Valorization of seafood waste management

Introduction

Seafood is a major source of nutrition. We eat the edible part and discard the hard part of the crabs, shrimps, prawns, etc. Therefore, the seafood industry yearly generates more approximately 106M tons of waste which often contains high value product that are not utilized due to the inadequate management. If this wastes not maintain properly then it can create environmental issues. These wastes are rich in chitin, it is a biocompatible and biodegradable polysaccharide. One of the most effective ways to convert chitin into chitosan by the enzymatic deacetylation process, especially using the compound chitin deacetylase (CDA) in the relatively green way.

chitosan has biocompatible properties use in pharmaceutical industry, food biomedical, cosmetics, textile industry.

‘Chitin to chitosan :- Waste to value’

Chitin is a polysaccharide found in outer shell of crabs. It is the second most abundant biopolymer in nature .Chitosan composed of 2-amino 2-deoxy D-glucopyranose units joined together by β(1-4) glycosidic bond .chitosan has hydrophilicity and amino groups which is positively charged in acidic conditions. The conversion of chitosan from chitin can occur through the following processes:

1. Chemical Deproteinization- Breaks the bond between protein and chitin using strong chemicals and high temperature.

2. Demineralization- Minerals like calcium carbonate are removed from materials. The following reaction can be seen here:

2HCl+CaCO3–> CaCl2+ H2O+ CO2

3. Enzymatic Deacetylation- Chitin deacetylase removes acetyl group to convert chitin into chitosan. This approach is more environmentally friendly as an alternative, to using chemical method. This process consists under mild condition such as natural PH(extracellular 7-12) and temperature(50-60°C) which avoids damage to the polymer. Chemical method is quicker and more viable by a longer scale but produce less pure chitosan and harm the environment. When purity, central and environmental concerns are targeted, chitin deacetylase has often been used.

Role of chitin deacetylase

Chitin deacetylase catalyses the hydrolysis of acetyl group from chitin, being converted into chitosan.

Till now, chitin deacetylase has been isolated from several fungi including A.coerulea, C.lindemuthianum, etc.

Chitin deacetylase enhances the enzyme activity in the presence of Zn2+, Ca2+, Co2+ . EDTA could eliminate chitin deacetylase’s activity.

Chitosan: Unlocking the sustainable weapon

Chitosan has some important uses as nanoparticles, for increasing the effectiveness of agrochemicals. It’s also useful in tissue engineering for regeneration of lost tissues. It can be used as a food preservative.

Scope of seafood waste

Indian seafood industries generate millions of tons of waste each year (fish waste- 302750 tons). Maximum waste is generated from several states like Gujarat (30.51%), Maharashtra (23%), Kerala (17.5%). Many other countries like Norway, Japan and Canada have innovated new processes and transformed waste into valuable resources.

Conclusion

Nowadays waste management is a troublesome issue. It can grow environmental concerns and requires attention from seafood industry and government. Chitin deacetylase plays an important role in transforming chitin to chitosan. Seafood waste impacts both environment as well as economy. It is a crucial step to save marine ecosystem and ensuring long term industry viability.

Arghyadeep Bisoi

University/College name : Utkal University Biotechnology department