Influence of hexavalent chromium on lactate-enriched Hanford groundwater microbial communities.

Journal Article · Tue Jan 01 04:00:00 EST 2013 · PLoS ONE

DOI:https://doi.org/10.1371/journal.pone.0083909· OSTI ID:1121808

Somenahally, Anil C ^[1]; Mosher, Jennifer J ^[1]; Yuan, Tong ^[2]; Podar, Mircea ^[1]; Phelps, Tommy Joe ^[1]; Brown, Steven D ^[1]; Yang, Zamin Koo ^[1]; Hazen, Terry C ^[1]; Arkin, Adam ^[3]; Palumbo, Anthony Vito ^[1]; Zhou, Jizhong ^[2]; Elias, Dwayne A ^[1]

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1. ORNL
2. University of Oklahoma
3. Lawrence Berkeley National Laboratory (LBNL)

Microbial reduction and immobilization of chromate (Cr(VI)) is a plausible bioremediation strategy. However, higher Cr(VI) concentrations may impose stress on native Cr-reducing communities. We sought to determine if Cr(VI) would influence the lactate enriched native microbial community structure and function in groundwater from the Cr contaminated site at Hanford, WA. Steady state continuous flow bioreactors were amended with lactate and Cr(VI) (0.0, 0.1 and 3.0 mg/L). Microbial growth, metabolites, Cr(VI) concentrations, 16S rRNA gene sequences and GeoChip based functional gene composition in bioreactors were monitored for 15 weeks. Temporal trends and some differences in growth, metabolite profiles, and community composition were observed, largely between Low-Cr and High-Cr bioreactors. In both High-Cr and Low-Cr bioreactors, Cr(VI) was reduced in the bioreactors. With lactate enrichment, the native communities did not significantly differ between Cr concentrations. Native bacterial communities were diverse, whereas after lactate enrichment, Pelosinus spp., and Sporotalea spp., were the most predominant groups in all bioreactors. Similarly, the Archaea diversity significantly decreased from Methanosaeta (35%), Methanosarcina (17%), Halobacteriales (12%), Methanoregula (8%) and others, to mostly Methanosarcina spp. (95%) after lactate enrichment. Composition of several key functional genes was distinct in Low-Cr bioreactors compared to High-Cr. Among the Cr resistant probes (chrA), Burkholderia vietnamiensis, Comamonas testosterone and Ralstonia pickettii proliferated in Cr amended bioreactors. In-situ fermentative conditions facilitated Cr(VI) reduction, and as a result the 3.0 mg/L Cr(VI) did not appear to give chromate reducing strains a competitive advantage for proliferation or for increasing Cr-reduction.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1121808
• Journal Information: PLoS ONE, Journal Name: PLoS ONE Journal Issue: 12 Vol. 8; ISSN 1932-6203
• Country of Publication: United States
• Language: English

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