The producing organism was isolated from surface-sterilized tissue of Artemisia annua collected from Xishuangbanna, Yunnan province, China. The strain was identified as Streptomyces diastaticus subsp. ardesiacus according to the phylogenetic analysis. The genomic DNA of the strain was extracted and used as a template for PCR-mediated amplification of 16S ribosomal DNA. The amplicons were used for sequencing and the resulting 16S ribosomal DNA sequence was compared with those of the type strains of validly published species in the genus Streptomyces. Phylogenetic analysis showed that the strain shared a higher 16S ribosomal RNA gene sequence similarity with the closely related strain S. diastaticus subsp. ardesiacus NRRL B-1773T (accession number DQ026631). Meanwhile, the strain was examined for a number of key phenotypic properties known to be of value in streptomycete systematics, and the presence of l, l-diaminopimelic acid in the peptidoglycan together with its colonial characteristics supported its assignment to the genus Streptomyces.

A slant culture of the strain was inoculated into 500 ml Erlenmeyer flasks containing 100 ml of seed medium composed of yeast extract 0.4%, glucose 0.4%, malt extract 0.5%, multiple vitamins solution 0.35 ml l−1, pH 7.2 with no adjustment and cultured for 2 days at 28 °C on a rotary shaker at 220 r.p.m. This seed culture was used to inoculate the fermentation medium with 10% volume. The fermentation was carried out in 1000 ml Erlenmeyer flasks containing 300 ml of fermentation medium containing starch 2.4%, beef extract 0.3%, glucose 0.1%, yeast extract 0.5%, peptone 0.3%, CaCO3 0.4% at pH 7.0 with no adjustment and cultured for 7 days at 28 °C on a rotary shaker at 220 r.p.m. for upscale fermentation.

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