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Antarctic yeasts represent a poorly explored source of novel bioactive compounds with antineoplastic activity and a favorable toxicological profile. The present paper presents the newest data on the antiproliferative and antimicrobial potential of extracts obtained from the psychrophilic strain AL103 of the species Sporobolomyces roseus. The capacity of AL103 to grow under different cultivation conditions, including in a bioreactor system with optimal biomass quantities of approximately 6.0 g/L, was demonstrated. A comparative examination of the metabolic profiles (GC-MS-based) of yeast extracts revealed a wide variety of synthesized molecules responsible for the different levels of antineoplastic activity depending on the tissue origin of the malignant cell lines. Concentration response curves were generated by the MTT dye reduction test. The respective IC50 values were extrapolated and found between 35.3 and 163 µg/mL. The antibacterial potential of both extracts was evaluated with the broth microdilution test against four referent pathogenic bacterial strains. The estimated minimal inhibitory concentrations revealed a moderate antibacterial activity. According to the GC-MS results, both extracts are rich in long-chain fatty acids which are known for their antibacterial properties. In conclusion, the Antarctic strain AL103 possesses promising potential for further pharmacological investigations aiming to elucidate its application as a health-promoting food additive or/and as a source of biologically active compounds. [ABSTRACT FROM AUTHOR]

Featured Application: The developed chitosan films can be used as edible coatings to prolong the shelf-life of food products. Our results show that the rosehip oil-loaded chitosan films with an optimized composition possess good color, mechanical, barrier, antioxidant, and antimicrobial characteristics, which assist the preservation of minimal processed fruits. The concept of food packaging plays a crucial role in ensuring consumer satisfaction and extending the shelf life of food products. The rising trend of introducing innovative materials for food packaging has become prominent in recent years. The present study aims to investigate the impact of rosehip seed oil (RSO) on the physical, physicochemical, antioxidant, and antimicrobial properties of edible films based on chitosan for potential fruit packaging applications. Scanning electron microscopy revealed a uniform distribution of the incorporated emulsion throughout the edible film. The addition of RSO increased the deformation at break in both tensile and puncture test, thereby improving the elastic properties of the films. The resulting films exhibited a light-yellow color with high opacity. The immobilization of RSO led to a decrease in water content by almost two times and an increase in water vapor permeability of the films. The films showed enhanced antioxidant activity and retained good protective properties against the yeast S. cerevisiae. Consequently, these newly formulated multicomponent films are found to be suitable for applications in the development of active food packaging because of their physical, antioxidant, and antimicrobial properties. [ABSTRACT FROM AUTHOR]

Aerial herbal substances from Ailanthus altissima were the subject of the present study, which aimed to follow the dynamics in the accumulation of bioactive compounds with antioxidant potential during vegetation, namely polyphenols, flavonoids, phenolic acids, and tannins quantified by pharmacopoeial methods. Aqueous and ethanolic extracts from dry plant material (under reflux and heating at 200°C) and ethanolic extracts from fresh plant material (under vacuum) were prepared to determine the optimal conditions for the extraction process of the antioxidant active components. Radical scavenging activities (according to ABTS and DPPH in vitro assays) were found for all tested extracts. Flower buds and flower extracts demonstrated the best results, followed by leaves and stem bark, which correlated with the total polyphenols and flavonoid content found. Vacuum extracts of flowers collected at the beginning of flowering were distinguished by the strongest antioxidant potential (3272.28 ABTS mmol TE/g dw and 2125.67 DPPH mmol TE/g dw). The same type of extract is also suitable for stem bark (411.61 ABTS mmol TE/g dw) for which the collection period is the beginning and the end of the growing season. Ethanolic leaf extracts (collected at the beginning flowering stage) with the application of temperature treatment exhibited the best antioxidant potency (504.75 ABTS mmol TE/g dw and 404.72 DPPH mmol TE/g dw) for this plant substance. The results of the present study provide a good basis for future research on Ailanthus altissima intending to incorporate it into phyto-preparations with strong antioxidant activity. [ABSTRACT FROM AUTHOR]

