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A novel freshwater strain of Coccomyxa elongata (MZ–Ch64) was isolated from the Zaporizhia region, Ukraine. The identification was based on the phylogenetic analysis of SSU rDNA gene and ITS1–5.8S rDNA–ITS2 region and predicted secondary structure of the ITS2. Phylogenetic analysis placed this strain in the Coccomyxa group, within the class Trebouxiophyceae. The novel strain MZ–Ch64 formed a strongly supported lineage closest with C. elongata. The MZ–Ch64 strain differed from the morphological description of the species by the size of vegetative cells and absence of small mucilaginous caps at one end of the cell. A number of experiments with different concentrations of phosphate and nitrate were conducted to evaluate changes in the resulting fatty acid profiles and biomass productivity. The fatty acid profile and total fatty acids varied significantly under different nutrient deficiencies. The dominant fatty acid during cultivation on standard BBM medium, as well as in phosphorus‐depleted conditions, was oleic acid (to 48.0%–54.6% of total fatty acids). Absence of nitrogen alone, and absence of both nitrogen and phosphorus, led to an increase of palmitic acid (to 24.7%–25.6%), cis‐7‐hexadecenoic acid (to 14.8%) and α‐linolenic acid (to 9.1%–10.1%) in comparison with the control sample. The greatest variation was found for oleic acid (31.9%–54.6%). Thus, this strain can be considered as a potential producer of oleic acid or cis‐7‐hexadecenoic and α‐linolenic acids for biotechnological applications.

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The new species Nephrochlamys yushanlensis sp. nov. is described from a freshwater plankton sample. A comparison of morphology, 18S rDNA gene and ITS2 sequences, and fatty acid profiles showed that the novel strain represents a new lineage within the genus Nephrochlamys. For the first time with a member of the Selenastraceae, experiments with phosphate and nitrate deprivation were conducted to evaluate changes in biomass, lipid and triacylglycerol (TAGs) accumulation, and composition of fatty acids. Biomass dry weight under simultaneous nitrogen and phosphorus depletion was 1.73 g · L−1, which is significantly lower than the 2.41 g · L−1 observed in the control. All conditions of nutrient restriction significantly increased the lipid content in comparison with the control. The largest increase in the total lipid content, reaching 58.64% DW per cell at the end of cultivation, occurred with nitrogen deficiency. Significant increases in TAGs content (to 23.69% and 21.74%, respectively) occurred in phosphorus‐ and nitrogen‐depleted conditions in comparison to the control (16.90%). Oleic (49.8–64.1%), palmitic (21.1–22.7%), and linoleic (8.6–10.3%) acids were the dominant fatty acids when cultured on standard BBM medium, as well as with the shortage of nutrients. Phosphorus deprivation as well as absence of both nitrogen and phosphorus led to the appearance of FAMEs α‐linolenic (1.5–4.1%) and stearidonic (1.0–1.8%) acids. In general, FAME profiles revealed that the relative percentage of saturated and monounsaturated fatty acids increased (88.9% of total fatty acids) in nitrogen‐depletion conditions, suggesting this strain may be suitable for biodiesel production.

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The forest litter plays a significant role in forest ecosystems. The composition of the litter biota comprises micro- and mesofauna, and a great diversity of microorganisms, including unrecognized algae (eukaryotic representatives and Cyanoprokaryota). The aim of this work was to study the diversity of algae in the different types of forest litters and to clarify the relationship between the algae composition and the forest-forming tree species. Our results show that the pine forest litter is the most appropriate habitat for the development of green and yellow-green algae and that this litter type limits the variety of blue-green ones. The admixture of deciduous leaf litter to pine litter caused an increase in the species richness of blue-green algae and diatoms. The algae were unevenly distributed across the sub-horizons of pine litter. The highest species richness of algae was identified in the enzymatic sub-horizon of litter. The peculiarity of the composition of leaf litter algae was a significant variety of green, yellow-green and blue-green algae. The spatial organization of algae communities in the leaf litter was characterized by equal distribution of algae species in the litter-subhorizons.

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