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TitleReductive dechlorination of tetrachloroethene in marine sediments: Biodiversity and dehalorespiring capabilities of the indigenous microbes
AbstractChlorinated compounds pose environmental concerns due to their toxicity and wide distribution in several matrices. Microorganisms specialized in leading anaerobic reductive dechlorination (RD) processes, including Dehalococcoides mccartyi (Dhc), are able to reduce chlorinated compounds to harmless products or to less toxic forms. Here we report the first detailed study dealing with the RD potential of heavy polluted marine sediment by evaluating the biodegradation kinetics together with the composition, dynamics and activity of indigenous microbial population. A microcosm study was conducted under strictly anaerobic conditions on marine sediment collected near the marine coast of Sarno river mouth, one of the most polluted river in Europe. Tetrachloroethene (PCE), used as model pollutant, was completely converted to ethene within 150 days at reductive dechlorination rate equal to 0.016 meq L- 1 d- 1. Consecutive spikes of PCE allowed increasing the degradation kinetics up to 0.1 meq L- 1 d- 1 within 20 days. Strictly anaerobiosis and repeated spikes of PCE stimulated the growth of indigenous Dhc cells (growth yield of ~ 7.0E + 07 Dhc cells per ?M Cl- 1 released). Dhc strains carrying the reductive dehalogenase genes tceA and vcrA were detected in the original marine sediment and their number increased during the treatment as demonstrated by the high level of tceA expression at the end of the microcosm study (2.41E + 05 tceA gene transcripts g- 1). Notably, the structure of the microbial communities was fully described by Catalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) as wells as the dynamics of the dechlorinating bacteria during the microcosms operation. Interestingly, a direct role of Dhc cells was ascertained suggesting the existence of strains adapted at salinity conditions. Additionally, non-Dhc Chloroflexi were retrieved in the original sediment and were kept stable over time suggesting their likely flanking role of the RD process.
SourceScience of the total environment 545-546, pp. 445–452
KeywordsBiodegradationDehalococcoides mccartyiMarine sedimentPCEReductive dechlorination
JournalScience of the total environment
EditorElsevier, Lausanne ;, Paesi Bassi
Year2016
TypeArticolo in rivista
DOI10.1016/j.scitotenv.2015.12.098
AuthorsMatturro B.; Presta E.; Rossetti S.
Text348630 2016 10.1016/j.scitotenv.2015.12.098 Scopus 2 s2.0 84952685416 ISI Web of Science WOS WOS 000369493000046 Biodegradation Dehalococcoides mccartyi Marine sediment PCE Reductive dechlorination Reductive dechlorination of tetrachloroethene in marine sediments Biodiversity and dehalorespiring capabilities of the indigenous microbes Matturro B.; Presta E.; Rossetti S. Water Research Institute, IRSA CNR, Via Salaria km 29, 300, Monterotondo, RM, Italy Chlorinated compounds pose environmental concerns due to their toxicity and wide distribution in several matrices. Microorganisms specialized in leading anaerobic reductive dechlorination RD processes, including Dehalococcoides mccartyi Dhc , are able to reduce chlorinated compounds to harmless products or to less toxic forms. Here we report the first detailed study dealing with the RD potential of heavy polluted marine sediment by evaluating the biodegradation kinetics together with the composition, dynamics and activity of indigenous microbial population. A microcosm study was conducted under strictly anaerobic conditions on marine sediment collected near the marine coast of Sarno river mouth, one of the most polluted river in Europe. Tetrachloroethene PCE , used as model pollutant, was completely converted to ethene within 150 days at reductive dechlorination rate equal to 0.016 meq L 1 d 1. Consecutive spikes of PCE allowed increasing the degradation kinetics up to 0.1 meq L 1 d 1 within 20 days. Strictly anaerobiosis and repeated spikes of PCE stimulated the growth of indigenous Dhc cells growth yield of 7.0E 07 Dhc cells per M Cl 1 released . Dhc strains carrying the reductive dehalogenase genes tceA and vcrA were detected in the original marine sediment and their number increased during the treatment as demonstrated by the high level of tceA expression at the end of the microcosm study 2.41E 05 tceA gene transcripts g 1 . Notably, the structure of the microbial communities was fully described by Catalysed Reporter Deposition Fluorescence In Situ Hybridization CARD FISH as wells as the dynamics of the dechlorinating bacteria during the microcosms operation. Interestingly, a direct role of Dhc cells was ascertained suggesting the existence of strains adapted at salinity conditions. Additionally, non Dhc Chloroflexi were retrieved in the original sediment and were kept stable over time suggesting their likely flanking role of the RD process. 545 546 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 84952685416 partnerID=q2rCbXpz Matturro et al . STOTEN 2016 Matturro et al STOTEN 2016.pdf Articolo in rivista Elsevier 0048 9697 Science of the total environment Science of the total environment Sci. total environ. simona.rossetti ROSSETTI SIMONA bruna.matturro MATTURRO BRUNA