Streptomyces 45 #

The Streptomyces strain 45#,which was isolated from soil can produce broad-spectrum antimicrobial substances with high activities. Analysis on these antimicrobial substances showed that they have notable antagonistic effects on phytopathogens as well as some bacteria, but unconspicuous on fungi comparably. A similarity of basic properties between Streptomyces strain 45# and Streptomyces nogalater was proved by a series of compare of the morphological, cultural characteristic, the physiological and biochemical properties. The results exhibited that the homology of 16S rDNA between these two strains reached 99%. A phylogenetic tree was constructed by comparing with some correlative published 16S rDNA sequences. According to the multi-classification principle and the phylogenetic analysis, the Streptomyces strain 45# should be nomenclatured as Streptomyces nogalater.To culture antibiotic overproducing strains, the study include using different physical and chemical factors to induce Streptomyces strain 45# to mutation. After original strain were mutagensised by UV combined LiCl and DES,5 high-yield strains were obtained. Using Oxford Plate Assay method, the antibiotic effect measured by the diameter of antibiotic circle of mutational strains including UV—10, UV—42, DES —17, DES-34, DES -41.At the same time, the effects of heat, pH and UV on the stability of the bioactive substance in the fermented broth were studied. The water solubility and ion character of the antibiotics were analysized by pH paper chromatography and thin-layer chromatography.The results showed that the strongly alkalescence , highly polarity antibiotics were stable to heat, pH and UV,and can be dissolved in organic solvent easily, but hard in water relatively.The physiological and biochemical characteristics of the high...