. Among the isolated bacterial strains, two strains L5 and L10 showed high lipase activity. 16S rRNA sequencing revealed that L5 and L10 strains had 99% homology with Bacillus altitudinis. This study signifies that the tanneries can be a good source of lipase-producing bacteria and Bacillus altitudinis can be a good lipase producer.