AUTHOR=Elshaghabee Fouad M. F. , Bockelmann Wilhelm , Meske Diana , de Vrese Michael , Walte Hans-Georg , Schrezenmeir Juergen , Heller Knut J. 

TITLE=Ethanol Production by Selected Intestinal Microorganisms and Lactic Acid Bacteria Growing under Different Nutritional Conditions

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.00047

DOI=10.3389/fmicb.2016.00047

ISSN=1664-302X

ABSTRACT=<p>To gain some specific insight into the roles microorganisms might play in non-alcoholic fatty liver disease (NAFLD), some intestinal and lactic acid bacteria and one yeast (<italic>Anaerostipes caccae, Bacteroides thetaiotaomicron, Bifidobacterium longum, Enterococcus fecalis, Escherichia coli, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus plantarum, Weissella confusa, Saccharomyces cerevisiae</italic>) were characterized by high performance liquid chromatography for production of ethanol when grown on different carbohydrates: hexoses (glucose and fructose), pentoses (arabinose and ribose), disaccharides (lactose and lactulose), and inulin. Highest amounts of ethanol were produced by <italic>S. cerevisiae, L. fermentum</italic>, and <italic>W. confusa</italic> on glucose and by <italic>S. cerevisiae</italic> and <italic>W. confusa</italic> on fructose. Due to mannitol-dehydrogenase expressed in <italic>L. fermentum</italic>, ethanol production on fructose was significantly (<italic>P</italic> &lt; 0.05) reduced. Pyruvate and citrate, two potential electron acceptors for regeneration of NAD<sup>+</sup>/NADP<sup>+</sup>, drastically reduced ethanol production with acetate produced instead in <italic>L. fermentum</italic> grown on glucose and <italic>W. confusa</italic> grown on glucose and fructose, respectively. In fecal slurries prepared from feces of four overweight volunteers, ethanol was found to be produced upon addition of fructose. Addition of <italic>A. caccae, L. acidophilus, L. fermentum</italic>, as well as citrate and pyruvate, respectively, abolished ethanol production. However, addition of <italic>W. confusa</italic> resulted in significantly (<italic>P</italic> &lt; 0.05) increased production of ethanol. These results indicate that microorganisms like <italic>W. confusa</italic>, a hetero-fermentative, mannitol-dehydrogenase negative lactic acid bacterium, may promote NAFLD through ethanol produced from sugar fermentation, while other intestinal bacteria and homo- and hetero-fermentative but mannitol-dehydrogenase positive lactic acid bacteria may not promote NAFLD. Also, our studies indicate that dietary factors interfering with gastrointestinal microbiota and microbial metabolism may be important in preventing or promoting NAFLD.</p>