Nocardioides malaquae sp. nov., a novel actinobacterium isolated from sewage sludge of a fisheries processing factory.

A Gram-stain-positive, rod-shaped, strictly aerobic bacterial strain (Y6T) was isolated from a sewage sludge sample collected from a fisheries processing factory in Zhoushan, Zhejiang Province, PR China. The growth range of NaCl concentration was 0-6.0 % (w/v), with an optimum at 3.0 % (w/v). The temperature range for growth was 10-42 °C, with an optimum at 37 °C. The pH range for growth was pH 7.0-10.0, with an optimum at pH 9.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Y6T belonged to the genus Nocardioides and showed the highest sequence similarity of 97.8 % to Nocardioides jishulii dk3136T. The average nucleotide identity and in silico DNA-DNA hybridization values between strain Y6T and the reference strains were 76.9-81.2 % and 20.6-23.6 %, respectively. Chemotaxonomic analysis indicated that the sole respiratory quinone was MK-8(H4) and the predominant cellular fatty acids were iso-C16 : 0, 10-methyl-C17 : 0 and C18 : 1  ω9c. The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, four unidentified phospholipids, three unidentified aminolipids and five unidentified lipids. The peptidoglycan was ll-2,6-diaminopimelic acid. On the basis of the phenotypic, genotypic, phylogenetic and chemotaxonomic features, strain Y6T is considered to represent a novel species, for which the name Nocardioides malaquae sp. nov. is proposed. The type strain is Y6T (=KCTC 49504T=MCCC 1K04765T).