| Start Date: | 6/18/2015 | Start Time: | 1:00 PM |
| End Date: | 6/18/2015 | End Time: | 3:00 PM |
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Event Description
Deciphering the ecological roles of supportive microorganisms forDehalococcoides mccartyi in dechlorinating microbial communities
Dr. Yujie Men: Eawag, Swiss Federal Institute of Aquatic Science and Technology
Abstract:
Chlorinated solvents, typically tetra-/tri-chloroethenes (PCE/TCE) are common groundwater contaminants in the U.S. In situbioremediation via reductive dechlorination, as a cost-effective approach, has been applied to clean up polluted sites and protect public health from further exposure. Dehalococcoides mccartyi is the key microorganism that carries out the complete dechlorination to the benign end product ethene. However, the slow growth and fastidious nutrient requirements, such as external corrinoid co-factors limit its abundance and activities. Given that faster and more robust growth of D. mccartyi has been observed in communities, the overall goal of this study is to identify microorganisms supporting the growth of D. mccartyi with corrinoid co-factors, hence to identify potential diagnostic biomarkers for chlorinated solvent bioremediation processes. Dechlorinating enrichments without exogenous corrinoids were successfully constructed. Using analytical methods and a suite of molecular tools (i.e. meta-omics, real-time PCR, microarrays), the corrinoids produced in those enrichments were determined, with a predominant form of p-cresolyl cobamide. Pelosinus species were suggested to be the responsible corrinoid-producing bacteria. The microbial interactions between the suggested supportive microorganisms and D. mccartyi were further studied by constructing defined consortia. Results indicate that when the lower ligand of cobalamin was available, D. mccartyi was able to remodel p-cresolyl cobamide produced by Pelosinusspecies into cobalamin, the favorable form for reductive dechlorination via a CbiZ-dependent corrinoid salvaging and remodeling pathway. Potential biomarkers were then suggested for promoting better monitoring and diagnosis, hence more efficient bioremediation processes.
Lecturer Bio:
Dr. Yujie Men is currently a postdoctoral scientist at Eawag, Swiss Federal Institute of Aquatic Science and Technology. Before she joined Eawag in Jan, 2014, she got her B.S. and M.S. in the School of Engineering at Tsinghua University, China, and earned her PhD in Civil and Environmental Engineering, at University of California, Berkeley. Her research interests focus on applying the fundamental knowledge of environmental microbiology and microbial ecology to a variety of environmental engineering applications, such as nitrogen removal, minimization of greenhouse gas emission, and resource recovery from wastes. She will start as assistant professor in the Department of Civil and Environmental Engineering at University of Illinois, Urbana Champaign in Spring, 2016.
Nanoparticle Hybrid Catalysts for Perchlorate Treatment in Water
Dr. Jinyong Liu: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign; Colorado School of Mines
Abstract:
Perchlorate (ClO4-) is an endocrine-disrupting drinking water contaminant, and the nationwide regulation of ClO4- by the U.S. EPA is pending. Our research team has been developing a series of novel biomimetic complex-nanoparticle hybrid catalysts to reduce ClO4- into innocuous Cl- in water at ambient condition. Working mechanisms of these heterogeneous catalysts using rhenium (Re) as the oxygen atom transfer (OAT) center and hydrogenating metals (e.g., Pd) with H2 for electron transfer resemble the processes in biological oxyanion reductases that contain a series of metal complex sites of variable Mo and Fe species. This presentation will report on our in-depth mechanistic insights of these catalysts, as well as rational design and synthesis of various Re complexes with tunable activity towards the preparation of heterogeneous catalyst with further improved sustainability. For example, beyond the traditional knowledge of “ligand enhancement” in metal-catalyzed environmental chemistry, coordination isomerism has been identified in our study as a determining factor of Re complex activity. Synthetic additives and ligand structure design have both been developed to eliminate the less active isomers and selectively harvest the much more active isomers. Rational combination of varied Re complexes and hydrogenation metals have also shown facile engineering controllability of performance and stability of these novel and promising catalysts for environmental applications.
Lecturer Bio:
Dr. Jinyong Liu earned his Ph.D degree in Environmental Engineering from the University of Illinois at Urbana-Champaign. He is currently a postdoctoral researcher in the CEE Department at both UIUC and Colorado School of Mines. He obtained his B.S. in Chemistry and M.S. in Environmental Science and Engineering in Tsinghua University, China. His interests focus on establishing innovative connection between chemistry fundamentals and challenges in environmental engineering and science research, and exploring the Periodic Table for future environmental technologies. His past and current research include homogeneous and heterogeneous catalysis, functional organic and nanostructured materials, phosphorus in aquatic system, and water and wastewater treatment. |
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Location:
Curtis Hall 250A |
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