Environmental Engineering PhD Candidate
University of Iowa
Christian is a National Institute of Environmental Health Sciences (NIEHS) Trainee in the Department of Civil & Environmental Engineering at the University of Iowa. He is studying bioremediation of sediments contaminated with polychlorinated biphenyls (PCBs). Christian is determined to play a part in the design and development of an economically sustainable, ecologically friendly, and socially equitable future.
PCB Biodegradation Enhanced by a Phytogenic Biosurfactant
Some microorganisms are capable of rapidly biodegrading most polychlorinated biphenyl (PCB) congeners when they are freely dissolved in liquid but cannot degrade PCB congeners having four or more chlorine substituents in sediment slurry. Results from laboratory bioreactor experiments with sediment collected from a PCB-contaminated field site show that biodegradation can be enhanced in the presence of a plant-derived biosurfactant called 'saponin'. The experiments evaluated strain LB400’s ability to degrade PCBs in absence of sediment and in PCB-contaminated sediment slurry both with and without saponin. In absence of sediment, microbes transformed 76% total PCBs within seven days, spanning all homolog groups. In sediment bioreactors without saponin, only 7% of PCBs were transformed. In bioreactors with saponin, biodegradation of di-, tri-, and tetrachlorobiphenyls was significantly enhanced, relative to the treatments without saponin. These findings are important because they may help to inform strategies for bioaugmentation/biostimulation of legacy-contaminated sediments.