Desulfoluna limicola sp. nov., a sulfate-reducing bacterium isolated from sediment of a brackish lake.

A novel sulfate-reducing bacterium, strain ASN36, was isolated from sediment of a brackish lake in Japan. Cells of strain ASN36 were not motile and rod-shaped, with length of 2.0-4.9 μm and width of 0.6-0.9 μm. Growth was observed at 5-35 °C with an optimum growth temperature of 25-30 °C. The pH range for growth was 6.6-8.8 with an optimum pH of 7.3. Major fatty acids were C ω7c and C. Under sulfate-reducing conditions, strain ASN36 utilized lactate, malate, pyruvate, butyrate, ethanol, butanol, glycerol, yeast extract and H/CO as growth substrate. Fermentative growth occurred on malate and pyruvate. The novel isolate used sulfate, sulfite and thiosulfate as electron acceptors. The genome of strain ASN36 is composed of a chromosome with length of 6.3 Mbp and G + C content of 55.1 mol%. Analyses of the 16S rRNA gene indicated that strain ASN36 is related to Desulfoluna species. Overall genome relatedness indices indicated that strain ASN36 does not belong to any existing species. In contrast to the closest relatives, strain ASN36 lacks genes for reductive dehalogenase required for organohalide respiration and does not use halogenated aromatics as electron acceptors. On the basis of its genomic and phenotypic properties, strain ASN36 (= DSM 111985 = JCM 39257) is proposed as the type strain of a new species, Desulfoluna limicola sp. nov.