Background/aims: Human gut microbiota harbors numerous metabolic properties essential for the host's health. Increased intestinal transit time affects a part of the population and is notably observed with human aging, which also corresponds to modifications of the gut microbiota. Thus we tested the metabolic and compositional changes of a human gut microbiota induced by an increased transit time simulated in vitro.
View Article and Find Full Text PDFThe technical and ethical difficulties in studying the gut microbiota in vivo warrant the development and improvement of in vitro systems able to simulate and control the physicochemical factors of the gut biology. Moreover, the functional regionalization of this organ implies a model simulating these differences. Here we propose an improved and alternative three-stage continuous bioreactor called 3S-ECSIM (three-stage Environmental Control System for Intestinal Microbiota) to study the human large intestine.
View Article and Find Full Text PDFBackground: Optimization of industrial biomass directed processes requires the highest biomass yield as possible. Yet, some useful yeasts like Saccharomyces cerevisiae are subject to the Crabtree effect under glucose excess. This phenomenon can occur in large scale tank where heterogeneities in glucose concentrations exist.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
September 2011
Ethical and technical difficulties for in vivo studies on gut microbiotas argue for the development of alternative in vitro models: here, we describe a system simulating the proximal part of a human colon both nutritionally and physico-chemically with a procedure aimed to limit experimental variations over the time (Proximal Environmental Control System For Intestinal Microbiota--P-ECSIM). The continuous culture system P-ECSIM is first inoculated by a -20 °C glycerol stock established from the batch culture of a stool-inoculated medium. The anaerobic atmosphere is self-maintained by the gases produced in the ordinary metabolism of fermentations.
View Article and Find Full Text PDFThis work aimed to study the transition from respiratory to fermentative metabolism in Saccharomyces cerevisiae CEN.PK 113-7D and more specifically to evaluate the implication of the acetyl-coenzymeA-derived carbon transport from cytosol to mitochondria in the onset of the metabolic shift. The strategy consisted in introducing, during aerobic glucose-limited chemostat (D = 0.
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