NCM-JANUARY 2006

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The Contamination of catalase by

chemical based reducing agent…The application of enzymes in textile processing is quite old. This is an eco friendly way of processing the fabrics.

The concept of White Chemistry which relates the use of enzymes in various processing is a happening phenom-

enon now. Texile Industry is one of the pioneer in this field. Enzymatic peroxide killer lies in oxidoreductase range

of enzyme. These enzyme break hydrogen peroxide into water & oxygen. Enzyme being a biological catalyst &

ecofriendly is little costlier as compared chemical. Biocon started as an enzyme company so its core competence

lies in enzyme manufacturing. In a recent comparison of catalase enzymes available in the market, Biocatalase

PL+ the premier enzymatic peroxide killer of Biocon was compared with other catalase enzymes it was found that

almost all other enzymes except Biocatalse PL+ were contaminated with reducing agent like Sodium Bisulphide

ranging from 10 to 20%. We have reevaluated it & then finally confirmed. If this trend continues it will be impos-

sible to achieve full prove ecofriendly process. This is fatal for our environment too it is somewhat like contaminat-

ing chilly powder with red bricks powder. We have a detail report on the catalase samples found to be contami-

nated with chemical based reducing agent. For any further enquiry the author can be contacted directly.

Idometric test for Sodium Bisulphide NaHSO3 contamination in catalase Enzyme

Steps:

1) Take 5 gms of enzyme dissolve it in 100 ML of distilled water

2) Take 20 ML of this solution

3) Prepare 50 ML of 0.1Normal Iodine solution

4) Mix 20 ML of 5% enzyme solution with 50 ML 0.1N Iodine solution

5) The mixture is shaken well & reverse titrated with 0.1 N Sodium Thiosulphide in the presence of starch

indicator to the disappearance of blue color.

The reaction is:

NaHSO3 + I2 +H2O ................................> Na HSO4 + 2HI

Iodine consumed = 50-Test reading

Let this figure be IC more the value of IC more is the Iodine consumed i.e. this iodine has reacted with Sodium

Thiosulphide.The consumption of Iodine starts as soon as the Iodine solution is mixed with diluted enzyme

solution if there is any contamination of Sodium Bisulphide in enzyme.

If there is no contamination of Sodium Bisulphide in enzyme then the IC will be zero. So more the reading of IC

more is the contamination & hence the enzyme is not pure. The enzyme that shows high IC reading has more

contamination & hence its not pure it is a mixture of enzyme based Peroxide killer & Chemical based peroxide

killer. Chemical based killer is generally Sodium Bisulphide, which is a reducing agent. When residual peroxide

is killed post bleaching by the help of killer enzyme then the contaminated one will have two factors which will kill

the peroxide one is enzyme & the other is reducing agent like Sodium Bisulphide.They may take less dose as

compared to pure enzyme based killer but they have many draw backs too as compared to pure enzyme based

peroxide killer.

Some of the advantages of using pure enzyme over contaminated one are:

1) Enzyme dissociates Hydrogen Peroxide into harmless water & oxygen as compared to thio salts in case of

chemical based killer.

2) In enzymatic killing there is no formation of thio salts hence the TDS level in the effluent is quite low as

compared to chemical based killer. (1 gpl of Thio salt can contribute TDS upto 1000 ppm)

3) There is no degradation of fibers or dyes in case of enzymes but it is in the case of contaminated killer.

4) Less rinsing required after enzyme treatment as compared after chemical treatment hence more water is

required when a chemically contaminated killer is used or the dyeing may be spoiled.

5) Adding too little contaminated killer can oxidise dyestuff or if it is dosed in large amount it can reduce

dyestuff. But by mistake if more enzymatic killer is dosed there is no harm.

Any way the contaminated killer is harmful as compared to pure enzyme based. Small petty gains are of no value

as compared to making the process eco-friendly. All chemical companies should strive hard to give quality

product to the customers. If this is kind of contamination is happening then its cheating ourselves rather than

cheating the customer because we are spoiling the environment in this way. Lets strive hard & make serious

endeavors to wards ecofriendly processing.

Ashish Kumar

Industrial Enzymes Dept, Marketing & Technical Services,

Biocon Ltd., Bangalore – 560100 India. Email : Ashish.kumar@biocon.com Phone : 080-28082108

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