Identification Of A Rare Actinomycete Isolated From Mangrove

A polyphasic study was undertaken to establish the taxonomic position of strain 210417 isolated from mangrove soil. It is a combination of morphological, cultural characteristics observation, biochemical, physiological, chemical and molecular analysis.16S rRNA gene sequence analysis showed that the strain 210417 should be classified to the genus Nonomuraea, being most closely related to Nonomuraea coxensis JCM 13931T and Nonomuraea bangladeshensis JCM 13930T A mean DNA-DNA hybridization value of 56.5% and 36.9% was shown between strain 210417 and Nonomuraea coxensis JCM 13931T and Nonomuraea bangladeshensis JCM 13930T respectively. The G+C content of the genomic DNA was 72.0%.Highly branched substrate mycelia and aerial mycelia and sprial spore chains that are covered with rough sheath of strain 210417 was observed under light microscope and scanning electron microscope. Sporangia are not detected. Strain 210417 grew well on ISP-2(Yeast extract-malt agar), ISP-6(Peptone-yeast extract iron agar), ISP-7(Tyrosine agar) and DSMZ 54 (Glucose yeast extract)medium, weak on ISP-1(Tryptone-yeast extract agar), ISP-3(Oatmeal agar), MB(Modified Bennett’s agar), NA(Nutrient agar)and ISP-5(Glycerol-asparagine agar). Diffusible pigments are not produced.Growth temperature for strain 210417 ranges from 20℃to 37℃, with optimal growth occuring at 28℃. Growth pH ranges from 6.0 to 10.0, with an optimum at pH 7.2. Growth occurred in the presence of 0-4%NaCl (w/v). The strain could utilize L-arabinose, sucrose, D-xylose, D-mannose, D-fructose, L-rhamnose, D-raffinose as sole carbon sources, but not myo-inositol or cellobiose. It degrades casein tyrosine and gelatin, but does not degrade hypoxanthine, starch or xanthine. It is positive for aesculin hydrolysis, nitrate reduction, gelatinase, urease, arginine dihydrolase andβ-galactosidase production; negative for citrate lyase, lysine decarboxylase, ornithine decarboxylase or acetoin production.Meso-diaminopimelic acid was the diagnostic amino acid in the peptidoglycan. Whole cell-hydrolysates contained madurose, galactose, glucose, mannose and ribose. The main menaquinone of strain 210417 was MK-9(H4) (83%) and MK-9(H6) (10%). The principle fatty acids were iso-C16:0(38.7%) and 10-methyl C17:0 (12.6%). The polar lipids comprised phospholipid of unknown structure containing glucosamine, phosphatidylethanolamine and phosphatidylmethylethanolamine.It is, therefore, proposed that strain 210417T (=CGMCC 4.5598 T) represents a new species of the genus Nonomuraea, with the name of Nonomuraea wenchangensis sp.nov.