Question

How do aldehydes kill bacteria?

Answer 1

Aldehydes kill bacteria mainly by forming protein-protein crosslinks.

Explanation:

The links form between the amine groups of amino acids (mainly lysine) in one chain and the `"N"` atoms in the peptide linkages of another chain..

For example, here's how formaldehyde works.

1. Formaldehyde exists in solution as methylene glycol.

`"H"_2"C=O" + "H"_2"O" → underbrace("HO-CH"_2"-OH")_color(red)("methylene glycol")`

2. The methylene glycol reacts with the amino group of a protein.

`"Protein-NH"_2 + "HOCH"_2"OH" → "Protein-NH-CH"_2"-OH" + "H"_2"O"`

3. A methylene bridge forms with another protein chain.

`"Protein-NH-CH"_2"-OH" + "H-Protein" → "Protein-NH-CH"_2"-Protein" + "H"_2"O"`

The protein-protein cross linkages severely disrupt the abilities of the bacteria to propagate and to function.