Foods and Raw Materials Foods and Raw Materials Foods and Raw Materials 2308-4057 2310-9599 103375 10.21603/2308-4057-2026-2-671 FQDYGY Research Article Research Article Research Article Effect of cultivation conditions on polysaccharide synthesis by Skeletonema pseudocostatum Effect of cultivation conditions on polysaccharide synthesis by Skeletonema pseudocostatum https://orcid.org/0000-0003-0603-7456 Dolganyuk Vyacheslav F. Dolganyuk Vyacheslav F. https://orcid.org/0000-0003-0442-5471 Kashirskikh Egor V. Kashirskikh Egor V. https://orcid.org/0000-0001-7910-8388 Sukhikh Stanislav A. Sukhikh Stanislav A. stas-asp@mail.ru Kremleva Olga E. Kremleva Olga E. https://orcid.org/0000-0003-4107-7277 Ulrikh Elena V. Ulrikh Elena V. Malkov Danil I. Malkov Danil I. https://orcid.org/0000-0002-4921-8997 Babich Olga O. Babich Olga O. Immanuel Kant Baltic Federal University Kaliningrad Россия Immanuel Kant Baltic Federal University Kaliningrad Russian Federation Kemerovo State University Россия Kemerovo State University Russian Federation Immanuel Kant Baltic Federal University Kaliningrad Россия Immanuel Kant Baltic Federal University Kaliningrad Russian Federation Immanuel Kant Baltic Federal University Kaliningrad Россия Immanuel Kant Baltic Federal University Kaliningrad Russian Federation Yanka Kupala State University of Grodno Grodno Беларусь Yanka Kupala State University of Grodno Grodno Belarus Kaliningrad State Technical University Kaliningrad Россия Kaliningrad State Technical University Kaliningrad Russian Federation Immanuel Kant Baltic Federal University Kaliningrad Россия Immanuel Kant Baltic Federal University Kaliningrad Russian Federation Immanuel Kant Baltic Federal University Kaliningrad Россия Immanuel Kant Baltic Federal University Kaliningrad Russian Federation 21 08 2025 21 08 2025 14 2 276 284 24 05 2024 06 05 2025 https://jfrm.ru/en/issues/23601/23734/

Microalgae are a source of biologically active substances, e.g., polysaccharides. Their commercial potential attracts a lot of scientific attention. This research featured the effect of various nutrient media on the biomass of the psychrophilic microalga Skeletonema pseudocostatum and its ability to synthesize polysaccharides. The Tamiya nutrient medium was used as the standard one. Its composition was improved to accelerate biomass cultivation. Optimization principles were based on the unconventional mathematical method for multidimensional modeling and involved the ANETR 21 software. The qualitative and quantitative assessment of microalgal polysaccharides relied on the anthrone sulfate method. The concentration of uronic acids was determined by the carbazole method while neutral sugars were studied by the resorcinol sulfate method in a microalgal suspension. The growth index of the S. pseudocostatum biomass was represented as a ratio of the maximal mass to the initial mass. The maximal growth index was achieved by adding to the standard Tamiya medium: 10.00 g/cm3 potassium nitrate (MgSO4×7H2O), 2.50 g/cm3 potassium dihydrogen phosphate, 1 cm3 Fe+ ethylenediaminetetraacetic acid (EDTA), and a mix of 4.29 g/cm3 boric acid and 0.9 g/cm3 manganese (II) chloride tetrahydrate (MnCl2×4H2O) in an amount of 1.00 cm3. The maximal polysaccharide biosynthesis was observed when the nutrient medium was modified as follows: 5.00 g/m3 potassium nitrate, 3.75 g/cm3 magnesium sulfate, 2.50 g/cm3 potassium dihydrogen phosphate, 1 mm3 solution of Fe+ ethylenediaminetetraacetic acid, and solution of 1.0 g/cm3 boric acid and 1.81 g/cm3 MnCl2×4H2O (1.00 mm3 each). The maximal accumulation of microalgal biomass was 2.88 ± 0.08 μg/100 mg dry solids; the maximal yield of polysaccharides was 3.16 ± 0.09 μg/100 mg dry solids. These results were obtained at 5°C. The yield of polysaccharides by S. pseudocostatum depended on such cultivation parameters as temperature and pH. At cultivation temperatures of 0, 5, and 10°C, the yield of polysaccharides reached 2.13 ± 0.06, 3.16 ± 0.09, and 2.04 ± 0.06 μg/100 mg dry solids, respectively. The yield of exopolysaccharides represented by uronic acids and neutral sugars was 106.3 ± 3.1 mg/g and 806.6 ± 24.0 mg/g, respectively. In this research, polysaccharides synthesized by S. pseudocostatum demonstrated good prospects for the food industry and sustainable organic agriculture.

