Substrates for the isolation of bacteriocins: review

Background. Due to the increasing demand for fish products, the stock of wild fish is continuously being depleted. This leads to a high level of aquaculture development in the world. The high content of microorganisms in the water, including pathogenic ones, can negatively affect its quality and safety. Salmonella is a particular danger to aquaculture facilities. Hydrobionts can be carriers of this bacterium, which, when ingested, causes acute intestinal infection. This is especially important when eating raw products such as mussels, mollusks, and fresh fish. Currently, antibiotics are used to combat pathogenic microorganisms, the negative effects of which have been proven all over the world. In this regard, there is an urgent need to find effective solutions aimed at combating the negative impact of pathogenic microorganisms on aquaculture facilities. The use of bacteriocins, which cause the suppression of growth and death of pathogenic microorganisms, is considered promising. The effectiveness of probiotic drugs and bacteriocins can be improved by using beneficial bacterial strains present in the natural habitat of animals. This approach will make it possible to create specialized lines of probiotic drugs of different spectrum of action (antioxidant, antimutagenic, enzymatic, and others) that will promote the development of animal husbandry and minimize the use of antibiotics for the treatment of bacterial diseases. To create an effective feed additive based on bacteriocins in the fight against salmonella, it is necessary to select optimal conditions for the cultivation of new producing strains for maximum bacteriocin yield.

Purpose. Review and identification of potential culture media for growing bacterial strains present in the natural habitat of animals producing targeted bacteriocins.

Materials and methods. In the course of the study, a comparative analytical method was applied. The information base is based on the analysis of data presented in open scientific publications. Literary sources were searched in abstract and information databases, including eLibrary, the Russian State Library, ScienceDirect, ResearchGate, Google Scholar, National MedLine, the Wiley online Library and others. The following key terms were used as search queries: “Salmonella”, “bacteriocin”, “subiectum”, “bacterial iactatio”, “probiotic”, “prebiotic”, “salmonellosis” – both individually and in various combinations. No time limits were set for the search in order to cover the most representative array of publications.

Results. Yeast extract, peptone and glucose are universal additives in nutrient media for the isolation of bacteriocins. These components are found in almost all of the above-mentioned nutrient media, which indicates their likely high efficiency as sources of carbon and nitrogen. The use of molasses, soybean meal, wheat bran, and an enzymatic solution from lignocellulose waste proved to be worthy substrates not only in terms of the productivity of the bacteriocins themselves, but also in terms of the economic efficiency of the substrates. Wheat bran, lignocellulose waste, soybean meal, molasses are secondary raw materials. The use of secondary products and products of plant origin having prebiotic properties (for instance, a grain pile of wheat in the early stages of ripeness) as substrates for the isolation of bacteriocins is effective and is aimed at resource conservation.

Conclusion. The use of new bacterial strains isolated from natural habitats in order to produce bacteriocins in aquaculture will contribute to the development of animal husbandry and minimize the use of antibiotics for the treatment of bacterial diseases.