Isolation and characterization of a desulforubidin-containing sulfate-reducing bacterium growing with glycolate

Abstract

Sulfate-dependent degradation of glycolate was studied with a new sulfate-reducing bacterium, strain PerGlyS, enriched and isolated from marine anoxic sediment. Cells were gram-negative, motile rods with a DNA G+C content of 56.2 + 0.2 tool%. Cytochromes of the b-and ctype and menaquinone-5 were detected. A sulfite reductase of the desulforubidin-type was identified by characteristic absorption maxima at 279, 396, 545, and 580 nm. The purified desulforubidin is a heteropolymer consisting of three subunits with molecular masses of 42.5 (o9, 38.5 ([3), and 13 kDa (7). Strain PerGlyS oxidized glycolate completely to CO2. Lactate, malate, and fumarate were oxidized incompletely, yielding more sulfide and less acetate than expected for typical incomplete oxidation of these substrates. Part of the acetate residues formed was oxidized through the CO-dehydrogenase pathway. The biochemistry of glycolate degradation was investigated in cell-free extracts. A membrane-bound glycolate dehydrogenase, but no glyoxylate-metabolizing enzyme activity was detected; the further degradation pathway is unclear.

Molecular characterization of sulfate‐reducing bacteria in a New England salt marsh

“…Some dsrAB sequences were related to members of the Desulfobulbaceae , another family of generally incompletely oxidizing SRB. The propionate‐oxidizing genus Desulforhopalus (Isaksen and Teske, 1996), and the glycolate oxidizer Desulfofustis glycolicus (Friedrich and Schink, 1995) fall within this family.…”

High overall diversity and dominance of microdiverse relationships in salt marsh sulphate‐reducing bacteria

“…Recent isolation of SRB capable of degrading diverse and previously unsuspected compounds has suggested that they are metabolized by SRB in the environment. For example, SRB capable of utilization of long‐chain fatty acids and alcohols, glycolate (Friedrich and Schink, 1995), hydrocarbons (Aeckersberg et al ., 1991) and aromatic compounds (Beller and Spormann, 1997; Phelps et al ., 1998; Galushko et al ., 1999; Harms et al ., 1999) have been described. High metabolic versatility is found particularly in the genera Desulfosarcina , Desulfococcus and Desulfobacterium (Widdel and Bak, 1992), and it is thus hypothesized that these play an important role in the marsh.…”

Glycolate as a metabolic substrate for the acetogen Moorella thermoacetica

“…To our knowledge, this is the first report of glycolate‐dependent growth by acetogenic or thermophilic, obligately anaerobic bacteria. To date, only two anaerobic glycolate‐utilizing mesophiles have been isolated and described: Desulfofustis glycolicus , a sulfate‐reducing bacterium (isolated from marine sediment), and Syntrophobotulus glycolicus , a fermentative bacterium (isolated from anoxic sewage sludge) [18–21]. In addition, mixed cultures of fermenting bacteria (derived from sludge) have been shown to be capable of converting glycolate to acetate, propionate, and CO 2 [22].…”

“…With D . glycolicus , the oxidation of glycolate to CO 2 is coupled to the reduction of sulfate to sulfide, and, in the process, energy is conserved via electron transport phosphorylation [20]. S .…”

“…glycolicus and S . glycolicus are different, both organisms appear to initially oxidize glycolate to glyoxylate [18, 20]. Whether glycolate metabolism by M .…”