Clostridium brassicae sp. nov., A Strictly Anaerobic Bacterium Isolated from High-Salt Industrial Wastewater

An obligately anaerobic, Gram-positive, rod-shaped bacterium (1.8-5.5 μm long, 0.6-0.9 μm wide), designated ZC22-4^T, was isolated from a pickle-processing wastewater treatment plant in Zhejiang province, P.R. China. Strain ZC22-4^T grows optimally at 37-40 °C and pH 7.0 in the presence of 1% (w/v) NaCl or 2.0% (w/v) sea salts. It contained C_16:0 (25.9%), C_14:0 (13.6%), and C_16:1 cis 9 (10.6%) as the dominant cellular fatty acid (> 10%). Polar lipids include phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), one unidentified phospholipid (PL), two unidentified glycolipids (GL), three unidentified amino phosphoglycolipids (APGL1-3), one unidentified aminoglycolipid (AGL), and one unidentified lipid (L). The genomic DNA G + C content of ZC22-4^T was 28.7%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ZC22-4^T belonged to the genus Clostridium and formed a clade with the most closely related Clostridium aestuarii HY-45-18^T (96.3%), Clostridium ganghwense HY-42-06^T (95.9%). The average nucleotide identity and DNA-DNA hybridization values among the genomes of strain ZC22-4^T and C. aestuarii HY-45-18^T and C. ganghwense HY-42-06^T were 75.7% and 77.3%, 21.7% and 23.0%, respectively. Based on the phenotypic, phylogenetic, and genetic data, strain ZC22-4^T represents a novel species in the Clostridium cluster I, for which the name Clostridium brassicae sp. nov. is proposed. The type strain is ZC22-4^T (= MCCC 1K07510T = JCM 35370^T).