Anaerosalibacter bizertensis gen. nov., sp. nov., a halotolerant bacterium isolated from sludge

Abstract

A strictly anaerobic, halotolerant and thermotolerant strain, designated C5BELT, was isolated in north Tunisia from storage tanks holding waste generated by the recycling of discarded motor oils. Cells of strain C5BELT were Gram-stain-positive, motile by laterally inserted flagella, straight, and spore-forming. Their two major fatty acids were iso-C15 : 0 and iso-C15 : 0 dimethyl acetal. Growth was observed at temperatures of 25–55 °C (optimum, 40 °C) and at pH 6–9 (optimum, pH 7.5). The salinity range for growth was 0–100 g l−1 NaCl (optimum, 5 g l−1). Yeast extract was required for growth. Strain C5BELT was heterotrophic, able to use glucose, pyruvate, succinate, yeast extract, bio-trypticase and peptone, but unable to grow on Casamino acids. Sulfate, thiosulfate, sulfite, elemental sulfur, fumarate, nitrate and nitrite were not reduced. The DNA G+C content of strain C5BELT was 31.1 mol%. 16S rRNA gene sequence analysis indicated that strain C5BELT was a member of the family Clostridiaceae , class Clostridia , phylum Firmicutes and was most closely related to Sporanaerobacter acetigenes Lup33T ( = DSM 13106T) (92.4 % similarity). On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain C5BELT can be classified as a novel species in a new genus, for which the name Anaerosalibacter bizertensis gen. nov., sp. nov. is proposed. The type strain of the type species is C5BELT ( = DSM 23801T = JCM 17239T).