and temperatures, be able to withstand oxidizing and chelating agents and be
effective at low enzyme levels in detergent solutions. The leading enzyme suppliers
and detergent manufacturers are actively pursuing the development of new enzyme
activities that address consumer needs for improved cleaning, fabric care and
antimicrobial properties [31]. As the detergent industry grow both in terms of size
and complexity cleaning properties, new applications and demand of the enzyme
will continue to expand.
Use of enzyme in processing of hide and skin has been practiced since ancient
times. Traditionally, biocatalysts found in dog’s dung were used to soak hides and
skins to make them pliable by extracting protein, oil and fat constituents. Use of this
method was not only unhygienic but unsustainable due to high market demand and
health concern. The reasoning behind use of proteolytic enzyme from dog’s dung
lies in the fact that the protein is the major constituent of hair found on skins and
hides. Hair is composed of α-keratin fibres and insoluble protein molecules
containing a large fraction of cysteine residues and having α-helix conformation.
The α-keratin is arranged in piles of fibrils. Different skin layers are composed of
collagens, α-keratin and some elastin. Proteases can hydrolyse the protein fraction of
dermatan sulphate, making the collagen more reachable by water and reducing the
attachment of the basal layer [32]. Extremophiles can survive under extreme conditions. These include temperature (À2 to 12
C, 60 to 110
C), high pressure, radiation, salinity (2–5 M NaCl) and pH (<2, >9) [33]. Alkaline lipases from Bacillus
strains, which grow under highly alkaline conditions in combination with other
alkaline or neutral proteases, are currently being utilized in leather industry for
assisted dehairing of animal hides and skin [33].
5 Enzymes from Extremophiles Microorganisms
The demand for industrial enzymes that can withstand harsh operating conditions
such as high pH, temperature, salinity and pressure has greatly increased over the
past decade. This has led to extensive research in exploring extremophilic microorganisms in search for novel enzymes. As a result enzymes from thermophiles and
alkaliphiles have become the subject of special interest for biotechnological applications due to their efficiency and high stability at adverse operational and/or storage
conditions [34]. This is because enzymes obtained from alkaliphiles are stable when
added to detergents due to their inherent tolerance to high pH and can also generally
function in the presence of bleaching chemicals [35]. Extreme environmental conditions require optimized interactions within the protein, at the protein–solvent
boundary or with the influence of extrinsic factors such as metabolites, cofactors
and compatible solutes [36]. Factors that contribute to the remarkable stability of
extremozymes include an increased number of ion pairs, reduction in the size of
loops and in the number of cavities, reduced ratio of surface area to volume, changes
in specific amino acid residues, increased hydrophobic interaction at subunit
204
W. C. Wanyonyi and F. J. Mulaa
effective at low enzyme levels in detergent solutions. The leading enzyme suppliers
and detergent manufacturers are actively pursuing the development of new enzyme
activities that address consumer needs for improved cleaning, fabric care and
antimicrobial properties [31]. As the detergent industry grow both in terms of size
and complexity cleaning properties, new applications and demand of the enzyme
will continue to expand.
Use of enzyme in processing of hide and skin has been practiced since ancient
times. Traditionally, biocatalysts found in dog’s dung were used to soak hides and
skins to make them pliable by extracting protein, oil and fat constituents. Use of this
method was not only unhygienic but unsustainable due to high market demand and
health concern. The reasoning behind use of proteolytic enzyme from dog’s dung
lies in the fact that the protein is the major constituent of hair found on skins and
hides. Hair is composed of α-keratin fibres and insoluble protein molecules
containing a large fraction of cysteine residues and having α-helix conformation.
The α-keratin is arranged in piles of fibrils. Different skin layers are composed of
collagens, α-keratin and some elastin. Proteases can hydrolyse the protein fraction of
dermatan sulphate, making the collagen more reachable by water and reducing the
attachment of the basal layer [32]. Extremophiles can survive under extreme conditions. These include temperature (À2 to 12
C, 60 to 110
C), high pressure, radiation, salinity (2–5 M NaCl) and pH (<2, >9) [33]. Alkaline lipases from Bacillus
strains, which grow under highly alkaline conditions in combination with other
alkaline or neutral proteases, are currently being utilized in leather industry for
assisted dehairing of animal hides and skin [33].
5 Enzymes from Extremophiles Microorganisms
The demand for industrial enzymes that can withstand harsh operating conditions
such as high pH, temperature, salinity and pressure has greatly increased over the
past decade. This has led to extensive research in exploring extremophilic microorganisms in search for novel enzymes. As a result enzymes from thermophiles and
alkaliphiles have become the subject of special interest for biotechnological applications due to their efficiency and high stability at adverse operational and/or storage
conditions [34]. This is because enzymes obtained from alkaliphiles are stable when
added to detergents due to their inherent tolerance to high pH and can also generally
function in the presence of bleaching chemicals [35]. Extreme environmental conditions require optimized interactions within the protein, at the protein–solvent
boundary or with the influence of extrinsic factors such as metabolites, cofactors
and compatible solutes [36]. Factors that contribute to the remarkable stability of
extremozymes include an increased number of ion pairs, reduction in the size of
loops and in the number of cavities, reduced ratio of surface area to volume, changes
in specific amino acid residues, increased hydrophobic interaction at subunit
204
W. C. Wanyonyi and F. J. Mulaa