{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/33412"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/33412","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Investigating the Functional Response of a Subsurface Biofilm Community to Xenobiotic Stress","abstract":"Biologically-mediated subsurface remediation by biofilm communities is a poorly understood process that is spatially and temporally dynamic. Two microbial responses, catabolism and the stress response glutathione-gated potassium efflux (GGKE), to benzene, pentachlorophenol (PCP), or Cd exposure were studied in up-flow sand columns to examine the contribution of each response to the overall functional response of a subsurface biofilm. Benzene was catabolized in the aerobic zone, and did not activate the GGKE response, and exhibited the highest biomass concentrations of all columns. PCP was not catabolized during this study, but was found to elicit two responses, oxidative phosphorylation uncoupling and GGKE, that appeared to be concentration dependent. Oxidative uncoupling was the controlling metabolic response up to 10 mg/L PCP, while the GGKE stress response was activated near 20 mg/L PCP. PCP column biomass did not show long-term biomass detachment, although immediate detachment occurred during initial GGKE activation. Cd column biomass activated the GGKE response as perturbing Cd concentrations increased. Extracellular polymeric substance (EPS)-Cd complexation was a possible detoxification mechanism, as biomass concentrations did not decrease with increasing Cd concentration, and increased as Cd concentrations decreased. Results of this study suggested that the increased exposure of electrophilic contaminants to sand column biomass did not cause biomass detachment.","abstract_html":"Biologically-mediated subsurface remediation by biofilm communities is a poorly understood process that is spatially and temporally dynamic. Two microbial responses, catabolism and the stress response glutathione-gated potassium efflux (GGKE), to benzene, pentachlorophenol (PCP), or Cd exposure were studied in up-flow sand columns to examine the contribution of each response to the overall functional response of a subsurface biofilm. Benzene was catabolized in the aerobic zone, and did not activate the GGKE response, and exhibited the highest biomass concentrations of all columns. PCP was not catabolized during this study, but was found to elicit two responses, oxidative phosphorylation uncoupling and GGKE, that appeared to be concentration dependent. Oxidative uncoupling was the controlling metabolic response up to 10 mg/L PCP, while the GGKE stress response was activated near 20 mg/L PCP. PCP column biomass did not show long-term biomass detachment, although immediate detachment occurred during initial GGKE activation. Cd column biomass activated the GGKE response as perturbing Cd concentrations increased. Extracellular polymeric substance (EPS)-Cd complexation was a possible detoxification mechanism, as biomass concentrations did not decrease with increasing Cd concentration, and increased as Cd concentrations decreased. Results of this study suggested that the increased exposure of electrophilic contaminants to sand column biomass did not cause biomass detachment.","abstract_has_math":false,"creators":["Rhodes, Rachelle Renee"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Environmental Planning","degree_department":"Environmental Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Love, Nancy G."],"committee_members":["Schreiber, Madeline E.","Novak, John T."],"year":2004,"date_issued":"2004-05-12","date_published":"2004-05-12","updated_at":"2026-07-22T22:18:42Z","subjects":["GGKE","Biofilm","functional response","potassium"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06042004-075312"],"render_values":[{"text":"etd-06042004-075312","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/33412","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Love, Nancy G."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Schreiber, Madeline E.","Novak, John T."]},{"key":"dc:contributor.department","label":"Department","values":["Environmental Engineering"]},{"key":"dc:creator","label":"Author","values":["Rhodes, Rachelle Renee"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:39:20Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:39:20Z","2004-07-21"]},{"key":"dc:date.issued","label":"Date","values":["2004-05-12"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Environmental Planning"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["GGKE","Biofilm","functional response","potassium"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06042004-075312"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/33412"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Biologically-mediated subsurface remediation by biofilm communities is a poorly understood process that is spatially and temporally dynamic. Two microbial responses, catabolism and the stress response glutathione-gated potassium efflux (GGKE), to benzene, pentachlorophenol (PCP), or Cd exposure were studied in up-flow sand columns to examine the contribution of each response to the overall functional response of a subsurface biofilm. Benzene was catabolized in the aerobic zone, and did not activate the GGKE response, and exhibited the highest biomass concentrations of all columns. PCP was not catabolized during this study, but was found to elicit two responses, oxidative phosphorylation uncoupling and GGKE, that appeared to be concentration dependent. Oxidative uncoupling was the controlling metabolic response up to 10 mg/L PCP, while the GGKE stress response was activated near 20 mg/L PCP. PCP column biomass did not show long-term biomass detachment, although immediate detachment occurred during initial GGKE activation. Cd column biomass activated the GGKE response as perturbing Cd concentrations increased. Extracellular polymeric substance (EPS)-Cd complexation was a possible detoxification mechanism, as biomass concentrations did not decrease with increasing Cd concentration, and increased as Cd concentrations decreased. Results of this study suggested that the increased exposure of electrophilic contaminants to sand column biomass did not cause biomass detachment."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Investigating the Functional Response of a Subsurface Biofilm Community to Xenobiotic Stress"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Love, Nancy G."],"dc:contributor.committeemember":["Schreiber, Madeline E.","Novak, John T."],"dc:contributor.department":["Environmental Engineering"],"dc:creator":["Rhodes, Rachelle Renee"],"dc:date.accessioned":["2014-03-14T20:39:20Z"],"dc:date.available":["2014-03-14T20:39:20Z","2004-07-21"],"dc:date.issued":["2004-05-12"],"dc:description.abstract":["Biologically-mediated subsurface remediation by biofilm communities is a poorly understood process that is spatially and temporally dynamic. Two microbial responses, catabolism and the stress response glutathione-gated potassium efflux (GGKE), to benzene, pentachlorophenol (PCP), or Cd exposure were studied in up-flow sand columns to examine the contribution of each response to the overall functional response of a subsurface biofilm. Benzene was catabolized in the aerobic zone, and did not activate the GGKE response, and exhibited the highest biomass concentrations of all columns. PCP was not catabolized during this study, but was found to elicit two responses, oxidative phosphorylation uncoupling and GGKE, that appeared to be concentration dependent. Oxidative uncoupling was the controlling metabolic response up to 10 mg/L PCP, while the GGKE stress response was activated near 20 mg/L PCP. PCP column biomass did not show long-term biomass detachment, although immediate detachment occurred during initial GGKE activation. Cd column biomass activated the GGKE response as perturbing Cd concentrations increased. Extracellular polymeric substance (EPS)-Cd complexation was a possible detoxification mechanism, as biomass concentrations did not decrease with increasing Cd concentration, and increased as Cd concentrations decreased. Results of this study suggested that the increased exposure of electrophilic contaminants to sand column biomass did not cause biomass detachment."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-06042004-075312"],"dc:identifier.uri":["http://hdl.handle.net/10919/33412"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["GGKE","Biofilm","functional response","potassium"],"dc:title":["Investigating the Functional Response of a Subsurface Biofilm Community to Xenobiotic Stress"],"dc:type":["Thesis"],"thesis:degree_discipline":["Environmental Planning"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:42Z"}