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Name: Refik A.
Status: Other
Age: 30s
Location: N/A
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Date: N/A 

I am working for a company producing starch. Before drying process we wash the starch milk with the WASHING WATER. For this the microorganism. Now please answer : How does SO2 effect on the microorganisms (bacteria, yeast and mould)? What is the mechanism of killing or preventing microorganism?

Enzymes are the alpha and omega to biological processes. They take care of all important chemical reactions in a cell. Enzymes are proteins, and like all proteins they consist of chains of amino acids. These chains have to be faulted in a specific way to give the enzyme it's activity. In many enzymes, the structure of the enzyme is ensured by cross-bonding of the amino-acid chains. These cross-bonds consist of double Sulphur bonds.

This introduction was needed to explain the mechanism of sulphur dioxide, SO2. SO2 is reactive to some enzymes and can degrade the sulphur bonds needed for structural stability. Once these bonds are broken the enzyme is inactive. That happens to be the case with some important enzymes, for instance DNA polymerase of bacteria. This enzyme forms the DNA molecules that are needed for each cell division. If DNA polymerase can not do its work (because SO2 has distroyed it), the cell cannot divide, that is the micro-organisms cannot multiply.

And fortunately for us, our DNA polymerase is not sensitive to SO2. This is a simplified explanation of a complicated matter. It is easier to determine THAT a compound can kill microorganisms than to find out HOW.

Trudy Wassenaar

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