| Title | Metagenomic Analysis Reveals Microbial Interactions at the Biocathode of a Bioelectrochemical System Capable of Simultaneous Trichloroethylene and Cr(VI) Reduction |
| Abstract | Bioelectrochemical systems (BES) are attractive and versatile options for the bioremediation of organic or inorganic pollutants, including trichloroethylene (TCE) and Cr(VI), often found as co-contaminants in the environment. The elucidation of the microbial players' role in the bioelectroremediation processes for treating multicontaminated groundwater is still a research need that attracts scientific interest. In this study, 16S rRNA gene amplicon sequencing and whole shotgun metagenomics revealed the leading microbial players and the primary metabolic interactions occurring in the biofilm growing at the biocathode where TCE reductive dechlorination (RD), hydrogenotrophic methanogenesis, and Cr(VI) reduction occurred. The presence of Cr(VI) did not negatively affect the TCE degradation, as evidenced by the RD rates estimated during the reactor operation with TCE (111±2 ?eq/Ld) and TCE/Cr(VI) (146±2 ?eq/Ld). Accordingly, Dehalococcoides mccartyi, the primary biomarker of the RD process, was found on the biocathode treating both TCE (7.82E+04±2.9E+04 16S rRNA gene copies g graphite) and TCE/Cr(VI) (3.2E+07±2.37E+0716S rRNA gene copies g graphite) contamination. The metagenomic analysis revealed a selected microbial consortium on the TCE/Cr(VI) biocathode. D. mccartyi was the sole dechlorinating microbe with H uptake as the only electron supply mechanism, suggesting that electroactivity is not a property of this microorganism. Methanobrevibacter arboriphilus and Methanobacterium formicicum also colonized the biocathode as H consumers for the CH production and cofactor suppliers for D. mccartyi cobalamin biosynthesis. Interestingly, M. formicicum also harbors gene complexes involved in the Cr(VI) reduction through extracellular and intracellular mechanisms. |
| Source | Frontiers in microbiology 12 |
| Keywords | bioelectrochemical remediationCr(VI) reductionDehalococcoides mccartyiMethanobacterium formicicumMethanobrevibacter arboriphilusreductive dechlorination |
| Journal | Frontiers in microbiology |
| Editor | Frontiers Research Foundation,, Lausanne, Svizzera |
| Year | 2021 |
| Type | Articolo in rivista |
| DOI | 10.3389/fmicb.2021.747670 |
| Authors | Matturro, Bruna; Zepilli, Marco; Lai, Agnese; Majone, Mauro; Rossetti, Simona |
| Text | 461167 2021 10.3389/fmicb.2021.747670 Scopus 2 s2.0 85117108192 bioelectrochemical remediation Cr VI reduction Dehalococcoides mccartyi Methanobacterium formicicum Methanobrevibacter arboriphilus reductive dechlorination Metagenomic Analysis Reveals Microbial Interactions at the Biocathode of a Bioelectrochemical System Capable of Simultaneous Trichloroethylene and Cr VI Reduction Matturro, Bruna; Zepilli, Marco; Lai, Agnese; Majone, Mauro; Rossetti, Simona Istituto di Ricerca sulle Acque, Italy; Sapienza Universita di Roma Bioelectrochemical systems BES are attractive and versatile options for the bioremediation of organic or inorganic pollutants, including trichloroethylene TCE and Cr VI , often found as co contaminants in the environment. The elucidation of the microbial players role in the bioelectroremediation processes for treating multicontaminated groundwater is still a research need that attracts scientific interest. In this study, 16S rRNA gene amplicon sequencing and whole shotgun metagenomics revealed the leading microbial players and the primary metabolic interactions occurring in the biofilm growing at the biocathode where TCE reductive dechlorination RD , hydrogenotrophic methanogenesis, and Cr VI reduction occurred. The presence of Cr VI did not negatively affect the TCE degradation, as evidenced by the RD rates estimated during the reactor operation with TCE 111±2 eq/Ld and TCE/Cr VI 146±2 eq/Ld . Accordingly, Dehalococcoides mccartyi, the primary biomarker of the RD process, was found on the biocathode treating both TCE 7.82E 04±2.9E 04 16S rRNA gene copies g graphite and TCE/Cr VI 3.2E 07±2.37E 0716S rRNA gene copies g graphite contamination. The metagenomic analysis revealed a selected microbial consortium on the TCE/Cr VI biocathode. D. mccartyi was the sole dechlorinating microbe with H uptake as the only electron supply mechanism, suggesting that electroactivity is not a property of this microorganism. Methanobrevibacter arboriphilus and Methanobacterium formicicum also colonized the biocathode as H consumers for the CH production and cofactor suppliers for D. mccartyi cobalamin biosynthesis. Interestingly, M. formicicum also harbors gene complexes involved in the Cr VI reduction through extracellular and intracellular mechanisms. 12 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85117108192 origin=inward Articolo in rivista Frontiers Research Foundation, 1664 302X Frontiers in microbiology Frontiers in microbiology Front. microbiol. Frontiers in microbiology bruna.matturro MATTURRO BRUNA |
