A novel amylase-based biocatalyst developed by researchers at the Central Leather Research Institute (CSIR-CLRI), Chennai, helps in processing leather in an environment-friendly way and also drastically cutting the time taken to process the skin at the pre-tanning stage.
Pre-tanning process generates 60-70% of total pollution during processing. This pollution is responsible for polluting water bodies and their ecosystem. The new discovery can lead to reduction in water pollution.
In the new proceess using bio-catalyst ,the quantum of effluent discharge is considerably cut as there is threefold reduction in water usage.
Chromium, that is used for increasing the stability of the collagen through cross-linking is less utilised. Since no chemicals are used, the chemical oxygen demand drops by about 35% while the total solid effluent load reduces by over 50%.
The reason why less chromium and water are required at the pre-tanning stage when the biocatalyst is used is primarily because of the 120-fold higher binding of the biocatalyst to the glycan sugar present predominantly in the skin.
Once the catalysts binds to the sugar, it selectively breaks down (hydrolysis) the sugar thus opening up the skin fibre without much effort.
Traditionally, enzymes take three-to-four hours to open the fibres. If lime and sulphate are used it takes 12 hours to complete the process. Using Bio-catalyst reduces the time required to 10 minutes.
Importance of Biocatalyst discovery
The biocatalyst also penetrates deep into the skin unlike the traditionally used enzymes. Deep penetration of the biocatalyst ensures less amount of chromium to be used to increase the stability of the collagen and the quality of the finished leather also becomes superior.
About 21% of the chromium used gets absorbed by the skin, which is far more than when other enzymes or chemical-based methods are used, leading to reduced chromium in the effluent discharge.
The biocatalyst is stable even at a high temperature of 90 degree C and pH 10 and so up to 95% of the enzyme can be recovered after a single process and reused.
Biocatalysis refers to the use of living systems or their parts to speed up chemical reactions. In biocatalytic processes, natural catalysts, such as enzymes, perform chemical transformations on organic compounds.