DETERMINATION OF OPTIMUM CULTIVATION CONDITIONS FOR SYNTHESIS OF BACTERIOCINS WITH AND STRAINS AND THEIR STABILITY INVESTIGATION

Bacteriocins are substances of protein nature which have antimicrobial properties. Due to the wide spectrum of antagonistic activity which bacteriocins of some microorganisms have, they have the potential for being used as components of antibacterial drugs. Due to the widespread problem of antibiotic resistance of many bacterial strains that cause human diseases, the studying of bacteriocins is particularly relevant as they may be an alternative to antibiotics. Despite the popularity of researches devoted to the study of bacteriocins properties in recent years, many bacteriocins have not been discovered yet and this field of research is relevant. Thus the aim our research is determination of the optimum conditions for cultivation of Bacillus endopheticus and Bacillus licheniformis strains producing bacteriocins for increasing the efficiency of their synthesis, and studying the stability of bacteriocins. Optimum conditions for cultivation of Bacillus endopheticus and Bacillus licheniformis strains have been determined. They are the temperatures from 25 to 37 °C and the acidity of the medium from 6.5 to 8.0. The maximum growth of strains is observed at the temperature of 30 °C and pH 6.5. The influence of temperature and pH on bacteriocins sensitivity has been studied. Bacteriocins are proved to be stable at a neutral pH and a temperature not higher than 80 °C. Antagonistic activity of bacteriocins subjected to different temperatures and pH towards Escherichia coli strain has been determined using a disk diffusion method. The research results are valuable for the development of novel medicinal preparations based on bacteriocins.