Isolation and Identification of a New Cold and Alkaline Tolerant Antibiotic Producing Streptomyces sp. From Soil

Abstract

Background: The ever-increasing resistance of microorganisms to pathogens and our inability to control infectious diseases indicate the importance of conducting research to find new antibiotics.<br><br>Objectives: The aim of the present research was to isolate, identify, and optimize a cold and pH resistant strain of Streptomyces with high antibiotic<br><br>production capability.<br><br>Methods: Soil samples were taken from the Telar forests of northern Iran, and the ACS52 strain was identified as a Streptomyces strain based on<br><br>the morphological, biochemical, and 16S rRNA gene analysis. Antibacterial features of the obtained strain were studied against a wide range of<br><br>Gram-positive and Gram-negative bacteria using the cross-culture method. In order to evaluate the antibacterial activity of culture product, two<br><br>seed cultures and three fermentation media were examined. Finally, the effects of various factors such as the type of carbon and nitrogen sources,<br><br>temperature, pH, and inoculation rate were investigated.<br><br>Results: Streptomyces sp. ACS52 is a cold-resistant alkalophilic bacterium strain with antibacterial activity against a broad spectrum of pathogenic<br><br>bacteria. The fermentation medium containing glycerol and ethyl acetate was suitable for the production and extraction of antibacterial compound,<br><br>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<br><br>10% were found to provide the optimal conditions for the antibacterial activity.<br><br>Conclusions: The crude extract of Streptomyces sp. ACS52 had high antibacterial activity against a wide spectrum of bacteria and could be of interest<br><br>due to its features such as ability to grow at low temperatures and alkaline pH levels.