Young researchers from the Max Planck Institute for Terrestrial Microbiology receive the Otto Hahn Medal

Wenhao Xu und Leonard Ernst are awarded for their outstanding doctoral theses in the fields of microbial biochemistry and geochemistry

The Max Planck Society is awarding the Otto Hahn Medal to two former doctoral students at the Max Planck Institute for Terrestrial Microbiology in Marburg this year. The award recognises the exceptional scientific achievements they made within the scope of their dissertations.

Wenhao Xu: How Bacteria Perceive Their Environment

In her doctoral thesis in Prof. Dr. Victor Sourjik's department, Wenhao Xu investigated how bacteria detect and process signals from their environment. To systematically map the specificity of bacterial receptors for certain ligands, she developed a strategy combining high-throughput cloning, AlphaFold modelling and ligand screening. This enabled her to identify specific binding partners for multiple previously uncharacterised domains of bacterial sensor proteins. The results provide important insights into how gut bacteria perceive nutrients and signalling molecules, and how they adapt to their host environment. In a further study, Wenhao Xu established a combinatorial screening method for the pathogen Pseudomonas aeruginosa. In the process, she discovered chemoeffectors relevant to the infection process that were previously unknown.

'I feel deeply honoured to receive the Otto Hahn Medal. I would like to sincerely thank the Sourjik Group and all my colleagues at the Max Planck Institute in Marburg for their continuous support and encouragement,' said Dr. Xu.

She completed her Master's degree in Microbiology at Shandong University in Jinan, China. Since October 2020, she has been pursuing her PhD at the Max Planck Institute for Terrestrial Microbiology in Marburg. She is currently an EIPOD-LinC Postdoctoral Fellow at EMBL Heidelberg.

Leonard Ernst: From Geochemistry to Biochemistry of Life

In his doctoral thesis at the MPI for Terrestrial Microbiology, Leonard Ernst addressed one of the most fundamental questions in biology: the transition from simple geochemistry to complex biochemistry. His research focused on iron-sulfur compounds and their role in methane formation, as well as the evolutionary development of nitrogen fixation, leading to the emergence of the highly complex enzyme nitrogenase. This enzyme enables the fixation of atmospheric nitrogen and its conversion into biomass. Working as part of Prof Dr Johannes Rebelein’s team, he demonstrated that the increase in the chemical complexity of these iron-sulfur systems is closely linked to an increase in catalytic efficiency, opening up entirely new reaction pathways. His findings are also relevant for assessing global methane cycles, as well as biomedical questions related to oxidative stress.

“Our research impressively demonstrates how iron-sulfur chemistry has evolved from non-enzymatic, slow and non-specific geochemistry towards enzymatic, faster and more specific biochemistry — all the way to the fixation of the nitrogen molecule, which is actually very unreactive,” says Dr. Ernst.

He studied biotechnology, geosciences and philosophy at Heidelberg University, earning his PhD at the MPI for Terrestrial Microbiology. He is currently a postdoctoral researcher in Chris Greening’s group at Monash University in Melbourne, Australia.

Since 1978, the Max Planck Society has awarded the Otto Hahn Medal annually to up to 30 young scientists in recognition of outstanding achievements during their doctoral studies. Named after the chemist and Nobel laureate Otto Hahn (1879–1968), the medal comes with a prize of 7,500 euros.