Chlorella Vulgaris Beij Research Articles

Биотестирование меламина с использованием многокомпонентной тест-системы

In recent decades, halogen-containing flame retardants have been gradually replaced by safer flame retardants, including nitrogen-containing compounds. However, their ecotoxicity is poorly studied. The ecotoxicity of melamine, a widely used nitrogen flame retardant, at concentrations equal to MPC in water (4 mg/L), 5 MPC (20 mg/L) and 10 MPC (40 mg/L) was assessed in this study using a complex of test organisms. The assessment of ecotoxicity using the dehydrogenase activity of Dietzia maris AM3 as a test microorganism revealed a stimulating effect of melamine at a concentration equivalent to the MPC; concentrations of 5 and 10 MPC inhibited the activity of dehydrogenases by 19.3% and 10.5%, respectively, indicating low toxicity. No toxic effects were observed on protococcal algae Chlorella vulgaris Beijer at any of the tested concentrations. The effect of melamine solutions on the mortality of crustaceans Daphnia magna Straus was noted only at a concentration of 10 MPC, and the mortality rate was 25%. Lemna growth inhibition test showed that melamine at concentrations equal to the MPC and 5 MPC had an inhibitory effect on the growth of Lemna minor L. It also caused a significant decrease (by 47–52%) in the total chlorophyll content in fronds when exposed to all studied concentrations of melamine.

Bioremediation of Basil Pesto Sauce-Manufactured Wastewater by the Microalgae Chlorella vulgaris Beij. and Scenedesmus sp.

Chlorella vulgaris and Scenedesmus sp. are commonly used in wastewater treatment due to their fast growth rates and ability to tolerate a range of environmental conditions. This study explored the cultivation of Chlorella vulgaris and Scenedesmus sp. using wastewater from the food industry, particularly from Italian basil pesto production tanks. The experiment involved different carbon dioxide concentrations and light conditions with a dilution rate of basil pesto wastewater at 1:2. Both microalgae strains were able to grow on pesto wastewater, and biomass characterization highlighted the influence of CO2 supply and light irradiation. The highest lipid storage was 79.3 ± 11.4 mg gdry biomass−1 and 75.5 ± 13.3 mg gdry biomass−1 for C. vulgaris and S. obliquus under red light (5% CO2 supply) and white light (0.04% CO2 supply), respectively. Protein storage was detected at 20.3 ± 1.0% and 24.8 ± 1.3% in C. vulgaris and S. obliquus biomasses under white light with a 5% CO2 and 0.04% CO2 supply, respectively. The removal of P, N, chemical oxygen demand, and biological oxygen demand resulted in 80–100%, 75–100%, 26–35%, and 0–20%, respectively.

Evaluation of the effect of a chlorella-based feed additive (<i>Chlorella vulgaris</i> Beijer) on the productivity of Loman Brown cross laying hens

The article presents the results of the study of the effect of the feed additive “Algobooster” based on chlorella (Chlorella vulgaris Beijer) on the productivity Loman Brown cross laying hens. The research was carried out in the conditions of a peasant farm located in the Leninsky district of the Moscow region. The experiment was carried out on three groups (15 birds in each group) of 200-day-old laying hens. In the first experimental group, Algobooster was given to each bird individually for 60 days at a dose of 2 ml per day, and in the second group – 4 ml per day. The control group received no additive. The results of the experiment showed that the introduction of the additive increased the egg production of laying hens: in the first experimental group, 30 additional eggs were obtained in comparison with the control, and in the second experimental group, 69 additional eggs were obtained. Thus, the use of the feed additive “Algobooster” in the dosage of 4 ml/head made it possible to achieve an economic effect by increasing the productivity of laying hens with an increase in profit of 42 rubles.

