Plasmid-mediated formaldehyde resistance in Escherichia coli: Characterization of resistance gene

The formaldehyde resistance mechanisms in the formaldehyde-resistant strain Escherichia coli VU3695 were investigated, A large (4,6-kb) plasmid DNA fragment encompassing the formaldehyde resistance gene was sequenced, A single 1,107-bp open reading frame encoding a glutathione- and NAD-dependent formaldehyde dehydrogenase was identified and sequenced, and the enzyme was expressed in an in vitro assay and purified, Amino acid sequence homology studies showed 62.4 to 63.2% identity with class III alcohol dehydrogenases isolated from horse, human, and rat livers, We demonstrated that the resistance mechanism in the formaldehyde-resistant strain E. coli W3695 and in other formaldehyde-resistant members of the family Enterobacteriaceae is based on the enzymatic degradation of formaldehyde by a formaldehyde dehydrogenase.