Metabolic characterization and viable delivery of Akkermansia muciniphila for its future application

Kees van der Ark

Research output: Thesisinternal PhD, WU

Abstract

The gut harbors a complex ecosystem in which many bacteria, both beneficial and pathogens, thrive. The potential importance of A. muciniphila as a member of the intestinal microbiota comes from the fact that A. muciniphila is reversely correlated with several diseases and reduce the fat mass gain of mice fed a high fat diet. We describe the use of genome-scale metabolic models to further understand the genetic and metabolic potential of microbiota members, as well as potential phenotypes and influence on the host. We emphasize the importance of culturing bacteria and provide an outline in which GEMs are used to aid in the development of minimal culture media. The use of GEMs for the development of minimal media was applied for A. muciniphila. We found that the essential components of A. muciniphila medium are L-threonine and either N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine (GalNAc). The composition of the minimal medium was used to develop an animal component free medium. The addition of soy derived peptides increased the growth rate an yield, and the omission of animal components makes the cultured bacteria applicable in humans. We o analyzed the expression of the gene Amuc_1100, which was found to be involved in host signaling previously. There was no significant alteration in the expression of this genes, or genes in the associated gene cluster. In a subsequent experiment, we discovered that the anaerobic bacterium A. muciniphila is able to tolerate ambient . The addition of oxygen during growth increased the growth rate and yield, which was the result of cytochrome bd mediated oxygen reduction. To protect A. muciniphila during gastric passage, we encapsulated the cell in a water in oil in water double emulsion. We found a 100 fold higher survival of the encapsulated cells. We concluded that the double emulsion could be an effective matrix for the viable delivery of A. muciniphila. The final steps required for the application of A. muciniphila as therapeutic microbe are described shortly in the discussion, and are all within reach.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • de Vos, Willem, Promotor
  • Belzer, Clara, Co-promotor
Award date22 Jan 2018
Place of PublicationWageningen
Publisher
Print ISBNs9789463438254
DOIs
Publication statusPublished - 2018

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