A wide host-range metagenomic library from a waste water treatment plant yields a novel alcohol/aldehyde dehydrogenase that allows Rhizobium leguminosarum but not Escherichia coli to grow on ethanol

Wexler, Margaret, Bond, Philip L., Richardson, David J. ORCID: https://orcid.org/0000-0002-6847-1832 and Johnston, Andrew W. B. (2005) A wide host-range metagenomic library from a waste water treatment plant yields a novel alcohol/aldehyde dehydrogenase that allows Rhizobium leguminosarum but not Escherichia coli to grow on ethanol. Environmental Microbiology, 7 (12). pp. 1917-1926. ISSN 1462-2912

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Abstract

Using DNA obtained from the metagenome of an anaerobic digestor in a waste water treatment plant, we constructed a gene library cloned in the wide host-range cosmid pLAFR3. One cosmid enabled Rhizobium leguminosarum to grow on ethanol as sole carbon and energy source, this being due to the presence of a gene, termed adhEMeta. The AdhEMeta protein most closely resembles the AdhE alcohol dehydrogenase of Clostridium acetobutylicum, where it catalyses the formation of ethanol and butanol in a two-step reductive process. However, cloned adhEMeta did not confer ethanol utilization ability to Escherichia coli or to Pseudomonas aeruginosa, even though it was transcribed in both these hosts. Further, cell-free extracts of E. coli and R. leguminosarum containing cloned adhEMeta had butanol and ethanol dehydrogenase activities when assayed in vitro. In contrast to the well-studied AdhE proteins of C. acetobutylicum and E. coli, the enzyme specified by adhEMeta is not inactivated by oxygen and it enables alcohol to be catabolized. Cloned adhEMeta did, however, confer one phenotype to E. coli. AdhE– mutants of E. coli fail to ferment glucose and introduction of adhEMeta restored the growth of such mutants when grown under fermentative conditions. These observations show that the use of wide host-range vectors enhances the efficacy with which metagenomic libraries can be screened for genes that confer novel functions.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Biological Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Organisms and the Environment Faculty of Science > Research Groups > Molecular Microbiology Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry
Depositing User:	EPrints Services
Date Deposited:	01 Oct 2010 13:37
Last Modified:	24 Sep 2024 10:01
URI:	https://ueaeprints.uea.ac.uk/id/eprint/1087
DOI:	10.1111/j.1462-2920.2005.00854.x

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