Optimization of chlorella vulgaris beijer cultivation process for bio hydrogen production

The technology for obtaining bio hydrogen from the micro algae Chlorella vulgaris is described, the stage of biomass accumulation is intensified, the effect of copper addition on the growth of Chlorella is studied, a new, optimized composition of the Tamiya medium was developed using mathematical modeling, the effect of the light spectrum, carbon dioxide content in the gas-air mixture and Chlorella cultivation was carried out in a continuous mode, which made it possible to greatly accelerate the accumulation of cells.Despite significant achievements in the field of biotechnology, hydrogen accumulation with the help of algae is still economically inexpedient, although the need for research in this direction is associated with the depletion of renewable energy sources, environmental problems and the increase in energy prices. Briefly, the main directions for the competitiveness of the technology are given; one of the vectors for solving this problem is obtaining bio-hydrogen during the metabolism of Chlorella, the cultivation of which is characterized by a number of advantages.The attractiveness of using Chlorella biomass for bio fuels is due to the high rate of biomass reproduction, ease of cultivation, and the use of carbon dioxide and small amounts of mineral salts, agricultural waste or sewage to ensure the growth of Chlorella. Chlorella vulgaris is able to increase the amount of its biomass dozens of times per day, while it takes months or even years for terrestrial plants.

Гидрохимический анализ и экотоксикологическая оценка качества вод реки Качи

Purpose: to conduct a hydrochemical analysis and give a comprehensive eco-toxicological assessment of the Kacha river water. Materials and methods. The content of chemical components in surface water was determined using titrimetric and photocolorimetric analyses. The degree of surface water pollution was calculated using a comprehensive assessment method on individual hydrochemical indicators, calculating the combinatorial water pollution index. Algotesting was carried out by measuring the optical density of the chlorella microalgae culture (Chlorella vulgaris Beijer). For phytotesting the seeds of dicotyledonous plants – cucumber (Cucumis sativus L.), soya bean (Glycine max (L.) Merr.) and monocotyledonous plants – common oats (Avena sativa L.) were used. Test parameters: seed germination and germination readiness, root and sprout length were analyzed. Results. According to the hydrochemical parameters of the Kacha river, the waters were classified as oligohaline, and according to the specific combinatorial index (S′ = 1.15) they were classified as slightly polluted ones of the second class. The values of the coefficient of complexity of water contamination rate during 2012–2018 were within 12 %. In 2023, the Kacha river water was defined as moderately hard water (7.4 mg-eq/cubic dm), while a decrease in the average water salinity (566.1 mg/cubic dm) and an improvement in its quality in terms of total iron (0.12 mg/cubic dm) were noted, which corresponded to the maximum permissible concentration for water bodies of municipal and amenity water use significance. The water algoeffect reached 57 %, and the phytoeffect – 87 %. Conclusions. The use of biological methods – algotesting and phytotesting – showed the presence of toxicants in the Kacha river water from the effluent to the mouth. The need for additional control of the river water quality during its use, including irrigation, was noted.

Комплексный экологический мониторинг негативного воздействия нефтесодержащих отходов в районах нефтяных месторождений как объекта экологического риска

In this paper peculiarities of negative impact of oil-containing waste to humans and biosphere and approaches to its estimation are considered. For the estimation of ecological risks of negative impact of oil-containing waste in areas of oil and gas fields it is suggested to take into account not only its toxicological and quantitative characteristics, but also the degradation of the territories of fields, potential recultivating capacity of fields, suitability of wastes for utilization etc. Negative ecological impact not only from operation but also from mothballed oil well should be investigated. Results of complex experimental researches of negative impact of oil-containing waste in regions of development and exploitation of oil and gas fields are described. In number of cases increased values of oil containing waste and heavy metals were determined in soil and in water environment. For oil wells of Mogutovskoye field acute toxicity of soil samples near to the wells and excess over maximum permissible concentrations of methane were determined. Results of monitoring of toxicological impact of oil containing waste in areas of different oil fields of Samara region and in oil treatment plants by using of biological testing methods have showed that a number of samples have enlarged toxicity and are causing acute toxic effect to the test-organisms – green algae Chlorella vulgaris Beijer and Scenedesmus quadricauda (Turpin) Brébisson, crustaceans Daphnia magna Straus. In number of cases increased values of oil products was observed. Thus, it was determined that negative impact of oil-containing waste in areas of oil fields is complex in nature and may cause significant ecological risks for air, water and soil. Results of work allow us to carry out more efficient and high quality monitoring of negative impact of oil-containing waste and estimation of ecological risks as well as to develop the measures for reduction of negative impact of oil-containing waste.

