isolation and identification of a new cold and alkaline tolerant antibiotic producing <i>streptomyces</i> sp. from soil

Background]the everincreasing resistance of microorganisms to pathogens and our inability to control infectious diseases indicate the importance of conducting research to find new antibiotics.[objectives]the aim of the present research was to isolate, identify, and optimize a cold and ph resistant strain of <i>streptomyces</i> with high antibiotic production capability.[methods]soil samples were taken from the telar forests of northern iran, and the acs52 strain was identified as a <i>streptomyces</i> strain based on the morphological, biochemical, and 16s rrna gene analysis. antibacterial features of the obtained strain were studied against a wide range of grampositive and gramnegative bacteria using the crossculture method. in order to evaluate the antibacterial activity of culture product, two seed cultures and three fermentation media were examined. finally, the effects of various factors such as the type of carbon and nitrogen sources, temperature, ph, and inoculation rate were investigated.[results]<i>streptomyces</i> sp. acs52 is a coldresistant alkalophilic bacterium strain with antibacterial activity against a broad spectrum of pathogenic bacteria. the fermentation medium containing glycerol and ethyl acetate was suitable for the production and extraction of antibacterial compound, respectively. glycerol and starch as the carbon source, soybean extract as the nitrogen source, temperature of 25°c, ph of 7, and inoculation rate of 10% were found to provide the optimal conditions for the antibacterial activity.[conclusions]the crude extract of <i>streptomyces</i> sp. acs52 had high antibacterial activity against a wide spectrum of bacteria and could be of interest due to its features such as ability to grow at low temperatures and alkaline ph levels.