This doctoral thesis, directed by Manuel Porcar, is the result of the collaboration of the Institute of Integrative Systems Biology I2SysBio (Universitat de València-CSIC) and the Robert Boyle Institute (Jena, Germany). Abendroth has studied various aspects of the anaerobic digestion of biomass, a previous step for the generation of biogas, an alternative fuel. The results of the thesis have been published in journals such as "Biotechnology for biofuels" or "Waste management and research". The thesis was defended on February 23, 2018 and received the rating of Outstanding.

The anaerobic digestion of biomass, such as agricultural or water purification waste, is a preliminary step in the generation of renewable energy such as biogas (methane). In recent years, more than 20,000 biogas plants have been established in Germany. The processes of biomass digestion, formation of volatile organic acids and, finally, methane, are carried out by complex microbial communities, made up of very diverse populations of bacteria and archaea. During his research, Abendroth has carried out the largest analysis of the predominant bacterial communities in nine biogas production plants in Thuringia. Likewise, it has introduced metagenomics and metaproteomics analyzes to have a more precise knowledge of the taxonomic diversity of these communities, their metabolic functions and the dynamics of the digestion process. Abendroth's thesis also provides applied studies such as the production of electricity from the heat given off by microbial cultures.

Christian Abendroth arrived at the Universitat de València in the summer of 2011 as an internship student of the Erasmus program in the Biotechnology and Synthetic Biology laboratory directed by Manuel Porcar at the Cavanilles Institute of Biodiversity and Evolutionary Biology. After graduating, he obtained a project from the German Ministry of Economy and Technology to develop his doctoral thesis between the Robert Boyle Institute in Jena and the Cavanilles Institute. With the creation of I²SysBio, Dr. Porcar's group has been integrated into the Applied Systems Biology and Synthetic Biology Program, where Abendroth has completed his thesis.

The panel, which rated the thesis "Outstanding", was made up of Marta Tortajada (head of the Microbial Biotechnology Department of the biotechnology company Biópolis SL), Michael Klocke (Leibniz Institute of Agricultural Engineering and Bioeconomy) and Juli Peretó (professor of the Department of Biochemistry and Molecular Biology of the University of Valencia and vice director of I²SysBio).

Photo by Kristie Tanner: C. Abendroth (left) and M. Porcar