The effect of live chlorella suspension on the growth and development of grafted seedlings of Cabernet Sauvignon grapes

One of the ways to grow high-quality grafted grape seedlings is to use modern, environmentally friendly biologically active preparations. Today, such preparations include live chlorella suspension. Its use in grape nursery is a new and relevant technological method of growing planting material. The aim of the study was to show the effect of live chlorella suspension on the realization of the biological potential of grapevines, with the subsequent production of high-quality grafted grape seedlings. Field (recording of plant growth and development), laboratory (determination of quantitative and qualitative parameters of plants) and statistical (confirmation of the reliability of the results) research methods were used. The obtained results showed that for soaking rootstock and scion components it is advisable to use the strain Chlorella vulgaris Beijer, dilution 1:5, soaking should be carried out for 72 hours – rootstock components, 18 hours – scion components; for irrigation of grape garden plot it is advisable to use the strain Chlorella vulgaris Beijer. + Ge, dilution 1:5, it was carried out immediately after planting scions and three times during the growing season – in June, July, and August. The use of these strains of live chlorella suspension allowed obtaining a higher yield of standard seedlings from the garden plot, the plants had a well-developed root system and annual growth. Compared to the control, which was water, the total number of roots increased. Plants in these variants were also characterized by increased growth of the aboveground part. Indicators of total and mature growth, which characterize the overall development of grafted grape seedlings, were in the range of 687.1-773.2 cm3 (total growth volume), 337.9-386.6 cm3 (mature growth volume), while 730.1 and 362.6 cm3 , respectively, in the control. The records of the output of standard seedlings from the garden plot also showed the advantage of using a suspension of live chlorella (an increase of 19.0-21.0%) compared to water. The above technological methods allow obtaining high-quality grape seedling products and can be a promising alternative for more sustainable and environmentally friendly agricultural methods

Creation of a Photobioreactor for the Effective Growth of Chlorella and Study of the Effect of the Spectral Composition of Light on Its Biomass

Chlorella is a green eukaryotic microalga (Chlorella vulgaris). The microscopic cell is spherical, 2–10 μm in diameter. This microalga is one of the most important and promising for biomass production. Chlorella is cultivated in ponds or bioreactors with specified parameters that create favorable conditions for the growth of chlorella biomass. Each set of conditions creates the opportunities for changing the growth rate and output of individual products. Two strains of chlorella were the object of the study: 1 – chlorella with a thin cell wall (Chlorella vulgaris VKPM Al-24); 2 – chlorella with a thick cell wall (Chlorella vulgaris Beijer). The culture of chlorella was cultivated on modified Tamiya nutrient medium, at 24°C and 24-hour illumination. It was cultivated for 5 days in 1000 ml flasks, in opaque grow boxes with different lighting regimes. The control variant was grown in a light room with white fluorescent lamps with an intensity of 150 μmol/m2 s, and the culture was also grown in the dark. Laboratory experiments studying the effect of spectral composition of light on growth of two strains of chlorella culture allowed identifying some regularities: 1 – the largest increase in biomass is observed when using white fluorescent lamps (T = 2700K); 2 – in the case of using FR>R or FR=R, their inhibitory effect on the growth of the studied strains of chlorella was observed. In addition, similar results were obtained when determining the optical density of the cultures, suggesting that the chlorella strains studied are similarly responsive to the action of different spectral compositions of light. Analyzing the absorption spectrum, it should be noted that it has a continuous character. It has been experimentally established that the first maximum is located in the red region (660 to 690 nm) and the second in the blue region (430 to 450 nm). The minimum absorption is observed in the green light region (500 to 610 nm).