This article attempts to summarize the available data on wild edible macromycetes in the regions Strandzha and the Black Sea coast in connection with the clarification of ethnomycology. The total number of registered species of edible mushrooms for both areas is 105. The species Boletus caucasicus Singer ex Alessio; Boletus luridiformis Rostk. var. luridiformis and Laccaria bicolor (Maire) P.D. were noted only for the region of the Black Sea coast. The species composition, ecological-trophic structure and seasonality of edible mushrooms are briefly discussed. A list of 14 macroscopic edible fungi with conservation significance for the mycota of the two territories, assessed with the latest IUCN criteria, is given. Critically Endangered (CR) according to the Red List of fungi in Bulgaria and the Red Data Book of the Republic of Bulgaria was Boletus caucasicus Singer ex Alessio. [ABSTRACT FROM AUTHOR]

Microorganisms are ubiquitous. Different habitats are associated with a variety of environmental factors that suggest rich biodiversity. Many of them live in various ecological, extreme niches, producing exopolysaccharides (EPSs) as a defense mechanism in response to harsh environmental conditions. Exopolymers possess unique properties because of the diverse сrude habitats that generally characterize by atypical conditions as pH, salinity, temperatures, toxicity, pressure and radiation levels that stimulate the microbes to secret these substances. They offer a variety of structures due to the presence of different functional groups such as uronic acids, phosphate groups and sulfated units. The microorganisms, called extremophiles, are of significant biotechnological, medical, biomedical and ecological importance as their enzymes and exopolysaccharides possess properties that offer knowledge into their evolution, functional properties and biology. Their unique products can be transformed into valuable applications vary from wastewater treatment to the genetic diseases. This review present extremophilic microorganisms and their adaptation mechanisms that focus on the production of EPSs and their ecological function, physiological role for the cell, physicochemical properties and different applications. The remarkable versatility and efficacy of these extremophile-derived biopolymers offer novel opportunities for innovation and development in the industrial and biotechnological sectors. [ABSTRACT FROM AUTHOR]

Studies on the surface-active agents added during the cultivation process proved their effect on the synthesized bioproducts. The biosynthesis and accumulation of exopolysaccharide and biomass by Antarctic producer Cryptococcus laurentii AL65 were studied in submerged cultivation using different carbon sources in the culture medium added to a one-percent concentration (pentoses, hexoses and oligosaccharides). Sucrose was chosen as the most appropriate carbon source for the cell growth and extracellular polymer biosynthesis. Absorption of sucrose by a strain producer was monitored and the residual sugars were traced in the dynamics of the fermentation process. The effect of polyoxyethylene sorbitan monooleate (Tween 80) on the cell growth and the accumulation of the synthesized biopolymer were studied for the first time with the Antarctic producer. The optimal increase in the amount of accumulated exopolysaccharide was recorded at a concentration of 6% Tween 80 at 24 h from the start of fermentation. The surfactant treatment contributed to an increase in the total amount of lipids in the cell, to the increased [ABSTRACT FROM AUTHOR]

