Production, properties and applications of proteases from pongamia oil seed cakes

De-oiled cakes (meal) containing proteins and carbohydrates are inevitably produced during extraction of oil from seeds. These cakes are inexpensive, sustainable and renewable sources but have limited applications. In this present study, de-oiled pongamia seed cake was used as substrate to produce protease by Bacillus licheniformis, Acinetobacter pittii, and Aspergillus niger under different culture conditions such as pH and temperature. Furthermore, the influence of diverse carbon and nitrogen sources on enzyme production was studied. Under the optimized conditions but without any additional inducers, the activity of protease produced by Aspergillus niger was 27.5 UmL(-1), which is 34% higher than the activity obtained using B. licheniformis and about 6.7 times higher compared to that obtained using A. pittii. Addition of nitrogen or carbon source leads to an increase in enzyme activity of up to 240% with urea by Aspergillus niger and 163% with fructose by Acinetobacter pittii. Proteases obtained had optimum production at pH 8 and temperature of 30 and 40 degrees C. The enzyme produced was effective in hydrolysing the gelatin layer from used x-ray films, enabling the film to be recycled and was also able to coagulate milk, suggesting that it may be suitable for food applications.