MICROBIAL AND BOTANICAL STRATEGIES TO SUPPORT HUMAN DIGESTION AND GUT MICROBIOTA.

The interaction between diet, digestion, and the gut microbiota has become a central topic in nutrition and health research. Growing scientific and commercial interest has focused on functional foods and supplements that aim to support digestion, influence microbial communities, and provide health benefits without disrupting ecological balance. Developing products that are both effective and microbiome-compatible requires experimental models capable of capturing physiologically relevant conditions. This PhD project examined three categories of microbiome-related interventions: (1) spore-forming probiotics, (2) fungal enzyme supplements, and (3) botanical extracts. A central methodological approach was the application of standardized in vitro models, in particular the INFOGEST 2.0 protocol, which simulates the human gastrointestinal environment and provides reproducible digestion studies. These experiments were complemented by fecal microbiota incubations and targeted microbial cultures to assess viability, metabolic activity, and community responses. The overarching aim was to evaluate how specific products, including Heyndrickxia coagulans LMG S-24828, two fungal enzyme blends, and three botanical extracts, interact with gut-related processes. Emphasis was placed on safety, functional performance during digestion, and effects on selected commensal or probiotic strains. The findings contribute to the development of evidence-based strategies for improving digestive efficiency and maintaining microbial balance through microbiome-compatible supplements.