Streptomyces zinciresistens sp. nov., a zinc-resistant actinomycete isolated from soil from a copper and zinc mine.

A filamentous actinomycete, designated strain CCNWNQ 0016(T), was isolated from soil from a zinc and copper mine in Shaanxi province, north-western China. A polyphasic taxonomic study was carried out to establish the status of strain CCNWNQ 0016(T). Chemical and morphological properties of the isolate were similar to those of species of the genus Streptomyces. Analysis of the almost complete 16S rRNA gene sequence placed strain CCNWNQ 0016(T) in the genus Streptomyces where it formed a distinct phyletic line with recognized species of this genus. The strain exhibited highest sequence similarities to Streptomyces niveoruber NBRC 15428(T) (98.8  %), Streptomyces griseoviridis NBRC 12874(T) (98.7  %) and Streptomyces aurantiogriseus NBRC 12842(T) (98.7  %). Furthermore, DNA-DNA hybridization studies between the novel isolate and these three strains showed relatedness values of 49.6 ± 0.6, 47.2 ± 0.9 and 46.9 ± 1.1  %, respectively. A number of phenotypic properties also enabled the isolate to be differentiated from related species of the genus Streptomyces. Therefore, it is proposed that strain CCNWNQ 0016(T) (=K42(T) =ACCC 41871(T) =HAMBI 3107(T)) should be classified as the type strain of a novel species in the genus Streptomyces, Streptomyces zinciresistens sp. nov. The maximum level of resistance to Zn²+ for strain CCNWNQ 0016(T) is 35 mM.