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AbstractThis review provides data on the possibilities for commercial use of algae of the green streptophyte genus Klebsormidium.It is one of the basal algal progenitors of land plants and shows many mechanisms and features which allow its adaptation to different environmental stresses associated with land colonization. This has led to formation of structures and compounds with countless possible applications in biotechnology and nanotechnology, starting from food to pharmaceuticals and biofuels. Therefore, the present work aims to provide: (1) a review on this yet neglected topic for the first time; (2) reliable identification using the polyphasic taxonomic approach of three local Klebsormidiumstrains isolated from soils of two protected areas in Bulgaria (Kresnendko Defile and National park Rila). It also outlines the cultivation advantages of Klebsormidiumbroad tolerance to harsh conditions and its reproductive features (easy disintegration and possibility to produce resting stages). The possibility to use inoculum of akinetes in soil algalization as biofertilizers is proposed. The results from standard microscopical identification and molecular data (ITSand rbcL, used separately and in combination), combined in the applied polyphasic approach led to distinguishing between geographically distinct strains collected at different altitudes. After identification of two strains (ACUS 00001 and ACUS 00014) as belonging to Klebsormidium dissectumand of ACUS 00207 as belonging to Klebsormidium klebsii, the similarity of the latter taxon with K. nitensis discussed.

AbstractCarotenoids have received particular attention both for their importance in algal systematics and hydrobiology and for their health benefits for humans, along with other applications in various industries. Here, we provide new data on the carotenoid content of five Vischeria/Eustigmatosstrains isolated from aeroterrestrial habitats in Bulgaria and kept in the Algal Collection of Sofia University (ACUS). The obtained pigment pattern with nine carotenoids and generalization of literature data allowed us to update the knowledge on the chemotaxonomic characteristics of Eustigmatophyceae with a total of 47 pigments reported for the group, out of which 37 are carotenoids. The important photosynthetic pigment lutein, considered also a high-value product with extensive applications in feed, food, nutraceutical and pharmaceutical industries, was proved as a novel carotenoid for the group. The results also confirmed the presence of luteoxanthin, which is rarely reported in algae. All strains had a high content of the commercially valuable health-promoting xanthophyll astaxanthin. There were also different amounts of beta-carotene, violaxanthin, vaucheriaxanthin, canthaxanthin, zeaxanthin and antheraxanthin. Based on the differences in the pigment composition of the members of the ecological groups of aquatic and aeroterrestrial species, we propose the existence of two main pigment types in the class Eustigmatophyceae, with the aquatic type further divided into freshwater and marine pigment subtypes.

AbstractRecently, scientists are focused on the discovery of alternative sources of high-value products such as proteins, lipids and carbohydrates. Microalgal cells have great potential for accumulation of bioactive components important in food, feed, pharmaceutical and cosmetics industry, as sources of biofuel, for waste water remediation, etc. The main advantages of microalgae as producers of bioactive components are fast biomass growth; short reproduction cycle; resistance to harsh conditions and contaminations; smaller area for growing in comparison with agriculture crops, etc. However, the production of high-value components from microalgae biomass is still associated with high costs, so efforts are focused on cost reduction. This study evaluated the possibilities for production of low-cost high-value products from two microalgal strains, Chlorela vulgarisCAUP H1993 and Desmodesmus communisCAUP H522. Microalgal biomass was grown under simple low-cost media supplemented with urea as nitrogen source for extraction of crude protein. To completely utilize the harvested biomass, we applied two consecutive steps of the extraction procedure for protein and lipids accumulated in the exhausted biomass. The media supplemented with urea was promising, especially for growing C. vulgarisH1993 CAUP. The results showed that after two consecutive extraction steps, it is possible to obtain 8–9.0% crude protein and 21–24% lipids from the exhausted dry biomass of D. communisand C. vulgaris, respectively.

AbstractMicroalgae are subject of extensive scientific and commercial interest in terms of both fundamental ecology and biotechnological potential. Here, we describe five Bulgarian aeroterrestrial strains of the Eustigmatos/Vischeriagroup, which have shown potential as valuable carotenoid producers. The strains are stored in the algal collection of Sofia University (ACUS). The main cytological and morphological diagnostic features of the studied eustigmatophycean stramenopile algae remained stable during long-term cultivation, showing that immediate light microscopy (LM) identification in cultures is reliable. We used a polyphasic approach for taxonomical identification, combining conventional microscopy of culture material with molecular-genetic methods (based on rbcLgene sequencing). This approach led to almost similar taxonomic results, supporting the need for unification of the genera Eustigmatosand Vischeria(which are presently separated on the basis of morphological features). Based on the obtained results, we speculate that there could be new eustigmatophyceaen aeroterrestrial taxa. This, however, needs to be confirmed in more refined molecular-genetic studies with a view to exploiting the full biotechnological potential of the aeroterrestrial Eustigmatos/Vischeriastrains described here.