Biotesting for the objectivization of the hygienic evaluation of the surface and underground drinking water sources

Introduction. An algorithm for evaluating the hygienic safety of drinking water sources based on biotesting and studying sanitary and chemical indicators has been developed and tested. Materials and methods. The research methods included sanitary and chemical analysis of water samples, as well as biotesting methods using single-celled green alga Chlorella vulgaris Beijer and bull spermatozoa. Results. For experimental approbation of the developed algorithm for determining the hygienic safety of water based on a two-component system of express biotesting and measurement of sanitary and chemical indicators, 6 underground and 5 surface water sources were evaluated. The response of test objects indicating the presence of acute toxicity in water samples taken from surface and underground in many cases correlates with the excess of MPC for individual indicators identified by sanitary and chemical analysis. For two water samples, differences were found between the results of biotesting and sanitary-chemical analysis, and therefore it is necessary to conduct an extended toxicological and chemical assessment to identify the source of toxic effects. Limitations. The two-component test system cannot be used separately without sanitary and chemical analysis of water media. Conclusion. Biotesting can be an addition to sanitary and chemical analyses, showing the presence of toxic substances that are not in the list of mandatory indicators to be determined (according to MR 2.1.4.0176-20 (in Russian)).

Determining the algoflora of Dengizkol Lake and breeding promising species in laboratory conditions

This article found that 123 species and species of microscopic algae, belonging to 4 divisions, 9 classes, 19 orders, 25 families, 32 genera, are distributed in the algal flora of the Dengizkol reservoir. When analyzing microscopic algae of the Dengizkol natural reservoir in contour sections, it was found that the number of species is high in areas where water flows into the lake, and the number of species is low in areas remote from the inflow of water. In particular, 114 species of phytoplankton were found in the 1st circuit of the Dengizkol collector, 100 species in the 2nd contour of the reservoir of the Republic of Turkmenistan, 89 of them in the 3rd circuit of the ABMK-2 outlet canal. Chlorella vulgaris Beijer on 04” nutrient medium cells up to 45.1 million/ml, Scenedesmus obliquus (Turp.) Kütz. on the basis of experiments it was proved that the number of cells increased to 46.4 million/ml.

Оценка качества вод и донных отложений р. Каменка методом биотестирования

The Kamenka River, which flows through the territory of the Kokuisky oil field in Perm Krai as a result of intensive oil production and the intensive karstspread, has undergone serious man-made changes, which are manifested in the increased content of chlorides and petroleum products in the water. We assessed the ecological state of the ecosys-tem of the Kamenka river by biotesting, using Daphnia magnaStraus and Chlorella vulgarisBeijer as test objects. 8water samples and 11 sediment samples were examined.Most of the studied sampling points located at the source of the river are distinguished by the presence of pronounced oil manifestations, a sharp smell of hydrogen sulfide, white flakes and a bright blue color uncharacteristic of natural waters. The percentage deviations of the optical density values in the studied samples from the backgroundvalue, and the indicators of the toxic dilution factor(TDF) calculated from the control (distilled water) values are given. In all the studied water samples, the growth of chlorella algae (Chlorella vulgaris) is stimulated in comparison with the background, the highest percentage of deviation of the optical density value from the background is 112% in sample No 1, the lowest in sample No 5 is 26%. In two samples of bottom sediments: No1and No 4, the optical density values significantly exceed the background indicator by 121 and 27%, respectively. The remaining samples of bottom sediments were characterized by a decrease in optical density compared to the background from 17 to 55%. The TDFof the studied water samples ranges from 6 –in Iren river (background), up to 26 –at point No8, in samples of bottom sediments, the lowest value of TDFat the source of the river is 0.6, the highest is in sample No8. Comparison of the optical density of the studied samples with the control indicator (on distilled water) is considered unacceptable, since the results are misleading and contradict reality. To assess the toxicity of natural and man-made waters, we consider the use of background indicators to be promising. The results with the use of Daphnia magnaas a test object showed the insensitivity of this organism to the toxic effects of the studied samples. The maximum percentage of daphnia death in the test sample was 20% (8 surviving crustaceans out of 10), while the criterion of acute toxicity is the death of 50% or more daphnia.

