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In the present study we report on the isolation of 12 strains of filamentous fungi from the rhizosphere of Leucojum aestivum L. (Amaryllidaceae). They were screened for ability to transform the Amaryllidaceae alkaloid lycorine. Gas chromatography-mass spectrometry was applied to analyze the samples. The Talaromyces pinophilus S120 strain was found to transform 19% of lycorine into its 2-oxo-derivative. To the best of our knowledge, this is the first report on transformation of lycorine by a filamentous fungus.

In this paper, a new hybrid MpGA-CS is elaborated between multi-population genetic algorithm (MpGA) and cuckoo search (CS) metaheuristic. Developed MpGA-CS has been adapted and tested consequently for modelling of bacteria and yeast fermentation processes (FP), due to their great impact on different industrial areas. In parallel, classic MpGA, classic CS, and a new hybrid MpGA-CS have been separately applied for parameter identification of E. coli and S. cerevisiae FP models. For completeness, the newly elaborated MpGA-CS has been compared with two additional nature-inspired algorithms; namely, artificial bee colony algorithm (ABC) and water cycle algorithm (WCA). The comparison has been carried out based on numerical and statistical tests, such as ANOVA, Friedman, and Wilcoxon tests. The obtained results show that the hybrid metaheuristic MpGA-CS, presented herein for the first time, has been distinguished as the most reliable among the investigated algorithms to further save computational resources.

Sialic acids (Sia) represent a set of derivatives of nine-carbon sugar neuraminic acid that occupy a terminal position in oligosaccharide chains located on the surface of cells. They are very important for several physiological and pathological processes, including bacterial and viral infections. Until recently, Sia had been described mostly in animals, viruses, bacteria and protozoan species. In the last years, information on sialic acids existence in filamentous fungi has been published, but these data are very scarce. The same is valid for the enzymes that are involved in the synthesis, transport and degradation of Sia in fungi. So far, most data known regarding fungal sialidases are a result of published complete fungal genomes. However, based on the accumulated data, it appears that the kingdom of fungi probably harbours hitherto unknown mechanisms and enzymes of sialic acid metabolism. This review attempts to present the state of knowledge on sialic acids in fungi with respect to their structure, diversity and biological role, as well as Sia metabolism and enzymes involved in their conversion. The summary is presented at the background of the respective metabolic mechanisms possessed by eukaryotes and prokaryotes. The possible role of sialome and sialometabolism in fungi are also discussed.

Aim: The aim of the study was to be thoroughly examined the chemical and lipid composition of three species of wild edible mushrooms (Boletus pinophilus, Cantharellus cibarius and Craterellus cornucopioides) grown in Bulgaria as well as performing a principal component analysis in order to clarify specific relationships between the species and their nutritional compositions. Methods: Standard methods following the ISO procedures were used for determination of the components. Results: Moisture, crude fat, proteins, total carbohydrates, crude fibre and ash were determined in the examined mushroom species. Potassium and phosphorus were the essential elements in the mushrooms. Unsaturated fatty acids predominated in the lipid fraction of triacylglycerols, and oleic acid was the main one. Ergosterol was the major sterol in the lipid fraction of all mushrooms (42.4 – 72.8%). Phospholipid composition of the mushrooms differed, and phosphatidic acids were the main class in B. pinophilus and C. cibarius, while in C. cornucopioides all phospholipid classes were present in similar quantities. Fatty acid composition of the main phospholipid classes of the mushrooms was determined for the first time and was observed that saturated fatty acids (51.2 – 73.3%) predominated in all main phospholipids except in phosphatidic acids from C. cornucopioides, where unsaturated fatty acids prevailed (54.9%). Conclusion: Some key differences were observed in the chemical and lipid composition of the examined mushroom species but all of them were abundant in valuable fat-soluble biologically active components which made them suitable for possible application as food additives in many products and functional foods.

Camelina sativa (L.) is an old oil crop that is gaining interest due to its low impact on the environment and wide range of application. Camelina seeds can be used as a food ingredient and raw material for the production of oil. Chemical composition and the content of fat-soluble biologically active components of four varieties Camelina sativa (L.) seeds were investigated. The proteins content was from 25.8 % to 28.1% and carbohydrates from 32.0 to 35.4%, respectively. The oil content of the seeds was 26.8%, 27.8%, 29.2% and 29.3%, respectively. Unsaturated fatty acids, which were presented mainly as oleic (21.7 – 26.3%), linolenic (16.4 – 20.4%), linoleic (14.8 – 19.9%) and gadoleic (15.7 – 17.7%) acids, predominated in triacylglycerols. Total content of phospholipids in the oil, mainly phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine and phosphatidic acids was 12.0%, 12.1%, 15.0% and 16.7%, respectively. The amount of sterols was found to be 0.6% in the oil and beta-sitosterol predominated (68.3 – 71.4%) followed by campesterol (25.1 – 27.4%). Total tocopherol content was relatively higher (785 – 1075 mg/kg) than those in other seed oils. Gamma-tocopherol prevailed in tocopherol fraction in the oils (more than 90.0%).

