Desulfovibrio aminophilus sp. nov., a novel amino acid degrading and sulfate reducing bacterium from an anaerobic dairy wastewater lagoon

A mesophilic strain of sulfate-reducing bacterium, designated ALA-3(T) (T = type strain), was isolated from an anaerobic lagoon of a dairy wastewater treatment plant. The curved, Gram-negative, nonsporeforming cells (0.2 x 3.0-4.0 pm) existed singly or in chains, and were motile by single polar flagella. Optimum growth occurred at 35°C and pH 7.5 on a medium containing lactate and sulfate. Thiosulfate or sulfite but not elemental sulfur, nitrate, or fumarate could also replace sulfate as an electron acceptor. Formate, alanine, aspartate, leucine, isoleucine, valine, and methionine, H₂/CO₂ and ethanol also served as electron donors with sulfate as an electron acceptor. Pyruvate, casamino acids, peptone, serine, glycine, cysteine and threonine were fermented. Sulfite and thiosulfate were disproportionated to sulfate and sulfide. The G+C content of the DNA was 66 mol % G+C. Phylogenetic analysis revealed that Desulfovibrio africanus was the nearest relative (similarity of 89%). Strain ALA-3(T) is physiologically and phylogenetically different from other Desulfovibrio species, and is designated Desulfovibrio aminophilus sp. nov. (DSM 12254).