Биотестирование реки Ивы и ее притоков методом измерения оптической плотности культуры водоросли хлорелла (Chlorella vulgaris Beijer)

The article givesan assessment of the quality of water in the Iva River (Perm), as well as its tributaries: Bolshaya Iva, Malaya Iva, Talazhanka and Uinka. The quality of water in the rivers was assessed using the method of toxicological control. The method is based on measuring the optical density of a culture of algae chlorella (Chlorella vulgarisBeijer). This biotesting method, due to its higher sensitivity relative to chemical methods of analysis, provides an opportunity for a comprehensive assessment of the content of pollutants in the aquatic environment. As a result of the work carried out, data were obtained on the change in the degree of toxicity of water from the sources of rivers to their mouths. A decrease in the optical density of chlorella and an increase in the degree of toxicity were observed for the waters of the Iva River and all its tributaries, except for the Uinka River. For the Iva River, a decrease in optical densityby 58% relative to the mouth was revealed, which may be associated with an increasingdegree of development of the river banks. The value of the toxicity dilution factor (TDF) for all rivers ranges from 3.95 to 32.43, which corresponds to a change in water quality from moderately toxic to highly toxic. The waters in the Bolshaya Iva River are the least toxic.

BIOTESTING METHODS FOR THE DETECTION OF DRUGS IN THE AQUATIC ENVIRONMENT

The article presents experimental data on the use of the biotesting method for the toxicological evaluation of tap water containing the antibiotic amoxicillin solution and the hormone 17-estradiol solution. Different test organisms differ in their sensitivity to toxicants. Therefore, a series of biotests using different test organisms from different systematic groups: daphnia (Daphnia magna Straus), infusoria (Paramecium caudatum), and algae (Chlorella vulgaris Beijer) were used to increase the accuracy of toxicity assessment of solutions. It was found that of the selected test cultures infusoria were the most sensitive to the solution with antibiotic and hormone. The effect of amoxicillin in the dose range from 0.000078 mg/L to 0.000000078 mg/L contributed to the toxic effect of the test cultures in the following sequence in descending order: infusoria daphnia = chlorella. In a toxicity study of water containing the hormone 17-estradiol in the dose range from 0.00001mg/L to 0.00000001 mg/L, the sensitivity of the test objects developed in the following chronology: infusoria chlorella. Daphnia (Daphnia magna Straus) were not at all susceptible to this class of drugs. Therefore, the proposed biotesting methods for the detection of drugs in the aquatic environment are a promising direction in assessing the toxicity of pharmpollutants in wastewater.

Isolation of Valuable Biological Substances from Microalgae Culture.

Methods for purifying, detecting, and characterizing protein concentrate, carbohydrates, lipids, and neutral fats from the microalgae were developed as a result of research. Microalgae were collected from natural sources (water, sand, soil of the Kaliningrad region, Russia). Microalgae were identified based on morphology and polymerase chain reaction as Chlorella vulgaris Beijer, Arthrospira platensis Gomont, Arthrospira platensis (Nordst.) Geitl., and Dunaliella salina Teod. The protein content in all microalgae samples was determined using a spectrophotometer. The extracts were dried by spray freeze drying. Pressure acid hydrolysis with 1% sulfuric acid was determined to be the most effective method for extracting carbohydrates from microalgae biomass samples. The highest yield of carbohydrates (more than 56%) was obtained from A. platensis samples. The addition of carbohydrates to the cultivation medium increased the accumulation of fatty acids in microalgae, especially in Chlorella. When carbohydrates were introduced to nutrient media, neutral lipids increased by 10.9%, triacylglycerides by 10.9%, fatty acids by 13.9%, polar lipids by 3.1%, unsaponifiable substances by 13.1%, chlorophyllides by 12.1%, other impurities by 8.9% on average for all microalgae. It was demonstrated that on average the content of myristic acid increased by 10.8%, palmitic acid by 10.4%, oleic acid by 10.0%, stearic acid by 10.1%, and linoleic acid by 5.7% in all microalgae samples with the addition of carbohydrates to nutrient media. It was established that microalgae samples contained valuable components (proteins, carbohydrates, lipids, fatty acids, minerals). Thereby the study of the composition of lipids and fatty acids in microalgae, as well as the influence of carbohydrates in the nutrient medium on lipid accumulation, is a promising direction for scientific research in the fields of physiology, biochemistry, biophysics, genetics, space biology and feed additive production.

