Sol-Gel-Encapsulated Biofilms on Biochar Effectively Degrade PCBs and Extend Biodegradation Activity under Environmentally Relevant Conditions.
- 1Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, Iowa52242, United States.
- 2IIHR-Hydroscience and Engineering, University of Iowa, 100 C. Maxwell Stanley Hydraulics Laboratory, Iowa City, Iowa52242, United States.
- 3Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa52242, United States.
Abstract
Attaching aerobic, PCB-degrading cells to carbon-based sorbent materials prior to sediment application is a feasible approach for bioaugmenting contaminated sediments to improve remediation strategies. Furthermore, encapsulation of attached cells with a novel, tailored sol-gel material can protect biofilms from unfavorable environmental conditions that interfere with biofilm stability and create stress that threatens long-term biofilm viability. We systematically evaluated biodegradation and sorption of three PCB congeners (PCBs 4, 18, and 52), quantified biphenyl dioxygenase gene (bphA) abundance and expression, and characterized sol-gel and biofilm integrity of sol-gel-coated PCB-degrading biofilms on black carbon over 45 days under environmentally relevant conditions. Sol-gel coatings did not significantly inhibit PCB sorption to the black carbon, and sol-gel-coated biofilms achieved 72-92% PCB removal within 45 days, comparable to uncoated biofilms (>91%). Although PCB biodegradation rates in uncoated biofilms were >5-fold higher than sol-gel-coated biofilms, sol-gel-coated biofilms maintained >2-fold higher bphA expression levels than uncoated biofilms after 45 days of treatment. Lower temperature (10 °C) decreased PCB biodegradation extent regardless of sol-gel coating but significantly increased (10-fold higher) bphA expression levels in sol-gel-coated biofilms. Salinity (20 g/L) negatively impacted bphA expression levels (>13-fold lower after 45 days) for all treatments. Our novel sol-gel design demonstrates dual benefits: to sorb PCBs from the environment to biofilms and provide carbon sources for PCB cometabolism, thereby protecting and supporting biofilms for potential extended activity in future field applications.
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BibTeX
@article{dong2026solgelencapsulated,
title = {{Sol-Gel-Encapsulated Biofilms on Biochar Effectively Degrade PCBs and Extend Biodegradation Activity under Environmentally Relevant Conditions.}},
author = {Qin Dong and Weilun Zhao and Andres Martinez and Rachel F Marek and Keri C Hornbuckle and Xueshu Li and Hans-Joachim Lehmler and Gregory H LeFevre and Timothy E Mattes},
journal = {Environmental science \& technology},
year = {2026},
month = oct,
doi = {10.1021/acs.est.6c02869},
url = {https://europepmc.org/article/MED/42915955},
note = {CC BY},
}
RIS
TY - JOUR
TI - Sol-Gel-Encapsulated Biofilms on Biochar Effectively Degrade PCBs and Extend Biodegradation Activity under Environmentally Relevant Conditions.
AU - Qin Dong
AU - Weilun Zhao
AU - Andres Martinez
AU - Rachel F Marek
AU - Keri C Hornbuckle
AU - Xueshu Li
AU - Hans-Joachim Lehmler
AU - Gregory H LeFevre
AU - Timothy E Mattes
PY - 2026
DA - 2026/10/01
JO - Environmental science & technology
DO - 10.1021/acs.est.6c02869
UR - https://europepmc.org/article/MED/42915955
AB - Attaching aerobic, PCB-degrading cells to carbon-based sorbent materials prior to sediment application is a feasible approach for bioaugmenting contaminated sediments to improve remediation strategies. Furthermore, encapsulation of attached cells with a novel, tailored sol-gel material can protect biofilms from unfavorable environmental conditions that interfere with biofilm stability and create stress that threatens long-term biofilm viability. We systematically evaluated biodegradation and sorption of three PCB congeners (PCBs 4, 18, and 52), quantified biphenyl dioxygenase gene (bphA) abundance and expression, and characterized sol-gel and biofilm integrity of sol-gel-coated PCB-degrading biofilms on black carbon over 45 days under environmentally relevant conditions. Sol-gel coatings did not significantly inhibit PCB sorption to the black carbon, and sol-gel-coated biofilms achieved 72-92% PCB removal within 45 days, comparable to uncoated biofilms (>91%). Although PCB biodegradation rates in uncoated biofilms were >5-fold higher than sol-gel-coated biofilms, sol-gel-coated biofilms maintained >2-fold higher bphA expression levels than uncoated biofilms after 45 days of treatment. Lower temperature (10 °C) decreased PCB biodegradation extent regardless of sol-gel coating but significantly increased (10-fold higher) bphA expression levels in sol-gel-coated biofilms. Salinity (20 g/L) negatively impacted bphA expression levels (>13-fold lower after 45 days) for all treatments. Our novel sol-gel design demonstrates dual benefits: to sorb PCBs from the environment to biofilms and provide carbon sources for PCB cometabolism, thereby protecting and supporting biofilms for potential extended activity in future field applications.
SN - 0013-936X
SN - 1520-5851
ER -