Microalgae are a source of biologically active substances, e.g., polysaccharides. Their commercial potential attracts a lot of scientific attention. This research featured the effect of various nutrient media on the biomass of the psychrophilic microalga Skeletonema pseudocostatum and its ability to synthesize polysaccharides. The Tamiya nutrient medium was used as the standard one. Its composition was improved to accelerate biomass cultivation. Optimization principles were based on the unconventional mathematical method for multidimensional modeling and involved the ANETR 21 software. The qualitative and quantitative assessment of microalgal polysaccharides relied on the anthrone sulfate method. The concentration of uronic acids was determined by the carbazole method while neutral sugars were studied by the resorcinol sulfate method in a microalgal suspension. The growth index of the S. pseudocostatum biomass was represented as a ratio of the maximal mass to the initial mass. The maximal growth index was achieved by adding to the standard Tamiya medium: 10.00 g/cm3 potassium nitrate (MgSO4×7H2O), 2.50 g/cm3 potassium dihydrogen phosphate, 1 cm3 Fe+ ethylenediaminetetraacetic acid (EDTA), and a mix of 4.29 g/cm3 boric acid and 0.9 g/cm3 manganese (II) chloride tetrahydrate (MnCl2×4H2O) in an amount of 1.00 cm3. The maximal polysaccharide biosynthesis was observed when the nutrient medium was modified as follows: 5.00 g/m3 potassium nitrate, 3.75 g/cm3 magnesium sulfate, 2.50 g/cm3 potassium dihydrogen phosphate, 1 mm3 solution of Fe+ ethylenediaminetetraacetic acid, and solution of 1.0 g/cm3 boric acid and 1.81 g/cm3 MnCl2×4H2O (1.00 mm3 each). The maximal accumulation of microalgal biomass was 2.88 ± 0.08 μg/100 mg dry solids; the maximal yield of polysaccharides was 3.16 ± 0.09 μg/100 mg dry solids. These results were obtained at 5°C. The yield of polysaccharides by S. pseudocostatum depended on such cultivation parameters as temperature and pH. At cultivation temperatures of 0, 5, and 10°C, the yield of polysaccharides reached 2.13 ± 0.06, 3.16 ± 0.09, and 2.04 ± 0.06 μg/100 mg dry solids, respectively. The yield of exopolysaccharides represented by uronic acids and neutral sugars was 106.3 ± 3.1 mg/g and 806.6 ± 24.0 mg/g, respectively. In this research, polysaccharides synthesized by S. pseudocostatum demonstrated good prospects for the food industry and sustainable organic agriculture.

 Microalgae Skeletonema pseudocostatum polysaccharides optimization parameters nutrient medium Microalgae Skeletonema pseudocostatum polysaccharides optimization parameters nutrient medium The research was supported by the Ministry of Science and Higher Education of the Russian Federation as part of grant from the President of the Russian Federation, project no. MK-484.2022.1.4 (agreement no. 075-15-2022-393). The research was supported by the Ministry of Science and Higher Education of the Russian Federation as part of grant from the President of the Russian Federation, project no. MK-484.2022.1.4 (agreement no. 075-15-2022-393).

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