The influence of the nutrient medium on the morphological features and cell viability of the microalgae <i>Chlorella vulgaris</i> Beijer

This paper discusses morphological features and the nature of the viability of the cell groups of the microalgae Chlorella vulgaris Beijer., growing in an artificial nutrient medium. It has been found that in the morphological aspect, the microalgae have a unicellular cell structure of rounded or ellipsoidal shapes with a diameter of cell structures from 2 to 10 microns. The structure of the chlorella cell is represented as a thin shell, in the cytoplasm of which the nucleus with a decorated chloroplast is immersed. The optimal parameters for the intensive growth of chlorella microalgae were temperature values in the range of +27+29C. In such temperature values, chlorella microalgae showed the best results in terms of cell growth rate and in the values of its viability index. At the same time, the culture of chlorella cells, having the ability to outstrip cell growth, is able to maintain its systematic variety for a long time. In addition, it has been found that chlorella cells have a pronounced phototropism, expressed in responses to a light pulse and the ability to purposefully move towards it in the form of phototaxis. Further observations showed that the majority of chlorella cells in the visible field of micrometry were about 46 microns in size with an average quantitative content of about 4,5 million microalgae cell structures in one milliliter of nutrient (culture) medium. The indicator of the optical density of the studied chlorella cell culture after 14 days of growth in the nutrient medium increased by the end of observations by a little more than 2 times, which indicates a sufficiently high value of the viability of the cell structures of the Chlorella vulgaris Beijer. microalgae culture.

Biosafety Analysis of Metabolites of Streptomyces tauricus Strain 19/97 M, Promising for the Production of Biological Products.

A biosafety study was carried out concerning the metabolites of Streptomyces tauricus strain 19/97 M. This strain is a promising producer of biological preparations and shows antagonistic properties against Fusarium fungi, which cause Fusarium wilt disease. The strain has a pronounced biological activity against conifers, cereals and legumes. The treatment of planting material reduces infections, increases germination and furthers plant productivity. Using metabolites, we understood the culture liquid separated by filtration after the cultivation of the strain. Animals of different taxonomic affiliations were used as test objects: (CBA × C57BI/6) F1 hybrid mice (Mus musculus) (warm-blooded organisms), Daphnia magna Straus (planktonic crustaceans) and the unicellular alga Chlorella vulgaris Beijer. In the study, we were guided by the test standards for acute oral toxicity and irritation to the skin, mucous membranes of the eyes and inhalation toxicity. The research results showed that the metabolites of the strain are not acutely toxic to organisms of different taxonomic levels. The metabolites of the strain do not have an irritating effect on the skin and mucous membranes of warm-blooded animals. Based on the studies carried out, metabolites can be used for creating a fungicidal biological preparation.

Monoraphidium sp. IBASU-A 574 (Selenastraceae, Chlorophyta) – перспективний продуцент біомаси для біоенергетики

he present studies were carried out to evaluate a potential biofuel application of the native strain Monoraphidium sp. IBASU-A 574 (Selenastraceae, Chlorophyta) adapted to the temperate zone climatic conditions. This strain was isolated from a small freshwater lake situated in Kyiv-city (Ukraine) by the reached culture method for obtaining desired strains of different species with high growth rate. It was identified based on its morphological characterization under light microscopy and 18S rRNA sequence analysis. Its culture’s growth, kinetic characteristics (specific growth rate and productivity) and biological peculiarities of the investigated strain were studied in comparison with the well-known biomass producer Chlorella vulgaris Beijer. CALU 157 under the same autotrophic cultivating conditions with using the modified Tamiya medium. It was established an active growth of Monoraphidium sp. IBASU-A 574 which was practically equal to the well-known producer and characterized by following parameters: a maximum cell density of 248 ∙ 10-6 cells ∙ mL-1, the specific growth rate of 1.4 days-1 and productivity of 72.5 ∙ 10-6 cells ∙ mL-1 ∙ days-1. The results of gas-liquid chromatography analysis showed that a fatty acid profile of this microalga included a complex of palmitic (C16: 0), oleic (C18: 1), linoleic (C18: 2) and linolenic (C18: 3) major fatty acids with suitable proportion for developing biodiesel feedstocks. Moreover, there was considerable variation in formation of its fatty acid composition depending on the stage of growth, that confirmed the necessity for such studies to determine both optimal time for growing algae and gaing maximum yield of target products. Thus, Monoraphidium sp. IBASU-A 574 was found to be the promising producer of biomass for bioenergetic industry due to obtained data of its growth characteristics and suitable fatty acid profile of lipids.

Оценка токсичности очищенных хозяйственно-бытовых сточных вод с целью их использования для орошения

The purpose of the research is to determine the toxicity of domestic wastewater after mechanical and biological treatment and the potential possibility of their use for irrigation. The toxicity of treated wastewater from wastewater treatment plants (Kadamovskiye WWTP) in Novocherkassk by the method of biotesting on different test objects – infusoria (Paramecium caudatum), green protococcal algae chlorella (Chlorella vulgaris Beijer), white mustard seeds (Sinapis alba) is evaluated. Laboratory studies were carried out in the accredited ecological and analytical laboratory of the Federal State Budgetary Institution «RosNIIPM». The results of biotesting at the chlorella test object showed that the treated household wastewater does not have a toxic impact. Biotesting at the infusoria test object determined only the toxic impact of wastewater after biological treatment. The length of the white mustard seed roots in wastewater after mechanical and biological treatment is above 120%, compared with the control, which proves the stimulant effect of these waters. So, according to the results of biotesting domestic wastewater after mechanical treatment from the Kadamovskiye WWTP in Novocherkassk can be potentially used for irrigation. According to the research results, wastewater after biological treatment «has a toxic impact», which causes their use for irrigation only after additional treatment.

Алелопатичний вплив мікроводоростей на пшеницю озиму

The results of the study of the allelopathic activity of the culture medium of two species of green and charophyte microalgae (Chlorella vulgaris Beijer. and Interfillum terricola (J.B.Petersen) Mikhailyuk et al.) to winter wheat (Triticum aestivum L.) in model pot experiments with the aim to discover of physiological mechanisms of allelopathy and finding effective and safe compounds with growth-promoting effects. The microalgae culture medium was applied in a rate of 1; 3 and 10 mL per a pot (250 mL) filled with sifted and sterilized gray podzolic soil, before sowing wheat seeds. Test plants were grown in a phytochamber under controlled conditions of light intensity, temperature and soil moisture. The number of germinated seeds was recorded from the 2nd to the 8th day after sowing. The vitality of winter wheat was evaluated at the end of the experiments using morphometric characteristics of growth (height of aboveground parts, leaf surface area, length of root system, number of lateral roots; dry matter mass of aboveground parts and roots) and content of photosynthetic pigments in leaves. At the end of the experiment, the indicators of electrical conductivity, redox potential, pH and content of nutrients in the soil were determined. The positive effect of microalgae on seed germination, growth and photosynthetic apparatus of T. aestivum plants was established. Culture medium of C. vulgaris showed a higher stimulating effect on seed germination and growth of wheat seedlings than I. terricola. The positive effect of microalgae on the photosynthetic activity of wheat and the content of organic carbon in the soil indicates the possibility of developing of biofertilizers based on them in order to improve the structural and functional organization of agroecosystems. The obtained results confirmed the prospects of C. vulgaris as a biofertilizer in crops. The allelopathic effect of I. terricola on vascular plants has been studied for the first time. The important role of indirect allelopathic mechanisms in the interactions between the studied species of microalgae and vascular plants has been established.

Influence of Carbohydrate Additives on the Growth Rate of Microalgae Biomass with an Increased Carbohydrate Content.

Our study focused on investigating the possibilities of controlling the accumulation of carbohydrates in certain microalgae species (Arthrospira platensis Gomont, Chlorella vulgaris Beijer, and Dunaliella salina Teod) to determine their potential in biofuel production (biohydrogen). It was found that after the introduction of carbohydrates (0.05 g⋅L−1) into the nutrient medium, the growth rate of the microalgae biomass increased, and the accumulation of carbohydrates reached 41.1%, 47.9%, and 31.7% for Arthrospira platensis, Chlorella vulgaris, and Dunaliella salina, respectively. Chlorella vulgaris had the highest total carbohydrate content (a mixture of glucose, fructose, sucrose, and maltose, 16.97%) among the studied microalgae, while for Arthrospira platensis and Dunaliella salina, the accumulation of total carbohydrates was 9.59% and 8.68%, respectively. Thus, the introduction of carbohydrates into the nutrient medium can stimulate their accumulation in the microalgae biomass, an application of biofuel production (biohydrogen).