Background:
Groundnut is an important oilseed crop of India. The cake that is left after expulsion of oil from kernels is the major by-product of groundnut oil industry. Expeller cakes generally contain about 6 10% oil. This residual oil is extracted through solvent, which further enriches the cake in protein. This de-oiled cake contains about 50% protein and 12.5% starch. Both oil and de-oiled groundnut cakes are, however, unfit for human consumption as some amount of shell is mixed with kernels as a crushing aid. Usually, these cakes are exported and used as animal feeds. De-oiled groundnut cakes being rich in protein and starch, can be used as substrates for production of proteases by employing proteolytic microorganisms. Currently, India produces around 2.0 million tonnes of groundnut cakes, which are being used mainly as animal feed. Export of these cakes has reduced considerably due to aflatoxin contamination. Thus, groundnut cakes are presently being used for much less economic purposes than its actual potential. This hidden potential of groundnut cakes can be exploited by developing economically viable technologies for the production of proteases (acid, neutral and alkaline) at industrial scale by microbial fermentation. Proteolytic enzymes account for nearly 60% of the market for industrial enzymes in the world. They find application in a number of industrial processes like food processing and pharmaceuticals, leather, detergent, baking, textile and brewing, animal feed and bio-treatment of organic wastes, etc:
Technology details:
A simple process knowhow has been developed for producing proteases from de-oiled groundnut cake by employing industrially useful microbes like Aspergillus nidulans, and Bacillus subtilis by solid substrate and/or liquid fermentation. By employing solid substrate fermentation with Aspergillus nidulans upto 18-25 IU of neutral proteases/g of cake can be obtained after 72 h of fermentation. In liquid fermentation, the protease production potential can be improved to 200-250 units/g deoiled cakes. This neutral protease produced by Aspergillus nidulans is tolerant to detergents available in the market. By employing Bacillus sp. P5, all the three proteases (80, 160 and 350 IU/mg protein for acid, neutral and alkaline proteases) can be produced in slurry fermentation. In liquid fermentation, the production potential of proteases can be improved to upto 500 IU/g deoiled cakes employing Bacillus sp. P5. Besides, proteases produced by Bacillus sp. P5 are tolerant to salinity; high temperature, detergent and heavy metals. Considering the potential, processing of 100 kg of de-oiled groundnut cakes can produce upto 50.0 million IU of proteases by employing microbes. At present market price, from processing of 100 kg of de-oiled groundnut cake an amount of Rs. 30000-35,000/ can be earned as net income. The proteases produced has wide applications in Silk degumming, Leather bating, Leather dehairing, Protein hydrolysis, Detergent, Baking and milling, Biscuit baking, Animal feed, Dry cleaning, Tenderizing meat, digestive enzymes, etc:
Unique features of the enzyme proteases produced by this technology:
• ~500 IU of proteases/ g de-oiled cakes in liquid fermentation:
• Compatible with detergent:
• Tolerant to high temperature (50-55oC):
• Compatible with salty water:
• Tolerant to heavy metals: