Microalgae in planktonic communities are the main producers of biomass in lake ecosystems; however, their stability is influenced by many environmental factors. This study aims to assess the ecological state of Lake Maybalyk, located in Astana (Kazakhstan), based on the study of the taxonomic diversity and structure of phytoplankton, zooplankton, and the physico-chemical properties of the water. From 2019 to 2021, samples were taken for phytoplankton analysis, hydrochemical analysis of the water, zooplankton, and saprobiological analysis of the algocenosis. The study also investigated the main morphometric parameters of the lake, as well as the composition of hydrobionts, such as zooplankton, zoobenthos, and ichthyofauna. The analysis of phytoplankton revealed the presence of 97 species and intraspecific taxa of microalgae, with 71 types of microalgal indicators indicating water saprobity. The planktonic algoflora in Lake Maybalyk is predominantly composed of diatoms (Bacillariophyta) and green algae (Chlorophyta), which play a vital role in oxygen production and the food chain within the reservoir. Based on the Pantle–Buck saprobity index (2.15–2.5), the water quality in Lake Maybalyk is classified as moderately polluted. The assessment of the water quality, considering the number and composition of indicator phytoplankton species, places Lake Maybalyk in class III (β-mesosaprobic). The hydrochemical indicators align with the hydrobiological indicators, confirming the water quality as class III. The trophic status of the reservoir, during the study period, can be described as average. The obtained data on both the hydrobiological and hydrochemical indicators correlate, suggesting satisfactory water quality and the ability of the reservoir to purify itself. This study contributes to the sustainable management of water resources, by providing essential data on the ecological state of Lake Maybalyk. The results underscore the importance of continuous biomonitoring, with microalgae as indicators of water quality, which is crucial for developing effective ecosystem conservation strategies.

Natural resources are in short supply, and the ecosystem is being damaged as a result of the overuse of fossil fuels. The creation of novel technology is greatly desired for investigating renewable and sustainable energy sources. Microorganisms have received a lot of interest recently for their potential to transform organic waste into sustainable energy and high-value goods. New exoelectrogens that can transmit electrons to electrodes and remove specific wastewater contaminants are expected to be studied. In this study, we examined three distinct samples (as determined by chemical oxygen demand and pH) that can be used as anolytes to generate power in single-chamber and double-chamber microbial fuel cells using graphite electrodes. Wastewater from poultry farms was studied as an exoelectrogenic anolyte for microbial fuel cell power generation. The study examined 10 different bacterial strains, numbered A1 through A10. Due to their highly anticipated capacity to metabolize organic/inorganic chemicals, the diverse range of microorganisms found in poultry wastewater inspired us to investigate the viability of generating electricity using microbial fuel cells. From the investigated bacterial strains, the highest voltage outputs were produced by strains A1 (Lysinibacillus sphaericus) and A2 (Bacillus cereus), respectively, at 402 mV and 350 mV. Among the 10 different bacterial strains, strain A6 generated the least amount of electricity, measuring 35.03 mV. Furthermore, a maximum power density of 16.16 1.02 mW/m² was achieved by the microbial fuel cell using strain A1, significantly outperforming the microbial fuel cell using a sterile medium. The strain A2 showed significant current and power densities of 35 1.12 mA/m² and 12.25 1.05 mW/m², respectively. Moreover, in the two representative strains, chemical oxygen demand removal and Coulombic efficiency were noted. Samples from the effluent anode chamber were taken in order to gauge the effectiveness of chemical oxygen demand removal. Wastewater had an initial chemical oxygen demand content of 350 mg/L on average. Strains A1 and A2 decomposed 94.28% and 91.71%, respectively, of the organic substrate, according to the chemical oxygen demand removal efficiency values after 72 h. Strains A1 and A2 had electron donor oxidation efficiencies for 72 h of 54.1% and 60.67%, respectively. The Coulombic efficiency increased as the chemical oxygen demand decreased, indicating greater microbial electroactivity. With representative strains A1 and A2, Coulombic efficiencies of 10% and 3.5%, respectively, were obtained in the microbial fuel cell. The findings of this study greatly advance the field as a viable source of power technology for alternative energy in the future, which is important given the depletion of natural resources.

The incorporation of water bodies into city surroundings is gaining popularity as metropolitan areas expand rapidly. Maintaining the ecological health of these lakes poses challenges for ecologists and local government officials, given the influence of human activity on hydrological and hydrochemical properties and the resident organisms. Lake Taldykol serves as an illustrative example of how substantial human involvement disrupts the natural equilibrium of water bodies. This disruption offers a valuable model for studying ecological succession patterns amid fluctuating hydrological conditions. The primary objective of this study was to understand how the decreasing water supply in Astana’s lake system affects the biodiversity of aquatic fauna. Studies on the fauna in the vicinity of Taldykol Lake were conducted from 2020 to 2022. The research classified species and quantitatively evaluated the fauna of the lake and its adjacent coasts. The quantitative data was then utilized to calculate the Shannon index for each unique biome. Results indicated a significant impact on the quantity and distribution of species due to a 65% reduction in the lake’s area. Several species emerged as particularly sensitive environmental indicators. Notably, the Shannon index decreased by 0.8 points (30%) from an initial value of 2.7 to 1.9 as the water area decreased by 2,800,000 square meters (65%), and the water volume decreased by 3,098,000 cubic meters (71%). This reduction highlights the ecological implications of the changing lake conditions on biodiversity and overall water quality.

Self-purification in surface waters involves many components of the aquatic ecosystem, among which aquatic microorganisms play an important role, which perform the function of primary oxidation or reduction of pollutants entering the reservoir. However, a number of chemicals that pollute lakes and rivers inhibit the activity of bacterioplankton. This leads to the fact that the ability of the reservoir to self-cleaning is sharply violated and its degradation occurs. The activity of the process of destruction of organic substances can be judged by the oxygen parameters in the water of rivers and lakes. The purpose of this work was to study the effect of general chemical pollution of substances in natural water bodies on the ability of self-purification due to microorganisms.To assess the ability of water bodies to self-purify, the R/BOD ratio was used. The functional activity of microorganisms in the samples was assessed by their ability to reduce the ratio of dissolved oxygen on the first day R1/BOD1 and on the fifth day R5/BOD5 in the presence of test pollutants: gasoline, surfactant and antibiotic.It was shown that the decrease in the self-cleaning ability of natural waters under the influence of various pollutants from bioorganic pollution both in the river and in the lake is of a general nature. In a comparative study of the degree of suppression of heterotrophic destruction in lake and river water for gasoline, Fairy detergent and antibiotic Ospamox 250 mg, the latter most sharply reduces the ability of water bodies to bioorganic destruction at a dilution of 1:999, and at a dilution of 1:99 completely destroys it.The second most inhibiting natural water self-purification agent is Fairy detergent. When diluted 1:9 and 1:99 Fairy reduces self-cleaning ability to zero on the fifth day.Gasoline is capable of suppressing self-purification only in relatively large quantities: 1:9 in relation to water.Key words: self-purification, bacterioplankton, dissolved oxygen, BOD, surfactant.

This review critically evaluates the integration of probiotics in poultry farming within Kazakhstan, set against the backdrop of increasing global demand for poultry meat. Probiotics are increasingly viewed as essential alternatives to antibiotics, which have long been used to enhance growth and prevent disease in poultry. The review identifies significant challenges within Kazakhstan, such as reliance on imported breeding stock, infrastructural constraints, and local disease profiles that complicate widespread probiotic adoption. However, it also highlights substantial opportunities driven by government initiatives like the "2018-2027 Program for the Development of Poultry Farming," which emphasize the reduction of antibiotic use and enhancement of food security. The development of local biopreparations, including "Polylactovit" and "Bentobak", underscores Kazakhstan's emerging role in agricultural biotechnology and its potential for self-sufficiency. The comparison with global practices reveals the need for Kazakhstan to adopt more advanced probiotic strains, aligning its poultry industry with international standards and enhancing its competitiveness. The findings suggest that leveraging government support, improving local production capabilities, and adopting global best practices could transform Kazakhstan into a regional leader in sustainable poultry farming.

Lake Taldykol is a water body that experiences significant anthropogenic impact, which is reflected in its hydrochemical and hydrobiological state. In this paper, a comprehensive analysis of water quality is carried out, including a study of the chemical composition, saprobity and structure of plankton communities. The aim of this work was to assess the species composition, abundance and biomass of phytoplankton and zooplankton of Lake Taldykol, as well as to determine possible changes in the structure of these communities under the influence of hydrological and environmental factors, in particular, under conditions of fluctuating water levels. The scientific significance of the work lies in the comprehensive study of anthropogenic impact on the reservoir and determination of its ability to self-purify. The practical significance lies in the possibility of using the obtained data to develop measures to protect and restore the lake ecosystem. The study revealed that the maximum permissible concentrations were exceeded for a number of pollutants, such as COD, suspended solids, phosphates, nitrites and iron, which indicates a high anthropogenic load. The dynamics of the number and biomass of phytoplankton and zooplankton indicate seasonal changes in the trophic level of the reservoir. Saprobic indices showed that the lake belongs to the β-mesosaprobic zone, but in spring and autumn there is a deterioration in water quality. Key words: phytoplankton, zooplankton, hydrochemistry, hydrobiocenosis.