title: Anaerobic degradation of glycerol by desulfovibrio fructosovorans and D. carbinolicus and evidence for glycerol-dependent utilization of 1,2-propanediol
abstract: The degradation of glycerol by Desulfovibrio carbinolicus and Desulfovibrio fructosovorans was tested in pure culture with sulfate and in coculture with Methanospirillum hungatei. Desulfovibrio carbinolicus degraded glycerol into 3-hydroxypropionate with the formation of sulfide in pure culture and methane in the coculture. The maximum growth rates were 0.063 h-1 in pure culture and 0.014 h-1 in coculture (corresponding growth yields: 8.9 and 6.0 g dry weight/mol glycerol). With D. fructosovorans, the pathway of glycerol degradation depended upon the terminal electron acceptor. Acetate and sulfide were produced in the presence of sulfate, while 3-hydroxypropionate and methane were formed by the syntrophic association with M. hungatei. The maximum growth rates were 0.057 h-1 in pure culture and 0.020 h-1 in coculture (corresponding growth yields: 8.9 and 6.0 g dry weight/mol glycerol). In a medium containing both glycerol and 1,2-propanediol but no sulfate, D. carbinolicus and D. fructosovorans degraded both substrates. A drop in the concentration of 1,3-propanediol was observed, and propionate and n-propanol production was recorded. Putative biochemical pathways of 1,2-propanediol degradation by D. carbinolicus and D. fructosovorans indicated that the enzymes involved in this metabolism are present only when the strains are grown on a mixture of 1,2-propanediol and glycerol without sulfate.
authors.affiliation: Laboratoire de Microbiologie et Biotechnologie Appliquees a l'Environnement, Universite Cadi-Ayyad, Faculte des sciences & Techniques-Gueliz, B.P. 618, 40000 Marrakech, Maroc.
authors.initials: AI
authors.lastname: Qatibi
authors.initials: R
authors.lastname: Bennisse
authors.initials: M
authors.lastname: Jana
authors.initials: JL
authors.lastname: Garcia