Isolation and Characterization of an Alcohol Dehydrogenase Gene from the Octylphenol Polyethoxylate Degrader Pseudomonas putida S-5

Abstract

Octylphenol polyethoxylate (OPEO_n) biodegradation by Pseudomonas putida S-5 under aerobic conditions is initiated by the oxidation of its terminal alcohol group by alcohol dehydrogenase. A DNA fragment, containing an alcohol dehydrogenase gene (adh1), was isolated using a combination of degenerate PCR and inverse PCR. The predicted translation product of adh1 showed significant sequence similarity to bacterial alcohol dehydrogenases. Furthermore, a flavin-binding motif and signature patterns conserved in type III FAD-dependent alcohol oxidases were detected. Two open reading frames (ORFs) were found upstream of adh1, encoding a putative acyl-CoA synthetase and a putative esterase. Downstream of adh1 and located on the opposite strand was an ORF encoding a putative aldehyde dehydrogenase. Transcription analysis using RT-PCR showed that adh1 is cotranscribed with the putative acyl-CoA synthetase and esterase genes during growth on OPEO_n. ADH1 overproduced in Escherichia coli exhibited activity not only toward various alcohols, including OPEO_ns, but also toward primary aliphatic and aromatic aldehydes.