{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T13:28:45Z","timestamp":1787146125841,"version":"build-2736575974"},"reference-count":84,"publisher":"American Society for Microbiology","issue":"8","license":[{"start":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T00:00:00Z","timestamp":1787097600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T00:00:00Z","timestamp":1787097600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/100000006","name":"Office of Naval Research","doi-asserted-by":"publisher","award":["N000140610090"],"award-info":[{"award-number":["N000140610090"]}],"id":[{"id":"10.13039\/100000006","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100006370","name":"Small Business Innovation Research","doi-asserted-by":"publisher","award":["2R44ES032365"],"award-info":[{"award-number":["2R44ES032365"]}],"id":[{"id":"10.13039\/100006370","id-type":"DOI","asserted-by":"publisher"}]},{"name":"University of Maryland School of Pharmacy Mass Spectrometry Center","award":["SOP1841-IQB2014"],"award-info":[{"award-number":["SOP1841-IQB2014"]}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Appl Environ Microbiol"],"published-print":{"date-parts":[[2026,8,19]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      Polychlorinated biphenyls (PCBs) and chlorinated ethenes, such as perchloroethene (PCE), are persistent environmental contaminants that pose significant ecological and health risks.\n                      <jats:italic toggle=\"yes\">Dehalobium chlorocoercia<\/jats:italic>\n                      strain DF-1 can reductively dechlorinate both PCEs and PCBs, offering a sustainable remediation strategy. However, its large-scale cultivation has been limited by dependence on an undefined growth-stimulatory factor produced by\n                      <jats:italic toggle=\"yes\">Pseudodesulfovibrio<\/jats:italic>\n                      sp. (DSV). Filtrates of DSV-autoclaved cultures passed through a 10-kDa cutoff filter enhanced growth-linked dechlorination of DF-1, indicating that the active component is a small-molecular-weight, nonsecretory, thermostable compound. Acid precipitation of the autoclaved DSV extract yielded a glycolipid-enriched fraction that also supported DF-1 growth; in parallel, the model biosurfactant surfactin stimulated DF-1 activity, consistent with a biosurfactant-mediated effect. Liquid chromatography coupled to high-resolution tandem mass spectrometry analysis of the acid-precipitated fraction detected ions and fragmentation patterns consistent with multiple rhamnolipid congeners, including mono- and di-rhamnolipids with C8\u2013C12 acyl chains. Both glycolipid-enriched extract and commercial rhamnolipids substituted for DSV extracts, stimulating DF-1 growth-linked reductive dechlorination of PCE, 2,3,4,5-tetrachlorobiphenyl (PCB 61), and 2,2\u2032,3,3\u2032,4,5,5\u2032,6-Octachlorobiphenyl (PCB 199) in a concentration-dependent manner. Maximal DF-1 growth-linked dechlorination rates were observed at submicellar rhamnolipid concentrations, whereas higher concentrations were inhibitory. Rhamnolipid supplementation reduced growth lag and increased DF-1 biomass and dechlorination rates by solubilizing hydrophobic electron acceptors, thereby increasing their bioavailability in the medium. These findings suggest that rhamnolipid-type biosurfactants in\n                      <jats:italic toggle=\"yes\">Pseudodesulfovibrio<\/jats:italic>\n                      sp. extracts have a role in enhancing the growth of DF-1 and demonstrate that commercial rhamnolipid supplementation can replace undefined coculture extracts, enabling reproducible large-scale cultivation of DF-1 for bioaugmentation of PCB- and PCE-contaminated environments.\n                    <\/jats:p>\n                    <jats:sec>\n                      <jats:title>IMPORTANCE<\/jats:title>\n                      <jats:p>\n                        Polychlorinated biphenyls (PCBs) and chlorinated ethenes remain widespread contaminants that are difficult to remove with conventional technologies, creating a need for scalable bioremediation strategies.\n                        <jats:italic toggle=\"yes\">Dehalobium chlorocoercia<\/jats:italic>\n                        DF-1 is one of the few isolates available that can reductively dechlorinate both PCBs and PCE, but its application has been hindered by reliance on undefined extracts from a\n                        <jats:italic toggle=\"yes\">Pseudodesulfovibrio<\/jats:italic>\n                        sp. This study shows that the key stimulatory activity is associated with rhamnolipid-type glycolipid biosurfactants released from\n                        <jats:italic toggle=\"yes\">Pseudodesulfovibrio<\/jats:italic>\n                        sp. cells upon lysis. Glycolipid-enriched extracts and defined commercial rhamnolipids enhance DF-1 growth-linked dechlorination of PCE and PCB congeners in a dose-dependent manner, primarily by increasing the bioavailability of hydrophobic electron acceptors. By replacing complex coculture extracts with a defined biosurfactant supplement, these findings remove a major barrier to reproducible, large-scale cultivation of DF-1 and advance the feasibility of bioaugmentation for PCB- and PCE-contaminated environments.\n                      <\/jats:p>\n                    <\/jats:sec>\n                  <\/jats:sec>","DOI":"10.1128\/aem.00841-26","type":"journal-article","created":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T13:01:17Z","timestamp":1785762077000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Rhamnolipid-augmented medium enhances growth of\n                    <i>Dehalobium chlorocoercia<\/i>\n                    on chloroethenes and polychlorinated biphenyls"],"prefix":"10.1128","volume":"92","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8169-6817","authenticated-orcid":true,"given":"Vijay","family":"Hemmadi","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/02qskvh78","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Randhir S.","family":"Makkar","sequence":"additional","affiliation":[{"name":"Enzylignol Inc","place":["Ladson, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0460-0380","authenticated-orcid":true,"given":"Jace W.","family":"Jones","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6669-3231","authenticated-orcid":true,"given":"Christopher W.","family":"Marshall","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04gr4te78","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Biological Sciences, Marquette University","place":["Milwaukee, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4692-2388","authenticated-orcid":true,"given":"Allen R.","family":"Place","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04dqdxm60","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Sciences","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1873-0680","authenticated-orcid":true,"given":"Harold D.","family":"May","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/012jban78","id-type":"ROR","asserted-by":"publisher"}],"name":"Hollings Marine Laboratory, Medical University of South Carolina","place":["Charleston, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8920-9278","authenticated-orcid":true,"given":"Kevin R.","family":"Sowers","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/02qskvh78","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/s1369-5274(02)00323-5"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1263\/jbb.105.433"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1021\/es00169a004"},{"key":"e_1_3_4_5_2","first-page":"443","volume-title":"Dehalogenation","author":"Bedard DL","year":"2005","unstructured":"Bedard DL. 2005. 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