Streptomyces beihaiensis sp. nov., a chitin-degrading actinobacterium, isolated from shrimp pond soil

Abstract

A Gram-stain-positive actinobacterium, designated strain GXMU-J5T, was isolated from a sample of shrimp pond soil collected in Tieshangang Saltern, Beihai, PR China. The morphological, chemotaxonomic and phylogenetic characteristics were consistent with its classification in the genus Streptomyces . The organism formed an extensively branched substrate mycelium, with abundant aerial hyphae that differentiated into spores. Phylogenetic analysis of 16S rRNA gene sequences showed that strain GXMU-J5T was most related to Streptomyces kunmingensis DSM 41681T (similarity 97.74 %) and Streptomyces endophyticus YIM 65594T (similarity 96.80 %). However, the values of digital DNA–DNA hybridization, average nucleotide identity and evolutionary distance of multilocus sequence analysis between strain GXMU-J5T and its closest relatives indicated that it represented a distinct species. Strain GXMU-J5T contained ll-diaminopimelic acid and the major whole-cell hydrolysates were xylose and galactose. The predominant menaquinones of strain GXMU-J5T were revealed as MK-9(H4), MK-9(H6) and MK-9(H8). The polar lipids consisted of diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol mannosides and phospholipids of unknown structure containing glucosamine. The predominant cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, iso-C17 : 0 and anteiso-C17 : 0. The whole genome size of strain GXMU-J5T was 6.79 Mbp with a 71.39 mol% G+C content. Genomic analysis indicated that strain GXMU-J5T had the potential to degrade chitin. On the basis of these genotypic and phenotypic data, it is supported that strain GXMU-J5T represents a novel species of the genus Streptomyces , for which the name Streptomyces beihaiensis sp. nov. is proposed. The type strain is strain GXMU-J5T (=MCCC 1K08064T=JCM 35629T).

Streptomyces fuscus sp. nov., a brown-black pigment producing actinomycete isolated from dry mudflat sand

“…Soil samples were collected from the dry mudflat sand in Beihai, Guangxi, PR China (latitude: 21.6243290 N; longitude: 108.9088834 E), and were sealed and stored at 4 °C after sampling. Strain GXMU-J15 T was isolated by dilution coating on chitin-screening agar medium [9] (g l −1 ; KH 2 PO 4 0.3, K 2 HPO 4 0.7, FeSO 4 ·2H 2 O 0.01, MgSO 4 ·7H 2 O 0.5, colloidal chitin 2, agar powder 20; pH 7.2) and later purified by scratching on lysogeny broth agar medium (LB; Difco). The purified culture of strain GXMU-J15 T was then inoculated onto yeast extract–malt extract agar (International Streptomyces Project, ISP 2) medium [10] and the spore filaments were collected after 21 days of incubation at 28 °C and preserved at −20 and −80 °C after the addition of 30 % (v/v) glycerol, respectively.…”

“…for 10 min). The obtained organisms were further lyophilized for subsequent chemical composition analysis [9]. The analyses of the diagnostic diamino acid in the cell-wall hydrolysates and the whole-cell sugars components were performed by TLC using standard methods described previously [22,23].…”

“…Further blast alignment and molecular phylogenetic tree analysis of the 16S rRNA gene sequences of these strains indicated that they may be new Streptomyces species. A novel species of Streptomyces from Beihai with chitin hydrolytic activity had been reported by the author’s research group, and strain GXMU-J5 T had been identified as a potential type strain of a new Streptomyces species by a polyphasic classification [9]. In this study, 16S rRNA gene sequence analysis of strain GXMU-J15 T , isolated from dry mudflat sand sampled in Beihai, Guangxi, showed the highest 16S rRNA gene similarity to Streptomyces lusitanus CGMCC 4.1745 T and Streptomyces thermocarboxydus CGMCC 4.1883 T of 99.1 and 98.8% respectively.…”