Project Summary/Abstract
Challenges exist in bioremediation of halogenated contaminants, including low donor utilization efficiency and
slow dehalogenation, low dehalogenation activity and degree for the emerging per- and polyfluorinated
substances, as well as the difficulty in simultaneously treating co-contaminants. To address those challenges,
this project integrates advances in materials sciences and microbial reductive dehalogenation and proposes a
synergistic materials-microbe interface that can achieve faster, deeper, and air-tolerant reductive
dehalogenation. Charge transfer mechanisms in the proposed electricity-driven materials-microbe hybrid will be
investigated, which will guide the design and optimization of novel nano- and micro-scale materials to enhance
the mass-transport efficiency and accelerate dehalogenation. The local electron donor levels can be stably
maintained at low levels, favoring dehalorespiring microorganisms over methanogens and homoacetogens,
leading to enhanced electron donor utilization. A systems-level understanding of microorganisms enriched in the
bioelectrochemical system and genes/enzymes responsible for deeper defluorination will be obtained with omics
techniques. Novel reductive defluorination products/pathways and synergistic interactions between microbial
and electrochemical defluorination will be elucidated using advanced analytical tools such as high-resolution
mass spectrometry. Furthermore, an air-tolerant materials-microbe framework for reductive dehalogenation will
be developed using a recently designed microwire array electrodes and implemented to achieve concurrent
oxidation of the co-contaminant 1,4-dioxane in an open system. This project will significantly advance the
mechanistic understanding of the accelerated and deeper reductive dehalogenation at the synergistic materials-
microbe interface. This hybrid framework is powered by electricity that can be generated from sustainable solar
energy and may lower the cost by reducing the requirement of fermentable organics and by combining the
anaerobic and aerobic remediation processes. The successful demonstration of this new paradigm of
bioremediation will potentially lead to future applications for cleaning up the halogenated contaminants and co-
contaminants in subsurface environments. The developed materials-microbe framework is also highly
transformable to the bioremediation processes of other environmental contaminants.