Sialidases (neuraminidases, EC 3.2.1.18) are widely distributed in biological systems such as viruses, bacteria, protozoa, as well as in the deuterostome lineage of animals. But there are only scarce data on the sialidase production by filamentous fungi, especially isolated from native sources. The aim of this study was to obtain information about sialidase distribution in filamentous fungi from non-clinical isolates, to determine availability of sialidase gene, and to select a perspective producer. A total of 113 fungal strains belonging to Ascomycota and Zygomycota compassing 21 genera and 51 species were screened. Among them, 77 strains (11 orders, 14 families and 16 genera) were able to synthesize sialidase. Penicillium, Aspergillus, Cladosporium, Alternaria, Talaromyces, and Mucor were the dominant genera, and P. griseofulvum, P. crustosum, P. fimorum, and P. rubens, as well as A. niger and A. fumigatus were the dominant species. Present data showed a habitat-dependent variation of sialidase activity between species and within species, depending on location. Sialidase gene was identified in sialidase-positive and sialidase-negative strains. The presence of Asp boxes and R-I/L-P motif and a mass about 40 kDa characterized this protein as sialidase. Among three perspective strains, P. griseofulvum Р29, P. fimorum ІІІ 7-1 and A. niger A 3-2, the best producer was chosen based on their sialidase production depending on type of cultivation, medium composition, and growth temperature. The selected P. griseofulvum Р29 was cultivated in 3L bioreactor at 20°C on medium supplemented with 0.5% milk whey. The results demonstrated better growth and 2.3-fold higher maximum enzyme activity compared to the shaken flask cultures. Moreover, the early occurring maximum (48 h) is an important prerequisite for future up scaling of the process.

Department of Chemical Technology, University of Plovdiv ‘Paisii Hilendarski’, 24 Tzar Asen Str., 4000 Plovdiv, Bulgaria E-mail: zhanapetkova@uni-plovdiv.net Manuscript received online 20 October 2020, revised and accepted 31 October 2020 Nowadays, the demand of underused plants which may be a new sources of bioactive compounds is constantly growing. For that reason, the lipid composition of bitter vetch seed oil (Vicia ervilia L.) has been examined. The plant has Russian origin but has been introduced in southern Bulgaria. The oil content of the seeds is rather low (1.4%), but the lipids are rich in unsaponifiable matter (39.7%) – phytosterols (4.7%), tocopherols (4010 mg/kg) and carotenoids (684 mg/kg). Unsaturated fatty acids (73.4%) predominate in the glyceride oil and the main ones are oleic (52.0%) and linoleic (20.4%) acids. The ma­jor saturated fatty acid is palmitic with amount of 20.8%. The quantity of monounsaturated fatty acids (52.6%) is higher than that of polyunsaturated (20.8%) ones. β-Sitosterol (83.3%) is the main component in the sterol fraction, followed by campesterol (12.1%). Only two tocopherols (α- and Ƴ-) are identified in the tocopherol fraction, in which y-tocopherol predominates (87.6%). Total phospholipids in bitter vetch seeds are 0.7% and the major component is phosphatidylinositol (28.9%). Fatty acid com­position of three classes of the phospholipids (phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine) in the seeds has also been examined. Oleic acid is the main fatty acid in the last two phospholipids (61.1 and 48.2%, respectively), while palmitic acid (46.8%) predominates in phosphatidylinositol. These results depict that the oil from bitter vetch seeds is a promising source of bioactive components and can be successfully implemented in different functional food ingredients.

The water cycle algorithm (WCA), which is a metaheuristic method inspired by the movements of rivers and streams towards the sea in nature, has been adapted and applied here for the first time for solving such a challenging problem as the parameter identification of fermentation process (FP) models. Bacteria and yeast are chosen as representatives of FP models that are subjected to parameter identification due to their impact in different industrial fields. In addition, WCA is considered in comparison with the genetic algorithm (GA), which is another population-based technique that has been proved to be a promising alternative of conventional optimisation methods. The obtained results have been thoroughly analysed in order to outline the advantages and disadvantages of each algorithm when solving such a complicated real-world task. A discussion and a comparative analysis of both metaheuristic algorithms reveal the impact of WCA on model identification problems and show that the newly applied WCA outperforms GA with regard to the model accuracy.

