Valorization of fish visceral waste for proteases production and their application in destaining

Abstract

Fish processing operations generate large amount of waste in the form of viscera which accounts for nearly 5-8 per cent of the total weight of fish. Fish visceral waste is usually discarded which create environmental pollution. It is considered as a good source of enzymes including proteases. In the same line, crude proteases were extracted from species belonging to three different habitats namely; catla , little tuna and tilapia . The proteases were further evaluated for their proteolytic activity and partially purified using various precipitation techniques . Higher specific activity of 18.19 U/mg was observed in little tuna proteases. Recovery was higher in acetone precipitated catla proteases among the three different fish species. Based on higher proteolytic activity, crude proteases from little tuna were further selected for their application in destaining of blood stains. It was observed that, tuna crude protease extract effectively removed blood stains of fish blood and chicken blood in the period of 20 minutes and the he-goat blood stains were effectively removed within 10 minutes without usage of detergent. Sheep blood stain was effectively removed within 15 minutes and she-goat stain was effectively removed in 10 minutes treatment time with crude enzyme extract. The rate of stain removal was found to be higher for crude protease extracts without further purification and could be used as a destaining agent in detergent applications.