<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

<p><em>Bacillus subtilis</em> is the most studied bacterium from genus <em>Bacillus</em> and this microorganism is widespread in nature. <em>B. subtilis</em> is often found in fresh and seawater, in the rhizosphere, in the soil (especially contaminated with feces and manure). The large variety of strains are available in collections of microorganisms, but strains isolated from the rhizosphere of various plants are particularly interesting for science and practical use. At the same time, the morphological criterion (the form and other features of the colonies) is the main one in the identification of <em>B. subtilis</em> at the first stages of the study and allows to refuse of extraneous strains before use more expensive methods and materials. The article presents the description of the morphological diversity of <em>B. subtilis</em> strains that are used in agriculture. Typical R–colonies are characteristic of bacteria <em>B. subtilis</em>, and we established 2 morphologically diverse forms of these colonies in the studied strains.</p><p> </p>

Bifidobacteria commonly known as classic probiotics and today they gain huge popularity among supporters of wealth nutrition. These microorganisms colonize the intestines of a newborn baby through the mother's milk and joining him in a stable symbiosis, accompany the person throughout his life, exerting a beneficial effect on his health. These amazing microorganisms have great biotechnological potential and are widely used in medicine, veterinary medicine, food and pharmaceutical industries, agriculture and other fields of national economy. The beneficial effects of bifidobacteria on the host organism are vast and diverse. They are involved in enzymatic processes, perform vital minerals function (synthesis of vitamins B, K, folic and nicotinic acids), improve indices of protein, lipid, and mineral metabolism/ They also reinforce the hydrolysis of proteins, carbohydrates ferment, hydrolyzed fats, dissolve fiber, stimulate peristalsis, promote normal evacuation of the intestinal contents, promote the synthesis of essential aminoacids, better assimilation of calcium salts and vitamin D. Moreover, they have anti-anemic, anti-allergic action, and stimulate the lymphoid apparatus. The article presents a review of important technological and biological properties of bifidobacteria, which determine their biotechnological potential: culture-morphological, physiological, biochemical properties; habitat, taxonomy, nutrient medium, and conditions of incubation, antagonistic, antioxidant properties, acid resistance, probiotic properties, the practical application of bifidobacteria.

Представлены сравнительные данные антагонистической активности коллекционных штаммов L. acidophilus по отношению к тест-штаммам E. coli в зависимости от активной кислотности среды. Ключевые слова: антагонизм, Lactobacillus acidophilus, Echerichia coli, активная кислотность среды. The article presents the comparative data illustrating antagonistic activity of collection of strains of L. acidophilus in relation to the test strains of the E. coli depending on the active medium acidity.

The data on the study of the effectiveness of a new probiotic based on strains B. toyonensis B-13249 and B. pumilus B-13250 when growing shrimps are presented. The experiments were carried out on a private farm in Kazakhstan. The control group of shrimps, which did not receive the probiotic, completed the molting process on the 28th day of the experiment, and the experimental group – 10 days earlier. It was also found that the probiotic has a positive effect on the hydrochemistry of water in recirculating aquaculture system (RAS). The concentration of ammonium (NH3/NH4 +), nitrite (NO2) and nitrate (NO3-) nitrogen in the experimental group did not reach the limit value, in contrast to the control. Based on the obtained results, this probiotic can be recommended for greening aquaculture. The dosage of the probiotic when applied with brine shrimp as feed for shrimp is 1 g/100 g of dry cysts. The dosage of the probiotic when the RAS is added to the water is 5 g/600 l of circulating water once a week.

The ability of bacteria to quickly acquire antibiotic resistance and transfer it among different groups are created a global problem, since antibiotics are used not only in medicine, but also in agriculture. That is why to study of the antibiotic sensitivity of not only pathogenic bacteria, but also of beneficial microbes like Bacillus spp. is extremely important. Our results demonstrated that all the studied strains of the B. subtilis group were highly sensitive to cephalexin and enrofloxacin, while resistant to oxacillin. The B. subtilis B-5449 strain was the least resistant to the studied antibiotics, and the B. subtilis B-2896 strain was the most resistant.

Lactic acid bacteria are ubiquitous and occupy various ecological niches. These microorganisms are widely used in various industries due to their high and diverse enzymatic activity. Industry collections of microorganisms with technological valuable properties are created for the construction of bacterial sourdough compositions. The aim of our study was to study mesophilic Lactococci isolated from various ecological niches. Only 9 cultures (out of 100 strains of mesophilic Lactococci isolated from plants) can be attributed to promising for further use in industry. The proportion of strains with industrially valuable properties among animal lactobacilli was 19% higher. Therefore, objects of animal origin are the most appropriate source for isolation of mesophilic Lactococci strains, promising for use in the dairy industry.

This article aims to develop a probiotic for animals and aquaculture based on the Bacillus toyonensis B-13249 and Bacillus pumilus B-13250 strains. The selection of a nutrient medium was conducted for cultivating the inoculum of these microorganisms. Several bacteria fermentations of the Bacillus genus were performed in biological reactors with a capacity of 15 and 250 l. A technology for obtaining a finished probiotic for animals and aquaculture was developed. The results indicate that L-broth is the most optimal nutrient medium for cultivating the studied strains. The cultivation of B. toyonensis B-13249 and B. pumilus B-13250 strains in fermenters revealed that sporulation begins after 4–8 hours of fermentation. In contrast to the vegetative medium, the fermentative medium helped the bacilli develop a higher optical density (the maximum value in the B. pumilus strain – 2.400±0.149), pH value (maximum value in the B. toyonensis strain – 8.483±0.609) and titer (at least 1010 CFU/g). After 20–24 hours of incubation, both strains of bacilli in the fermenter, almost completely pass into endospores, which serve as a signal for the start of biomass centrifugation. This was indicated by the following: from a 15 l fermenter – 83.3±6.1 g of concentrate, from a 250 l fermenter – 499.8±51.4 g. The number of bacilli in a concentrated state was at least 1·1011 CFU/g for both strains. Obtaining a finished preparation required mixing bacterial concentrates with maltodextrin to a titer of at least 1·1010 CFU/g. The number of bacteria in the preparation checked every month during the year, recorded no value less than 1·1010 CFU/g. Thus, L-broth is most favorable for growing the mother culture of the B. toyonensis B-13249 and B. pumilus B-13250 strains, and fermentative nutrient medium – for the cultivation in fermenters. The expiry date of the bacilli-based biological preparation is at least 12 months, during which the drug’s polycomponence, color and consistency are preserved, in addition to the bacteria titer (at least 1·1010 CFU/g) and their viability.