Application of enzymes for dehairing of skins: cleaner leather processing

Abstract

Dehairing is one of the important operations in leather processing where hair is removed by using suitable chemicals. Conventional dehairing is based on application of huge amount of chemicals such as lime and sodium sulfide that generate lot of pollution problem. Enzyme assisted dehairing is the eco-friendly option that reduces nearly 40% of BOD and 50% of COD in leather processing. For this; an alkaline protease producing strains namely Bacillus subtilis was isolated from fresh goat skins and the enzyme was extracted. The enzyme was applied on flesh side goat skins at different concentration (1–4% with 10% water) and dehairing was carried out. The complete dehairing was achieved at 2% enzyme for duration of 16 h. The pollution loads such as BOD, COD, TSS, and TDS were reduced at the level of 62.8, 79.0, 88.2, and 82.5% in comparison with the control sample. The enzymatic dehaired leather was analyzed by scanning electron microscopic (SEM) studies. The SEM analyses revealed similar fiber orientation and compactness compared with control sample. The color measurements of the enzyme dehaired leather showed better color properties than control sample.