and complex. While new chemical catalysts are becoming available, the unique
properties of proteolytic and lipolytic enzymes as biocatalysts offer green alternatives
such as reduced use of organic solvents, efficient use of reagents and elimination of
chemical catalysts. Enzyme technology could be the most useful technology for
adding value to by-products and solving the waste problem in the tannery industry
globally. A few reports are available on recovery of lipids by enzymatic hydrolysis of
skin and hides and subsequent enrichment of omega-3 fatty acids using lipases [54,
55]. In the case of fishskins, omega-3 fatty acids devoid of most of the saturated fatty
acids are preferred over the native fish oils since they keep the daily intake of lipids as
low as possible. Omega-3 polyunsaturated fatty acids (PUFAs) are gaining recognition as important components of the human diet. They have been implicated in
lowering the incidence of certain cardiovascular diseases, improving neural and
retinal development in infants and slowing the growth of cancerous cells. In addition,
several studies have shown fish diet containing PUFA before the period of gonad
maturity affect fecundity, fertility, hatching rate and quality of eggs [56]. Two
important PUFAs, eicosapentaenoic (20:5, n-3; EPA) and docosahexaenoic acids
(22:6, n-3; DHA), are mainly found in sheep- and goatskins and cold water fish oils
and also in substantial amounts in oil of Nile perch, a warm water fish [54]. In
addition, fishskins contain docosapentaenoic acid (DPA) that also has been reported
to be present in seal oil [54, 57]. Hence PUFA concentrates from fishskins would in
addition to DHA and EPA present in cold water fish oil also contain DPA making
them unique.
11 Bioinnovation Potential of Tannery Waste Biomass
Tannery waste is an attractive biowaste stream as it is produced in significant
quantities globally. It is therefore possible to apply a cascading approach, giving
priority to the transformation towards bioproducts while also permitting a possible
conversion to energy, e.g. to bioparaffin and biodiesel. By adopting enzyme technology for recovery of protein hydrolysate, oil from skin and hide waste, it would
therefore also be possible to recover other functional ingredients such as collagen.
Since enzymes work best at low temperatures ( 55
C), the process minimizes
oxidation of unsaturated omega-3 fatty acids and results in fish protein hydrolysate
(FPH) with higher degree of hydrolysis, and the process is more energy efficient as
compared to conventional chemical treatment and cooking methods. Soluble proteins have been used in aquaculture, in preparation of fortified animal feeds and
protein supplements. Due to its high protein content, sludge emanating from such a
process can be a source of plant nutrients for food production or as animal feed. Use
of raw tannery waste may causes problems of odour and attracting wild/domestic
animals; thus it needs to be composted prior to its use.
The by-products from tannery processing are a potential source of collagen, the
especially skin. Collagen is the main component found in skin, and gelatin can be
obtained through partial hydrolysis of collagen. Gelatin from warm water fishskins is
Alkaliphilic Enzymes and Their Application in Novel Leather Processing. . .
215
properties of proteolytic and lipolytic enzymes as biocatalysts offer green alternatives
such as reduced use of organic solvents, efficient use of reagents and elimination of
chemical catalysts. Enzyme technology could be the most useful technology for
adding value to by-products and solving the waste problem in the tannery industry
globally. A few reports are available on recovery of lipids by enzymatic hydrolysis of
skin and hides and subsequent enrichment of omega-3 fatty acids using lipases [54,
55]. In the case of fishskins, omega-3 fatty acids devoid of most of the saturated fatty
acids are preferred over the native fish oils since they keep the daily intake of lipids as
low as possible. Omega-3 polyunsaturated fatty acids (PUFAs) are gaining recognition as important components of the human diet. They have been implicated in
lowering the incidence of certain cardiovascular diseases, improving neural and
retinal development in infants and slowing the growth of cancerous cells. In addition,
several studies have shown fish diet containing PUFA before the period of gonad
maturity affect fecundity, fertility, hatching rate and quality of eggs [56]. Two
important PUFAs, eicosapentaenoic (20:5, n-3; EPA) and docosahexaenoic acids
(22:6, n-3; DHA), are mainly found in sheep- and goatskins and cold water fish oils
and also in substantial amounts in oil of Nile perch, a warm water fish [54]. In
addition, fishskins contain docosapentaenoic acid (DPA) that also has been reported
to be present in seal oil [54, 57]. Hence PUFA concentrates from fishskins would in
addition to DHA and EPA present in cold water fish oil also contain DPA making
them unique.
11 Bioinnovation Potential of Tannery Waste Biomass
Tannery waste is an attractive biowaste stream as it is produced in significant
quantities globally. It is therefore possible to apply a cascading approach, giving
priority to the transformation towards bioproducts while also permitting a possible
conversion to energy, e.g. to bioparaffin and biodiesel. By adopting enzyme technology for recovery of protein hydrolysate, oil from skin and hide waste, it would
therefore also be possible to recover other functional ingredients such as collagen.
Since enzymes work best at low temperatures ( 55
C), the process minimizes
oxidation of unsaturated omega-3 fatty acids and results in fish protein hydrolysate
(FPH) with higher degree of hydrolysis, and the process is more energy efficient as
compared to conventional chemical treatment and cooking methods. Soluble proteins have been used in aquaculture, in preparation of fortified animal feeds and
protein supplements. Due to its high protein content, sludge emanating from such a
process can be a source of plant nutrients for food production or as animal feed. Use
of raw tannery waste may causes problems of odour and attracting wild/domestic
animals; thus it needs to be composted prior to its use.
The by-products from tannery processing are a potential source of collagen, the
especially skin. Collagen is the main component found in skin, and gelatin can be
obtained through partial hydrolysis of collagen. Gelatin from warm water fishskins is
Alkaliphilic Enzymes and Their Application in Novel Leather Processing. . .
215