Abstract:To improve the antibiotics production of Streptomyces qinlingensis sp. nov., protoplast regeneration combined with physical and chemical mutagenesis was used to selected high-yielding strains. The results showed that the antibacterial activities of strain R-72 from protoplast regeneration and NTG-1, H30-7 from protoplast mutagenesis against Bacillus subtilis were more than 20% higher than that of the original strain, and the heredity characters of those strains were stable in successive ten generations. The further bioassay experiments exhibited that the fungicidal and antibacterial activities of the fermentation broth from R-72, NTG-1 and H30-7 were remarkable increased comparing with that of the starting strain.