Fusibacter tunisiensis sp. nov., isolated from an anaerobic reactor used to treat olive-mill wastewater.

Strain BELH1(T), a novel mesophilic, anaerobic, halotolerant, rod-shaped bacterium, was isolated from a Tunisian wastewater digester. The cells of the strain are motile, measure 0.5×2-5 µm, and occur singly or in pairs. The strain reduced thiosulfate and elemental sulfur (but not sulfate or sulfite) into sulfide. It grew at 15-40 °C (optimum 30 °C), pH 5.8-8.4 (optimum 7) and with 0-10 % (w/v) NaCl (optimum 3.0 %). The genomic DNA G+C content of strain BELH1(T) was 38.2 mol% and the strain's predominant cellular fatty acids were C(14:0), a summed feature that contained iso-C(17:1) and/or anteiso-C(17:1) B, and C(16:0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain was most closely related to Fusibacter paucivorans (94.8 % sequence similarity). Based on phenotypic, phylogenetic and taxonomic characteristics, strain BELH1(T) represents a novel species of the genus Fusibacter, for which the name Fusibacter tunisiensis sp. nov. is proposed. The type strain is BELH1(T) ( = DSM 24436(T) = JCM 17481(T)).