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Chao Peng


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I was born and grew up in Sichuan, China. I got my bachelor degree in Geology at China University of Geoscience in Bejing. After graduation, I did an internship at the Center for Geomicrobiology in Aarhus University in Denmark. Thereafter I went to Germany to study for my master degree in Marine Microbiology at the Max-Planck Institute for Marine Microbiology in Bremen. Now I am a PhD student in Geomicrobiology at the University of Tuebingen in Germany, and I am supervised by Prof. Andreas Kappler and Prof. Thomas Borch.

Project Summary

Microbial oxidation of Fe(II)-natural organic material complexes

Iron (Fe) is an important element which is widespread in almost all types of environments. Fe minerals and Fe-complexes not only influence the environmental behavior of many toxic metals and compounds by binding and transformation to the Fe-complexes and Fe minerals which are characterized by high reactive surface areas and binding capacities, but also influence many other biogeochemical cycles (e.g. C, N, P, etc.). On one hand, Fe is a required element for nearly all organisms and it plays an important role especially in controlling the primary productions in the global oceans, on the other hand it was supposed to promote the preservation of organic matter by protection from microbial degradation.

The redox state of Fe and the presence of organic matter greatly influence the solubility of Fe in water. Under many environmental conditions, biotic processes are of particular importance for the cycling of the Fe redox state. Such biotic processes can be mediated via e.g. Fe(II)-oxidizing bacteria which are a group of microbial organisms that use oxygen, nitrate or light energy to catalyze Fe(II) oxidation. Although the chemical and microbial oxidation and reduction of pure Fe(II) and Fe(III) minerals has been studied in detail in the past, and a recent study reported that humic acid coprecipitation influences microbial Fe(III) reduction and secondary mineral formation (Shimizu et al., EST, 2013), there are still many knowledge gaps to fill when it comes to understanding the effect of organic matter complexation on the kinetics and the final products of microbial Fe(II) oxidation, for examples:

1. How does Fe(II)-OM complexation influence or even control the kinetics of microbial Fe(II) oxidation?

2. Do microbially oxidized Fe-OM complexes (Fe(III)-OM complexes and Fe(III)-mineral-OM-complexes) differ from chemically synthesized ones, e.g. with respect to the metal binding capacity and availability for Fe(III)-reducing bacteria?

Those questions will be approached in this PhD project using interdisciplinary techniques, including synthesis of Fe-complexes, microbial Fe(II) oxidation batch experiment and cell suspension experiment, and chemical analysis of aqueous and solid samples using X-ray absorption spectroscopy and Mössbauer spectroscopy.

For more details about the research conducted in the Borch group please click here.

Recent publications

Peng C, Sundman A, Bryce C, Catrouillet C, Borch T, Kappler A. 2018. Oxidation of Fe(II)–Organic Matter Complexes in the Presence of the Mixotrophic Nitrate-Reducing Fe(II)-Oxidizing Bacterium Acidovorax sp. BoFeN1. Environmental Science & Technology 52:5753-5763. doi: 10.1021/acs.est.8b00953.

Bryce, C. , Blackwell, N. , Schmidt, C. , Otte, J. , Huang, Y. , Kleindienst, S. , Tomaszewski, E. , Schad, M. , Warter, V. , Peng, C. , Byrne, J. and Kappler, A. 2018. Microbial anaerobic Fe(II) oxidation – ecology, mechanisms and environmental implications. Environmental Microbiology. doi:10.1111/1462-2920.14328

Previous Institutions

Master student, Max-Planck Institute for Marine Microbiology, Germany

Undergraduate Research Assistant, Center for Geomicrobiology, Aarhus University, Denmark

Bachelor student, China University of Geosciences, China

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