Abstract
1. Bacterial azoreduction has been shown to be mediated in vitro by a rapid non-enzymic reduction by enzyme-generated reduced flavins. Some other xenobiotics capable of being reduced by bacteria have been examined as substrates for this non-enzymic reduction. 2. p-Nitrobenzoic acid is reduced by non-enzymic ‘azoreductase’ system to p-hydroxylaminobenzoic acid. Some other mechanism is responsible for reduction of the aldehyde groups of vanillin and protocatechuic aldehyde, and the double bonds of o- and m-coumaric acids, by whole rat caecal contents.