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Media type:
E-Article
Title:
Laboratory evolution of Geobacter sulfurreducens for enhanced growth on lactate via a single-base-pair substitution in a transcriptional regulator
Contributor:
Summers, Zarath M;
Ueki, Toshiyuki;
Ismail, Wael;
Haveman, Shelley A;
Lovley, Derek R
imprint:
Oxford University Press (OUP), 2012
Published in:The ISME Journal
Language:
English
DOI:
10.1038/ismej.2011.166
ISSN:
1751-7362;
1751-7370
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title>
<jats:p>The addition of organic compounds to groundwater in order to promote bioremediation may represent a new selective pressure on subsurface microorganisms. The ability of Geobacter sulfurreducens, which serves as a model for the Geobacter species that are important in various types of anaerobic groundwater bioremediation, to adapt for rapid metabolism of lactate, a common bioremediation amendment, was evaluated. Serial transfer of five parallel cultures in a medium with lactate as the sole electron donor yielded five strains that could metabolize lactate faster than the wild-type strain. Genome sequencing revealed that all five strains had non-synonymous single-nucleotide polymorphisms in the same gene, GSU0514, a putative transcriptional regulator. Introducing the single-base-pair mutation from one of the five strains into the wild-type strain conferred rapid growth on lactate. This strain and the five adaptively evolved strains had four to eight-fold higher transcript abundance than wild-type cells for genes for the two subunits of succinyl-CoA synthase, an enzyme required for growth on lactate. DNA-binding assays demonstrated that the protein encoded by GSU0514 bound to the putative promoter of the succinyl-CoA synthase operon. The binding sequence was not apparent elsewhere in the genome. These results demonstrate that a single-base-pair mutation in a transcriptional regulator can have a significant impact on the capacity for substrate utilization and suggest that adaptive evolution should be considered as a potential response of microorganisms to environmental change(s) imposed during bioremediation.</jats:p>