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The effect of artificial light with different spectral compositions (white, WW; white–red, WR; white–blue, WB; and white–red—blue, WRB) on the wet weight, plant height, total leaf surface area, variable fluorescence parameters of photosystem 2 (PS2), and the content of the total fraction of essential oils in 30‑ and 50-day-old Cinnamon Aroma basil plants was studied. Thirty-day-old basil plants adapted to WB light were characterized by the highest chlorophyll content and the highest value of the photochemical quenching coefficient of PS2 fluorescence but by the smallest wet weight and total leaf surface as compared to plants grown in light with a different spectral composition. A longer adaptation (50 days) of the basil to illumination of a different spectral composition at the same intensity led to plant alignment in terms of chlorophyll content and height. A positive correlation was found between changes in the photochemical quenching coefficient of PS2 fluorescence and wet weight in 50-day-old plants. Fifty-day-old plants grown in light with a high proportion of red radiation (WR and WRB) and having generative shoots with buds contained the largest amount of the total fraction of essential oils.

The current problem with phosphorus fertilizers are shortage of rock phosphate from which it is produced and adverse impact of their production and use on the environment. A promising solution is use of phosphorus-rich biomass of microalgae as biofertilizer, but possible impact of such fertilizers on the biological activity and microbiome of soils remain unknown in many aspects. We investigated the effect of Chlorella vulgaris IPPAS C-1 (Chlorophyceae) biomass application on yield, biological activity, efficacy of the rhizobia- and cyanobacteria-based growth promoting formulations, as well as the microbiome of the soil during cultivation of beans (Phaseolus vulgaris L.) cvr. “Strela.” Total and specific yield, actual nitrification and denitrification, carbon dioxide and methane emission were determined for soil samples from the rhizosphere. The taxonomic structure of the prokaryotic community of the bean rhizosphere was determined by NGS of 16s rRNA gene amplicons on the Illumina platform. The metagenomic data were analyzed using software tools QIIME and VAMPS. It was found that the application of biomass of C. vulgaris IPPAS C-1 as a phosphorus biofertilizer increased the bulk yield of beans. It also allowed to achieve the specific yield (per plant) level provided by traditional fertilizers. The biomass application did not (i) impact the biological activity of the soil, (ii) did not increase the level of denitrification, and (iii) did not increase significantly the soil emission of the “greenhouse gases.” The Chlorella biomass application hamper the growth-promoting effect of the bacterial preparations made from rhizobia and cyanobacteria. Also, no significant changes in the taxonomic composition of the soil of the rhizosphere microbiome upon the application of the Chlorella biomass were revealed. Collectively, the results indicate the possibility of at least partial replacement of chemical fertilizers with phosphorus biofertilizers from microalgae biomass in the field growing of beans.

