This presentation discusses the bio-scouring process. Bio-scouring uses enzymes like pectinase, lipase and protease to selectively remove non-cellulosic impurities like pectin and waxes from cotton fibers. The mechanism involves pectinase hydrolyzing pectin to render waxes extractable. Key process parameters include pH, temperature, wetting agents and emulsifiers. An example recipe uses pectinase, a sequestering agent and wetting agent in water at 60°C for 30 minutes. Bio-scouring offers advantages like lower energy use and costs compared to conventional scouring while removing impurities and improving the cotton surface for dyeing. However,
4. Introduction
Bioscouring is a process by which alkaline stable pectinase is
used to remove pectin and waxes selectively from the cotton
fibre.
Pectinase, as the name suggests, hydrolyses pectins present in
cotton as a non-cellulosic impurity.
5. Types of enzymes that are used for bio-
scouring process:
Pectinase:-Pectinases are used for the removal pectic substances from
cotton.
Lipases :- They are used for the removal of natural fatty substances from
cotton
proteases:- proteases are enzymes that catalyse the hydrolysis of proteins.
6. Mechanism of bio-scouring:
The following two stages mechanisms are involved in bio-scouring
Stage :1
Removal of wax ( a major part being fatty acids, alcohols and esters) is
the critical factor for improved wettability . Pectin functions as a ‘glue’
binding wax to the fiber . Pectin removal does not by itself result in
wax removal or improved wettability but it renders wax extractable or
emulsify able.
Presence of Ca++ slows down the removal pectin and fatty acid, so a
sequestrate should, if compatible, be applied with the enzyme –
otherwise after the enzyme reaction.
7. Stage 2:
2/3 or more of the pectin must be dissolved in order to be able
to emulsify enough wax for a good wettability for dyeing.
Emulsification is strongly enhanced at temperatures above the
wax melting point, i.e. >70°C
11. Advantages of Bio-scouring:
Save energy
Save cost
Water saving
Temperature saving
Time saving
Smoother surface profile(Fully retain cellulose structure)
Lesser weight loss
Lesser costs of auxiliaries
Mild application condition
Environmental benefits
Reduces effluent treatment process/ ETP cost
12. Disadvantage of bio-scouring:
Inability of removing of cotton fiber waxes.
Enzyme activity can, however, be reduced or even completely destroyed
(denatured) by high temperatures, extremes of pH and high concentrations of
electrolytes that destroy their three-dimensional structures. Heavy metal ions
and oxidizing and reducing agents also deactivate the enzymes.
The degree of whiteness is often less and the process is not suitable for
removing seed-coat fragments and mote adequately.