In the present study, Aspergillus costaricaensis CBS115574 which was previously isolated from the non-leguminous field soil collected from the Kishangarh city of state Rajasthan confirmed by 16S rRNA gene/ITS/D1-D2 region sequencing. The cultural parameters (Carbon sources, nitrogen sources, moisture content, pH, temperature and particle size etc) of solid-state fermentation have been optimized for the improved extracellular lipase production. Among different carbon sources, A. costaricaensis showed best lipase activity (253.6 IU/g/min) in the presence of lactose. Among the various concentration (0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4% and 1.6%) of lactose, the optimum concentration was found to be 1.6%. Among different nitrogen sources, highest lipase activity (55.32 IU/g/min) was obtained in the presence of yeast extract and the optimum concentration of yeast extract was found to be 0.5% for maximum lipase activity (236.69 IU/g). Further the best lipase activity was obtained in the medium of pH 8.0 (312.330 IU/g/min) at 28ºC after 48 hrs of incubation period. Further the particle size of solid substrate was optimized and highest lipase activity was found when fine particle size was used. Among the various ratio of moisture content, highest lipase activity (317.09 IU/g/min) was found at 1:6 moisture content. From the present work, it is figure out that for the enhanced production of lipases the medium parameters required to be optimized. The above results help out the authors in carry out the further studies of purification and characterization of lipase enzyme produced from A. costaricaensis CBS115574.

In the present study, the lipase of alkaline nature obtained from the previously isolated strain Aspergillus costaricaensis CBS115574 was characterized and purified out using ammonium sulfate precipitation and chromatographic techniques on Diethylaminoethyl A-50 and Sephadex G-100. The purified lipase has the molecular weight of ~50 kDa which was determined by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Zymography by using the phenol red along with the purification fold of 6.63 and specific activity of 31.73 IU/mg after the gel filtration chromatography. Lipase was found to be stabilized at the pH 7 (122.68 IU/g/min) and at the temperature of 80ºC (141.36 IU/g/min) with its optimal activity at pH 8 and temperature 50ºC. The Km and Vmax value for extracellular lipase were reported to be 29.62 mM and 74.07 IU/ml with their higher tolerance to glycerol (organic solvent), tween 80 (detergent), Ethylene diamine tetra acetic acid (activator & inhibitor), hydrogen peroxide (oxidizing & reducing agent) and sodium chloride (metal ions) with lipase activity of 106.74 IU/g/min, 84.53 IU/g/min, 108.06 IU/g/min, 97.17 IU/g/min and 118.7 IU/g/min. The above results suggested that A. costaricaensis CBS115574 lipase found a suitable position for application in different types of industries.