A prominent feature of stress-tolerant microalgae is their versatile metabolism, allowing them to synthesize a broad spectrum of molecules. In microalgae, they increase stress resilience of these organisms. In human body, they exhibit anti-aging, anti-inflammatory, and sunscreen activities. This is not surprising, given that many of the stress-induced deleterious processes in human body and in photosynthetic cell are mediated by the same mechanisms: free-radical attacks and lipid peroxidation. It is also worth noting, that the photosynthetic machinery of microalgae is always at risk of oxidative damage since high redox potentials and reactive molecules are constantly generated during its functioning. These risks are kept at bay by efficient reactive oxygen species elimination systems including, inter alia, potent low-molecular antioxidants. Therefore, photosynthetic organisms are a rich source of bioactive substances with a great potential for curbing the negative effects of stresses, acting on human skin cells on a day-to-day basis. In many cases these compounds appear to be less toxic, less allergenic, and, in general, more “biocompatible” than most of their synthetic counterparts. The same algal metabolites are recognized as promising ingredients for innovative cosmetics and cosmeceutical formulations. Ever increasing efforts are being put into the search for new natural biologically active substances from microalgae. This trend is also fueled by the growing demand for natural raw materials for foods, nutraceuticals, pharmaceuticals, and cosmetology, associated with the global transition to a “greener” lifestyle. Although a dramatic diversity of cosmeceuticals was discovered in macrophyte algae, single-celled algae are on the same level or even surpass them in this regard. At the same time, a large-scale biotechnological production of microalgal biomass, enriched with the cosmeceutical compounds, is more technically feasible and economically viable than that of macrophyte biomass. The autotrophic cultivation of microalgae is generally simpler and often cheaper than that of heterotrophic microorganisms. Cultivation in bioreactors makes it possible to obtain more standardized raw biomass, quality of which is less dependent on seasonal factors. Microalgae biotechnology opens many possibilities to the “green” cosmeceutical production. However, a significant part of microalgae chemo- and biodiversity remains so far untapped. Consequently, bioprospecting and biochemical characterization of new algal species and strains, especially those isolated from habitats with harsh environmental conditions, is a major avenue for further research and development. Equally important is the development of approaches to cost-effective microalgae cultivation, as well as induction, extraction, and purification of cosmeceutical metabolites. World scientific community is rapidly accumulating extensive information on the chemistry and diverse effects of microalgae substances and metabolites; many substances of microalgal origin are extensively used in the cosmetic industry. However, the list of extracts and individual chemicals, isolated from them and thoroughly tested for safety and effectiveness, is not yet very large. Although excellent reviews of individual microalgal cosmeceutical groups exist, here we covered all the most important classes of such compounds of cosmeceutical relevance, linking the patterns of their composition and accumulation with the relevant aspects of microalgae biology.

A prominent feature of stress-tolerant microalgae is their versatile metabolism allowing then to synthesize a broad spectrum of molecules with beneficial effects on many aspects of human body functioning. This is in line with the current understanding that many stress-induced deleterious processes in the human body and in photosynthetic cell are mediated by the same mechanisms such as free-radical attacks and lipid peroxidation. These related risks are kept at bay by optical screening of harmful UV, enzymatic ROS elimination systems, and potent low-molecular antioxidants. Microalgae synthesize a broad spectrum of compounds exerting antioxidant and/or UV-absorbing properties. In microalgae, they increase stress-resilience of these organisms. In human body, they exhibit photoprotective, antiaging, and sunscreen activities. Therefore, these algal metabolites were recognized as promising ingredients for innovative cosmetics and cosmeceutical formulations. Ever increasing effort is being invested into the search for new natural biologically active substances from microalgae. This trend is also fueled by the growing demand for natural raw materials for food, pharmaceuticals and cosmetology associated with the global transition to a "greener" lifestyle. Here, we review the currently accumulated knowledge about the main groups of cosmeceutical compounds from microalgae.

Studies of the impact of inorganic phosphorus (Pi), an important nutrient, on the growth and physiological parameters of single-celled algae are important for investigations of the dynamics of phytoplankton abundance and productivity in natural ecosystems as well as in industrial systems for the cultivation of microalgae. Difficulties in carrying out such studies are associated with the complex kinetics of Pi uptake by cells and the ability of microalgae to store phosphorus in their cells. This situation necessitates efficient methods for express monitoring of microalgal cultures, such as the methods based on the registration of optical properties of cells, in particular absorption and scattering of light and fluorescence of chlorophyll contained in the cells. Here, the results of monitoring the cultures of the chlorophyte Chlorella vulgaris IPPAS C-1 starving for phosphorus are described. It was found that both optical (light absorption in the bands of the key pigments—chlorophylls and carotenoids) and luminescent (variable fluorescence of chlorophyll) parameters closely reflect the culture condition. Registration of optical properties required correction for the contribution of light scattering to the overall extinction of light by microalgal cell suspensions. At the same time, the light scattering signal is an accurate measure of the total number of suspended particles in the suspension. However, it is difficult to monitor cultures containing a significant amount of light-scattering particles lacking photosynthetic pigments (such as heterotrophic bacteria). For such cultures, the use of variable fluorescence- based parameter Fv/Fm reflecting the maximum photochemical efficiency of the photosystem II is advisable.

