Microalgae are a valuable natural resource for a variety of value-added products. The growth of microalgae is determined by the impact of many factors, but, from the point of view of the implementation of autotrophic growth, light is of primary importance. This work presents an overview of the influence of light conditions on the growth of microalgae, the content of lipids, carotenoids, and the composition of fatty acids in their biomass, taking into account parameters such as the intensity, duration of lighting, and use of rays of different spectral composition. The optimal light intensity for the growth of microalgae lies in the following range: 26−400 µmol photons m⁻² s⁻¹. An increase in light intensity leads to an activation of lipid synthesis. For maximum lipid productivity, various microalgae species and strains need lighting of different intensities: from 60 to 700 µmol photons m⁻² s⁻¹. Strong light preferentially increases the triacylglyceride content. The intensity of lighting has a regulating effect on the synthesis of fatty acids, carotenoids, including β-carotene, lutein and astaxanthin. In intense lighting conditions, saturated fatty acids usually accumulate, as well as monounsaturated ones, and the number of polyunsaturated fatty acids decreases. Red as well as blue LED lighting improves the biomass productivity of microalgae of various taxonomic groups. Changing the duration of the photoperiod, the use of pulsed light can stimulate microalgae growth, the production of lipids, and carotenoids. The simultaneous use of light and other stresses contributes to a stronger effect on the productivity of algae.

Microalgae, capable of accumulating large amounts of lipids, are of great value for biodiesel production. The high cost of such production stimulates the search for cultivation conditions that ensure their highest productivity. Reducing the content of nitrogen and phosphorus in the culture medium is widely used to change the content and productivity of lipids in microalgae. Achieving the right balance between maximum growth and maximum lipid content and productivity is the primary goal of many experimental works to ensure cost-effective biodiesel production from microalgae. The content of nitrogen and phosphorus in nutrient media for algal cultivation after converted to nitrogen (-N) and phosphorus (-P) lies in an extensive range: from 0.007 g L^− 1 to 0.417 g L^− 1 and from 0.0003 g L^− 1 to 0.227 g L^− 1 and N:P ratio from 0.12:1 to 823.33:1. When studying nutritional stress in microalgae, no single approach is used to determine the experimental concentrations of nitrogen and phosphorus. This precludes the possibility of correct interpretation of the data and may lead to erroneous conclusions. This work results from the systematisation of information on using nitrogen and phosphorus restriction to increase the lipid productivity of microalgae of different taxonomic and ecological groups to identify future research directions. The results of 301 experiments were included in the analysis using the principal components method. The investigation considered various divisions and classes: Cyanobacteria, Rhodophyta, Dinophyta, Haptophyta, Cryptophyta, Heterokontophyta/Ochrophyta (Bacillariophyceae, Eustigmatophyceae, Xanthophyceae), Chlorophyta, and also the ratio N:P, the time of the experiment, the light intensity during cultivation. Based on the concentrations of nitrogen and phosphorus existing in various nutrient media, a general scheme for designating the supply of nutrient media for nitrogen (as NO₃⁻ or NH₄+, N g L^− 1) and phosphorus (as РO₄⁻, P g L^− 1) has been proposed: replete -N (˃0.4 g L^− 1), moderate -N (0.4–0.2), moderate N-limitation (0.19–0.1), strong N-limitation (˂0.1), without nitrogen (0), replete -Р (˃0.2), moderate -P (0.2–0.02), moderate P-limitation (0.019–0.01), strong P-limitation (˂0.01), without phosphorus (0).

A novel freshwater strain of Coelastrella multistriata MZ–Ch23 was discovered in Tula region, Russia. The identification is based on morphological features, phylogenetic analysis of SSU rDNA gene and ITS1–5.8S rDNA–ITS2 region and predicted secondary structure of the ITS2. Phylogenetic analysis places the novel strain in the “core” Coelastrella clade within the Chlorophyceae. This is the first record of Coelastrella multistriata in the algal flora of Russia. Cultivation experiments were carried out to evaluate growth dynamics of the newly identified strain and the impact of nitrogen and/or phosphorus depletion on the fatty acid profiles and lipid productivity. On the fully supplemented Bold’s basal medium and under phosphorus-depleted conditions as well, the fatty acid profiles were dominated by α-linolenic acid (29.4–38.1% of total fatty acids). Depletion of either nitrogen or both nitrogen and phosphorus was associated with increased content of oleic acid (32.9–33.7%) and linoleic acid (11.9%). Prolongation of the growth to two months (instead of 25 days) resulted in increased content and diversity of very long-chain fatty acids including saturated species. The total very long-chain fatty acid content of 9.99% achieved in these experiments was 1.9–12.3-fold higher than in stress experiments. The highest variation was observed for oleic acid (3.4–33.7%). The novel strain showed the ability to accumulate lipids in amounts up to 639.8 mg L⁻¹ under nitrogen and phosphorus starvation, which exceeds the previously obtained values for most Coelastrella strains. Thus, the newly identified MZ–Ch23 strain can be considered as a potential producer of omega-3 fatty acids on fully supplemented Bold’s basal medium or as a source of biomass with high content of saturated and monounsaturated fatty acids after nitrogen and phosphorus starvation.

The Altai Mountains of central Asia are biologically rich and comprise a wide diversity of ecosystems and lineages, including numerous endemic vascular plant species. Here we provide an updated checklist of the endemic vascular flora of the Altai Mountains with more taxa and higher geographic resolution than previously reported, as well as first molecular data and specimen images for many of these species. This flora is now known to contain 321 endemic species distributed in 34 families, many of which are narrowly restricted to one subregion of the Altai. The Fabaceae has given rise to the most endemic species in the Altai (74 spp.), and most of this diversity is found in the large and ecologically important genera Astragalus and Oxytropis. Approximately 60% of the endemic flora was imaged and successfully barcoded with at least one of three common DNA barcoding loci, and a phylogenetic tree based upon these loci is also presented to display the evolutionary breadth of endemism in the Altai. The distribution of each endemic species is presented in terms of a standard geographic subdivision of the Altai region, with general conservation priorities discussed based on areas currently afforded protected status.