PhD ceremony Mr. M.T. Khan: Novel physiological and metabolic insights into the beneficial gut microbe Faecalibacterium prausnitzii. From carbohydrates to current

PhD ceremony: Mr. M.T. Khan, 12.45 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Novel physiological and metabolic insights into the beneficial gut microbe Faecalibacterium prausnitziii. From carbohydrates to current

Promotor(s): prof. J.M. van Dijl

Faculty: Medical sciences

The trillions of micro-organisms residing in our gut play major roles in our health and wellbeing. Changes in this so-called gut microbiota are related with disease conditions, such as obesity, chronic gut inflammation and metabolic syndromes. One of the beneficial micro-organisms that disappears when patients develop an inflamed gut is Faecalibacterium prausnitziii, a highly oxygen-sensitive bacterium with important anti-inflammatory properties. Accordingly, it was suggested to apply F. prausnitzii as a probiotic for the treatment of such patients. The research described in this thesis therefore aimed at investigating the metabolic properties of F. prausnitziii. To this end an effective procedure for isolating F. prausnitziii from human feces was developed. Studies on isolated strains led to the discovery that they can actually thrive in moderately oxygenated environments, such as the gut mucosa, by consuming oxygen and at the same time forming a protective slime layer. Hereto, the bacteria use flavins and oxidized thiols that are abundantly present in the gut. This knowledge was then applied to develop formulations that allow the survival of F. prausnitziii for at least 24 hours at ambient air, where it would normally die within two minutes. Altogether, these findings pave the way for the biomedical exploitation of this and possibly other oxygen-sensitive gut microbes in the treatment of major disorders of the human gut. Intriguingly, the present studies suggest that F. prausnitziii can also be employed in a completely different way to the benefit of mankind, namely through power generation in microbial fuel cells.