We have conducted the analysis of sequences of the 16S rRNA gene and intergenic 16S–23S rRNA region (ITS) of nodule bacteria of soybean which differ in growth speed and are isolated from soils of Ukraine with different growth rate intensities. As a result we have shown the similarity of strains with an intense growth rate to soybean rhizobia of group USDA 123. The studied strains, as other representatives of this group, possess increased saprophytic competence. The restriction analysis divided all sequences of the intergenic ITS region of soybean rhizobia into two ITS types: the first ITS-type includes strains with an intensive growth rate and the second ITS -type contains strains with a slow grow rate. These types also coincide with their physiological groups.

A new taxonomic marker (the hin-region) for study of the diversity of Rhizobium bacteria at the species-groups of strains level was proposed. Groups of Rhizobium strains were isolated with its use that could not be detected by other methods that correlated with the evolutionary proximity of bacteria. This approach to the creation of marker systems allows one to effectively describe the intra- and inter-species genetic diversity of nodule bacteria and to provide an assessment of the prospects of their use in agricultural practices. The proposed marker system was used to describe Rhizobium genus bacterial samples that were isolated in different ecological and geographical regions of Ukraine.

The new taxonomic marker (hin-region) has been proposed, which gives possibility for Rhizobium bacteria study on “species — group of strains” level. Using this marker the groups of Rhizobium strains were determined, which could not be distinguished with other methods, and these results correlated with evolutionary similarity of the bacteria. The developed approach for creating marker systems allows to carry out effective inventory of inter- and intraspecies genetic diversity of nodulating bacteria and to evaluate perspectives of their use in agriculture. The proposed marker system was used for description of Rhizobium bacteria samples isolated from various ecological-geographical regions of Ukraine.

The Bacillus cereus group consists of closely related species of bacteria and is of interest to researchers due to its importance in industry and medicine. However, it remains difficult to distinguish these bacteria at the intra- and inter-species level. Bacillus thuringiensis (Bt) is a member of the B. cereus group. In this work, we studied the inter-species structure of five entomopathogenic strains and 20 isolates of Bt, which were collected from different geo-ecological regions of Ukraine, using various methods: physiological and biochemical analyses, analysis of the nucleotide sequences of the 16S rRNA and gyrB genes, by AP-PCR (BOX and ERIC), and by saAFLP. The analysis of the 16S rRNA and gyrB genes revealed the existence of six subgroups within theB.cereus group: B anthracis, B. cereus I and II, Bt I and II, and Bt III, and confirmed that these isolates belong to the genus Bacillus. All strains were subdivided into 3 groups. Seventeen strains belong to the group Bt II of commercial, industrial strains. The AP-PCR (BOX and ERIC) and saAFLP results were in good agreement and with the results obtained for the 16S rRNA and gyrB genes. Based on the derived patterns, all strains were reliably combined into 5 groups. Interestingly, a specific pattern was revealed by the saAFLP analysis for the industrial strain Bt 0376 р.о., which is used to produce the entomopathogenic preparation “STAR-t”.

The Bacillus cereus group consists of closely related species of bacteria and is of interest to researchers due to its importance in industry and medicine. However, it remains difficult to distinguish these bacteria at the intra- and inter-species level. Bacillus thuringiensis (Bt) is a member of the B. cereus group. In this work, we studied the inter-species structure of five entomopathogenic strains and 20 isolates of Bt, which were collected from different geo-ecological regions of Ukraine, using various methods: physiological and biochemical analyses, analysis of the nucleotide sequences of the 16S rRNA and gyrB genes, by AP-PCR (BOX and ERIC), and by saAFLP. The analysis of the 16S rRNA and gyrB genes revealed the existence of six subgroups within the B. cereus group: B anthracis, B. cereus I and II, Bt I and II, and Bt III, and confirmed that these isolates belong to the genus Bacillus. All strains were subdivided into 3 groups. Seventeen strains belong to the group Bt II of commercial, industrial strains. The AP-PCR (BOX and ERIC) and saAFLP results were in good agreement and with the results obtained for the 16S rRNA and gyrB genes. Based on the derived patterns, all strains were reliably combined into 5 groups. Interestingly, a specific pattern was revealed by the saAFLP analysis for the industrial strain Bt 0376 р.о., which is used to produce the entomopathogenic preparation STAR-t.