About 1,234,332 tons of marine food is consumed on a weekly basis all around the world leading to the production of marine food processing waste like fish scales, crab and prawn shells, fins bones etc. In the present study crab and prawn shells were collected from a local fish market powdered and used as a substrate for Aspergillus niger and the activity of protease and amylase were analysed after three days. Two mutated strains of A. niger, were also used apart from the wild type A. niger strain.