Streptomyces polyasparticus sp. nov. isolated from cotton field soil by a medium applied with polyaspartic acid.

A novel Streptomyces strain (TRM66268-LWL) was isolated from cotton field soil by a medium supplied with polyaspartic acid (PASP) at Alar, Xinjiang, Northwest PR China, and characterized using a polyphasic taxonomic approach. The strain was found to degrade PASP, and grow well on the medium to take PASP as the sole carbon source. The TRM66268-LWL fermentation broth was applied to the surface of PASP, and there were pores on the surface of PASP after a period of time. The strain was observed to be Gram-stain-positive and to form greyish-white aerial mycelia that differentiated into straight spore chains with round spores. The whole-cell sugar pattern of TRM 66268-LWL consisted of ribose, mannose and arabinose, and the principal phospholipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, phosphatidylinositol and two undetermined polar lipids. The predominant menaquinones were MK-7, MK-7(H), MK-9(H), MK-10(H). The diagnostic cell wall amino acid was identified as LL-diaminopimelic acid. The G+C content of strain TRM66268-LWL was 70.11 mol%. The average nucleotide identity value between strain TRM66268-LWL and the phylogenetically related strain Streptomyces indicus IH32-1 was calculated to be 85.49%. The digital DNA-DNA hybridization value between them was 30.40%. A multilocus sequence analysis of five house-keeping genes (atpD, gyrB, rpoB, recA and trpB) also illustrated that strain TRM66268-LWL should be assigned to the genus Streptomyces. On the basis of evidence from polyphasic study, strain TRM66268-LWL is designated as representing a novel species of the genus Streptomyces, for which the name Streptomyces polyasparticus sp. nov. is proposed. The type strain is TRM66268-LWL (CCTCC AA 2020003 = LMG32106).