The current study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from soil and penguin feathers samples collected on Livingston Island (Antarctica). The strains were identified as belonging to the species Leucosporidium yakuticum (LY) and Cystobasidium ongulense (CO) based on molecular genetic analysis. The EPS production was investigated using submerged cultivation. Different chemical, chromatographic, and spectral analyses were employed to characterize EPSs. LY accumulated 5.5 g/L biomass and 4.0 g/L EPS after 120 h of cultivation, while CO synthesized 2.1 g/L EPS at the end of cultivation, and the biomass amount reached 5.5 g/L. LY-EPS was characterized by a higher total carbohydrate content (80%) and a lower protein content (18%) by comparison with CO-EPS (62%, 30%). The LY-EPS mainly consisted of mannose (90 mol%), whereas CO-EPS had also glucose, galactose, and small amounts of uronic acids (8–5 mol%). Spectral analyses (FT-IR and 1D, 2D NMR) revealed that LY-EPS comprised a typical β-(1 → 4)-mannan. Branched (hetero)mannan, together with β/α-glucans constituted the majority of CO-EPS. Unlike LY-EPS, which had a high percentage of high molecular weight populations, CO-EPS displayed a large quantity of lower molecular weight fractions and a higher degree of heterogeneity. LY-EPS (100 ng/mL) elevated significantly interferon gamma (IFN-γ) production in splenic murine macrophages and natural killer (NK) cells. The results indicated that newly identified EPSs might affect IFN-γ signaling and in turn, might enhance anti-infectious responses. The data obtained also revealed the potential of EPSs and yeasts for practical application in biochemical engineering and biotechnology. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pollution by heavy metals poses serious environmental problems and is dangerous to human health, so considerable attention has been given to methods for their removal from industrial effluents. The need for highly effective biosorbents able to remove heavy metals from waste waters, even at the low concentrations which are still toxic for living organisms in ecosystems, is a topical problem. RESULTS: In the present study, psychrophilic yeast strain Cryptococcus laurentii (AL65) was used to explore its potential for biosorption of metal ions. The accumulation of biomass was followed continuously in the context of bioreactor cultivation. An adsorption experiment of caustic pretreated biomass was conducted in batch mode with synthetic mixed solution in the pH range 4.7–7.0, and ion concentrations of individual metals were simultaneously determined by inductively coupled plasma ‐ optical emission spectrometry (ICP‐OES). Biosorption abilities were determined for 15 elements: the total amount of adsorbed ions was 68 mg g−1 dry biomass for 10 mg L−1 initial concentration of each element in the solution, and 113 mg g−1 for 20 mg L−1. The highest adsorption capacity was observed in the 20 mg L−1 solution for aluminium, chromium, indium, gallium, iron and bismuth in the range 12–16 mg g−1 dry biomass at an optimal pH of ≈5. CONCLUSION: The results on the biosorption ability of Antarctic producer Cryptococcus laurentii (AL65) can be used in the optimization of technological processes for the removal of heavy metals from aqueous solutions. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The current study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from soil and penguin feathers samples collected on Livingston Island (Antarctica). The strains were identified as belonging to the species Leucosporidium yakuticum (LY) and Cystobasidium ongulense (CO) based on molecular genetic analysis. The EPS production was investigated using submerged cultivation. Different chemical, chromatographic, and spectral analyses were employed to characterize EPSs. LY accumulated 5.5 g/L biomass and 4.0 g/L EPS after 120 h of cultivation, while CO synthesized 2.1 g/L EPS at the end of cultivation, and the biomass amount reached 5.5 g/L. LY-EPS was characterized by a higher total carbohydrate content (80%) and a lower protein content (18%) by comparison with CO-EPS (62%, 30%). The LY-EPS mainly consisted of mannose (90 mol%), whereas CO-EPS had also glucose, galactose, and small amounts of uronic acids (8-5 mol%). Spectral analyses (FT-IR and 1D, 2D NMR) revealed that LY-EPS comprised a typical β-(1 → 4)-mannan. Branched (hetero)mannan, together with β/α-glucans constituted the majority of CO-EPS. Unlike LY-EPS, which had a high percentage of high molecular weight populations, CO-EPS displayed a large quantity of lower molecular weight fractions and a higher degree of heterogeneity. LY-EPS (100 ng/mL) elevated significantly interferon gamma (IFN-γ) production in splenic murine macrophages and natural killer (NK) cells. The results indicated that newly identified EPSs might affect IFN-γ signaling and in turn, might enhance anti-infectious responses. The data obtained also revealed the potential of EPSs and yeasts for practical application in biochemical engineering and biotechnology., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)