A Viable Approach for Utilization of the Agro-Industrial Waste in Biodiesel Industry: Using Deoiled Jatropha curcas Seed Meal to Produce Protease by Aspergillus niger under Solid-State Fermentation

Deoiled Jatropha curcas seed meal (DJSM), a chief waste material of oil extraction industry, will be generated on a large scale due to the growing interest in using Jatropha curcas seed oil as a feedstock for the production of biodiesel. Up to now, there is very little work on viable approach for the use of DJSM to the best of our knowledge. This article reports our studies on the utilization of this huge biomass by solid-state fermentation (SSF) for the production of protease. Aspergillus niger was purchased and used for fermentation. The optimal fermentation conditions and the protease properties were studied. Maximum protease production (9204U/g of dry substrate, U/g) was obtained at 50% of substrate moisture, a growth period of 4 days, supplementation with 5% (wt) of glucose. The results of protease characterization showed that the optimal temperature and pH were 50°C and 4.0, respectively. The Vmax and Km of the protease from Aspergillus niger were 0.0028 μmol (s mg)^-1 protein and 0.1854 mM, respectively. Organic solvent can enhance enzyme activity. In comparison with control, the activities were increased by 31.21% and 24.11% when the protease was solved by 15% (v/v) of methanol and 10% (v/v) of ethanol, respectively.