Enzymes for Leather
Enzymes for Leather
Hides and skins contain proteins and fat in between collagen
fibres and before tanning; these substances should be partially and fully
removed.
The proteins can be removed by proteases and lipases as well as
other chemicals can remove the fat.
Bating
To make leather pliable, the hides and skins require an
enzymatic treatment before tanning know as bating.
During bating, scud is loosened and other unwanted proteins are
removed. Bating de-swells swollen pelts and prepares leather for tanning. It
makes the grain surface of the finished leather clean, smooth and fine. Bating
with enzymes is an indispensable operation of leather processing to obtain best
quality of leather and cannot be substituted with a chemical process.
Traditional methods for bating employed manure of dog, pigeon or
hen. These were very unpleasant, unreliable and slow methods. Bio-technical
developments in science have now completely replaced these methods with use of
industrial enzymes.
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Protease for bating in alkaline pH conditions
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Palkocid
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Protease for bating in acidic pH conditions
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Soaking
Soaking
is done by a combination of lipase and protease to refresh the leather, once
received it is the first important operation of leather processing. Hides and
skins received into a tannery are in the four conditions, Green or fresh,
wet
salted, dry salted or as dried.
Soaking
cleans hides and skins by removing dirt, blood, flesh, grease, dung etc. and
most importantly, re-hydrates them to bring skins as far as possible back to
state of green hides.
Soaking
can agents fall into three categories, Chemical Agents, Surface-active agents
and enzymatic agents.
Enzymatic
agents are biocatalyst. Specific protease and lipase enzymes enhance water
uptake by dissolving intrafibrillary proteins that cement fibres together and
disperse fats and oils together with dirt and other contaminants present on
skin.
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A mixture of protease and lipase for soaking in alkaline pH
conditions
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Palkosoak ACP
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A mixture of protease and lipase for soaking in acidic pH
conditions
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De hairing (Un-hairing)
The conventional and most wide spread way to remove hair from
bovine hides is to use lime and sodium sulphide in a hair-burning process. They
dissolve the hair and open up the fibre structure.
Most importantly, enzyme-assisted un-hairing results in a
cleaner grain surface and improved area yield and softness. The use of a
specific protease also offers tanneries a number of options. For instance, the
sulphide and lime requirements can be reduced by as much as 40% while
maintaining the same liming time. Alternatively tanners can shorten the liming
time by at least half without any loss of quality.
The hair-burning process is the most widespread but a better
alternative to this, is the hair-saving process, which is environment friendly,
where the hair is not dissolved but can be filtered out from the liming float.
It is possible to reduce the COD up to 50% and BOD up to 30% in waste
discharges.
Industrial
biotech offers specific protease for
un-hairing which can be used either alone or in combination lime and sodium
sulphide
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Palkodehair
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Protease for un-hairing in high alkaline pH conditions
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