Felix is an expert in host-microbiome research, metabolism and mucosal immunology. His research focuses on the molecular interactions between the host mucosal immune system, the microbiome and environmental factors such as nutrition, along with consequences for host fitness and their dysregulation in disease (infection, inflammatory bowel disease, cancer, malnutrition) mainly employing conditional in vivo models, gnotobiotics and Next-Generation-Sequencing-based methods such as 16S profiling, metagenomics or RNA sequencing. A particular aim of these efforts will be to develop nutritional or probiotic interventions as treatment options for inflammatory and metabolic diseases.

Felix published in leading journals including two highly-cited reviews in Nature Reviews Microbiology and an article in Cell Reports 2016 that received wide media coverage, e.g. BBC, Der Spiegel or Swedish Television. For example, he revealed how the microbiome programs the epithelial transcriptome (Genome Biology 2015), epigenome (Genome Medicine 2018) or  innate immunity (Mucosal Immunology 2016) and in collaborative effort elucidated TLR5 as a molecular factor encoding a neonatal window-of-opportunity shaping the microbiome with long-lasting physiological consequences (Nature 2018).

After studying biology (1,0) Felix received his PhD in cell biology in 2010 (summa cum laude) at Kiel University. From 2010 to 2015 Felix performed his postdoctoral training in the laboratory of Prof. Fredrik Bäckhed in Gothenburg, Sweden, and then joined the laboratory of Prof. Philip Rosenstiel at the Institute of Clinical Molecular Biology (IKMB) of Kiel University as senior postdoc and team leader “microbiome”. In 2020, Felix started the junior research group “functional host-microbiome analyses” at the IKMB and completed his habilitation in “Clinical Molecular Biology” at the medical faculty of Kiel University in January 2021. Since 2022, Felix is heading the Gnotobiology Platform, a core facility at the University Hospital Schleswig-Holstein (UKSH, Campus Kiel) for functional microbiome research (see GNOTOBIOTICS section for details).