title: Dynamics of organohalide-respiring bacteria and their genes following in-situ chemical oxidation of chlorinated ethenes and biostimulation.
abstract: Application of Fenton's reagent and enhanced reductive dechlorination are currently the most common remediation strategies resulting in removal of chlorinated ethenes. In this study, the influence of such techniques on organohalide-respiring bacteria was assessed at a site contaminated by chlorinated ethenes using a wide spectrum of molecular genetic markers, including 16S rRNA gene of the organohalide-respiring bacteria Dehaloccocoides spp., Desulfitobacterium and Dehalobacter; reductive dehalogenase genes (vcrA, bvcA) responsible for dechlorination of vinyl chloride and sulphate-reducing and denitrifying bacteria. In-situ application of hydrogen peroxide to induce a Fenton-like reaction caused an instantaneous decline in all markers below detection limit. Two weeks after application, the bvcA gene and Desulfitobacterium relative abundance increased to levels significantly higher than those prior to application. No significant decrease in the concentration of a range of chlorinated ethenes was observed due to the low hydrogen peroxide dose used. A clear increase in marker levels was also observed following in-situ application of sodium lactate, which resulted in a seven-fold increase in Desulfitobacterium and a three-fold increase in Dehaloccocoides spp. after 70 days. An increase in the vcrA gene corresponded with increase in Dehaloccocoides spp. Analysis of selected markers clearly revealed a positive response of organohalide-respiring bacteria to biostimulation and unexpectedly fast recovery after the Fenton-like reaction.
authors.affiliation: Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic. Electronic address: iva.dolinova@tul.cz.
authors.forename: Iva
authors.initials: I
authors.lastname: Dolinová
authors.affiliation: Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic. Electronic address: marie.czinnerova@tul.cz.
authors.forename: Marie
authors.initials: M
authors.lastname: Czinnerová
authors.affiliation: Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic. Electronic address: lukas.dvorak@tul.cz.
authors.forename: Lukáš
authors.initials: L
authors.lastname: Dvořák
authors.affiliation: Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic. Electronic address: vojtech.stejskal@yahoo.com.
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Stejskal
authors.affiliation: Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic. Electronic address: alena.sevcu@tul.cz.
authors.forename: Alena
authors.initials: A
authors.lastname: Ševců
authors.affiliation: Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic. Electronic address: miroslav.cernik@tul.cz.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Černík
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002384:Catalysis; D002713:Chlorine / Q000378:metabolism*; D005819:Genetic Markers / Q000235:genetics; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D010084:Oxidation-Reduction; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019354:Sodium Lactate / Q000008:administration & dosage / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D005819:Genetic Markers; D006843:Hydrocarbons, Chlorinated; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; D002713:Chlorine; D019354:Sodium Lactate
keywords: Biodegradation; Chlorinated ethenes; Organohalide respiration; Organohalide-respiring markers; qPCR