could be the most effective way in reducing the use of toxic chemicals for soaking,
dehairing and bating. The bio-based leather processing aims at use of enzymes
instead of chemicals, thereby consuming much less energy, chemicals and water.
It can significantly contribute to both economic development and cutting down
environmental pollution.
Enzymes are biocatalysts that are suitable for the practice of green chemistry and
can be utilized to achieve eco-friendly industrial processing. Enzymes have been
utilized broadly in manufacturing of household products. Amongst the largest groups
of industrial enzymes, viz. proteases, amylases and lipases, proteases account for
about 59–65% of the total worldwide enzyme sale [13, 14]. Alkaline active proteases
have been used in products such as cosmetics, synthesis of oligopeptides, drugs,
detergents, fertilizers, cloth and in processing food and leather [15–19]. Keratinolytic
protease is one of the marvellous biocatalysts able to hydrolyse and break disulphide
bonds found in hair with little damage to skin/hide grain [7].
Enzymatic leather processing is a transformative and ambitious technology which
simultaneously addresses major economic, social and environmental challenges
affecting the tannery. The ‘greening’ of the leather processing industry, with the
elimination of toxic chemicals has the potential to revive collapsed leather industries
severely restricted by pollution and health concerns. Use of enzymes may drastically
reduce the pollution load of the effluents, help in hair recovery and at the same time
enable recycling (such as wastewater) since there is no cross contamination by toxic
chemicals. Enzymes are not persistent and can be readily deactivated and
biodegraded. One of the major hindrances to the uptake of enzyme technology for
the leather industry just like most industries is the technical limitations around
tailoring an enzymatic process to the already existing standardized industrial chemical processes. However, with the advent of technology, it has been possible to
design an enzymatic process that easily fits into the already existing factory operational parameters. Successful research has been carried out in processing of cow-,
goat-, sheep- and fishskins using proteases, though their use has not been fully
exploited due to the following technical limitations.
1. Limited number of people with product knowledge on enzyme production,
application and specificity.
2. High initial cost of equipment for enzyme production.
3. Enzymes are limited in the activity range especially with regard to pH and
temperature. This requires application of more than one enzyme for complete
processing.
4. If not well controlled, one can risk destroying the valuable grain surface.
4 Protease
Protease (peptidases or proteolytic enzymes) constitutes a large group of enzymes that
conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide
bonds that link amino acids together in the polypeptide chain forming the protein
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W. C. Wanyonyi and F. J. Mulaa
dehairing and bating. The bio-based leather processing aims at use of enzymes
instead of chemicals, thereby consuming much less energy, chemicals and water.
It can significantly contribute to both economic development and cutting down
environmental pollution.
Enzymes are biocatalysts that are suitable for the practice of green chemistry and
can be utilized to achieve eco-friendly industrial processing. Enzymes have been
utilized broadly in manufacturing of household products. Amongst the largest groups
of industrial enzymes, viz. proteases, amylases and lipases, proteases account for
about 59–65% of the total worldwide enzyme sale [13, 14]. Alkaline active proteases
have been used in products such as cosmetics, synthesis of oligopeptides, drugs,
detergents, fertilizers, cloth and in processing food and leather [15–19]. Keratinolytic
protease is one of the marvellous biocatalysts able to hydrolyse and break disulphide
bonds found in hair with little damage to skin/hide grain [7].
Enzymatic leather processing is a transformative and ambitious technology which
simultaneously addresses major economic, social and environmental challenges
affecting the tannery. The ‘greening’ of the leather processing industry, with the
elimination of toxic chemicals has the potential to revive collapsed leather industries
severely restricted by pollution and health concerns. Use of enzymes may drastically
reduce the pollution load of the effluents, help in hair recovery and at the same time
enable recycling (such as wastewater) since there is no cross contamination by toxic
chemicals. Enzymes are not persistent and can be readily deactivated and
biodegraded. One of the major hindrances to the uptake of enzyme technology for
the leather industry just like most industries is the technical limitations around
tailoring an enzymatic process to the already existing standardized industrial chemical processes. However, with the advent of technology, it has been possible to
design an enzymatic process that easily fits into the already existing factory operational parameters. Successful research has been carried out in processing of cow-,
goat-, sheep- and fishskins using proteases, though their use has not been fully
exploited due to the following technical limitations.
1. Limited number of people with product knowledge on enzyme production,
application and specificity.
2. High initial cost of equipment for enzyme production.
3. Enzymes are limited in the activity range especially with regard to pH and
temperature. This requires application of more than one enzyme for complete
processing.
4. If not well controlled, one can risk destroying the valuable grain surface.
4 Protease
Protease (peptidases or proteolytic enzymes) constitutes a large group of enzymes that
conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide
bonds that link amino acids together in the polypeptide chain forming the protein
202
W. C. Wanyonyi and F. J. Mulaa