Psychrophilic Microorganisms in Natural Sources of the Kemerovo Region: Isolation and Antimicrobial Properties

. Extreme psychrophiles still remain largely understudied. However, they can serve as biological components in drug production, as well as increase the shelf life of food products in food industry. Therefore, the properties of psychrophilic microorganisms are a relevant study object. The present research objective was to isolate new psychrophilic microorganisms in extreme low-temperature conditions of the caves of Gornaya Shoria and Salair (Kemerovo region) and study their antimicrobial properties. Study objects and methods. The research featured psychrophilic microorganisms isolated in the caves of the Kemerovo region. The sampling was performed in triplicate. The samples were placed in sterile paper. Antibiotic resistance was defined according to the area where the antibiotic plate suppressed bacterial growth. The cell suspension was placed in a Petri dish with an agar-based medium. The discs with antibiotics were put on the surface of the medium and incubated in a thermostat at 28°C for 24 h in order to describe the growth of the isolates. Results and discussion. The microbial communities of the Gavrilovskaya and Azasskaya caves produced seven isolates with different morphological characteristics. Isolates 1, 4, and 5 had pronounced suppressive properties at 2 ± 4°C. Isolates 1, 4, and 5 proved resistant to antibiotics. Isolate 1 exhibited high resistance (21–26) to Neomycin and Novogramon, medium resistance (17–22) to Ceparin, Kanamycin, Levomycin, Carbenicillin, and Streptomycin, and low (2–8) resistance to Benzylpenicillin and Clotrimazole. Isolate 1 had no antibiotic resistance to Ampicillin, Gentamicin, and Tetracycline. Isolate 4 showed high resistance (22–27) to Novogramon, medium resistance (10–22) to Tetracycline, Clotrimazole, Neomycin, Zeparin, Kanamycin, Levomycin, and Monomycin, and low resistance (2–8) to Ampicillin, Benzylpenicillin, Streptomycin, and Gentamicin. Isolate 4 demonstrated no antibiotic resistance to Carbenicillin and Polymyxin. Isolate 5 proved highly resistant (27–26) to Ceparin, Benzylpenicillin, Levomycetin, and Novogramon, and medium resistant (12–22) to Clotrimazole, Streptomycin, Neomycin, Gentamicin, Polymyxin, Carbenicillin, and Monomycin. Isolate 5 demonstrated no resistance to Ampicillin, Tetracycline, and Kanamycin. Conclusion. Psychrophiles can serve as microorganisms to create new biological products that suppress the development of diseases in plants. Psychrophiles proved an extremely promising research direction for cultivating and storing agricultural products.