Nowadays, the requirements of new sources of natural food components are constantly expanding worldwide. On one hand, the constituents derived from the common agriculture plants satisfy the needs of the body to function properly. On the other hand, the price of producing ordinary foods is gradually increasing. For that reason, it is necessary to find a cheaper alternative industrial crops, such as a specific variety of lupin (Lupinus angustifolius L. cultivar “Boregine”). The chemical and lipid composition of lupin seeds as well as the physicochemical characteristics of the oil were examined. The seeds are rich in proteins and carbohydrates, mainly starch, but have low oil content. Sucrose was the main soluble sugar and the major amino acids were phenylalanine, arginine, tyrosine and serine. Linoleic and oleic acids were predominate in the oil; β-sitosterol and γ-tocopherol were the main components in the sterol and tocopherol fractions, respectively. Phosphatidylinositol and phosphatidylcholine represented more than 50% of all phospholipids and oleic acid was in the highest amount in all phospholipid classes. All physicochemical characteristics of lupin seed oil were in agreement with the requirements for edible oils and its oxidative stability at 100 °C and an air flow rate of 20 L/h was extremely high (more than 100 h). Lupin seeds have high nutritional value and their oil depicts to be stable, which makes them a possible source of high quality lipids with long shelf life.

Bulgaria has a very rich fungal flora due to its phytogeographical position. The screening of chemical content and active substances of mushrooms becomes an important subject not only for Bulgaria but also for all over the world. In the last decade, Analyses on phytochemical and biological activity of fungi have gradually increased as a result of improvement in the number and quality of facilities. In the scope of the present research, medicinal mushrooms; Craterellus tubaeformis was analyzed for fatty acid compositions by GC-FID, tocopherols by HPLC-fluorescence, and Oil content by Soxhlet. The ongoing research will lead to a new generation of foods, and will certainly promote their nutritional and medicinal use.

Two fungal strains, isolated from Livingston Island, Antarctica (Penicillium commune 161, psychrotolerant and Aspergillus glaucus 363, mesophilic) were investigated for a relationship between growth temperature and oxidative stress response. Cultivation at temperatures below – (10 and 15°C and 10 and 20°C for P. commune and A. glaucus, respectively) and above (25°C and 30°C for P. commune and A. glaucus, respectively) the optimum caused significant difference in growth and glucose uptake in comparison with the control cultures. Enhanced level of reserve carbohydrates (glycogen and trehalose) was determined under cultivation at different temperatures from the optimal one. While the highest content of trehalose was found in the exponential phase, glycogen accumulation was observed in the stationary phase when growth conditions deteriorate. The growth at temperature below– and above–optimum caused strain–dependent changes in two antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). While SOD activity in the psychrotolerant strain increases with decreasing of growth temperature, the mesophilic A. glaucus demonstrated marked reduction of it at below– and above–optimal temperature. Decreasing trend of CAT activity was observed in both strains below the optimal temperature indicating a lack of antioxidant protection from this enzyme under the cold stress conditions.

Because of the crucial role of ligninolytic enzymes in a variety of industrial processes, the demand for a new effective producer has been constantly increasing. Furthermore, information on enzyme synthesis by autochthonous fungal strains is very seldom found. Two fungal strains producing ligninolytic enzymes were isolated from Bulgarian forest soil. They were identified as being Trametes trogii and T. hirsuta. These two strains were assessed for their enzyme activities, laccase (Lac), lignin peroxidase (LiP) and Mn-dependent peroxidase (MnP) in culture filtrate depending on the temperature and the type of nutrient medium. T. trogii was selected as the better producer of ligninolytic enzymes. The production process was further improved by optimizing a number of parameters such as incubation time, type of cultivation, volume ratio of medium/air, inoculum size and the addition of inducers. The maximum activities of enzymes synthesized by T. trogii was detected as 11100 U/L for Lac, 2.5 U/L for LiP and 4.5 U/L for MnP after 14 days of incubation at 25°C under static conditions, volume ratio of medium/air 1:6, and 3 plugs as inoculum. Among the supplements tested, 5% glycerol increased Lac activity to a significant extent. The addition of 1% veratryl alcohol had a positive effect on MnP.

Cold-induced oxidative stress during the aging of three Penicillium strains (two Antarctic and one from a temperate region) in stationary culture was documented and demonstrated a significant increase in the protein carbonyl content, the accumulation of glycogen and trehalose, and an increase in the activities of antioxidant enzymes (superoxide dismutase and catalase). The cell response to a temperature downshift depends on the degree of stress and the temperature characteristics of the strains. Our data give further support for the role of oxidative stress in the aging of fungi in stationary cultures. Comparing the present results for the stationary growth phase with our previous results for the exponential growth phase was informative concerning the relationship between the cold-stress response and age-related changes in the tested strains. Unlike the young cells, stationary-phase cultures demonstrated a more pronounced level of oxidative damage, as well as decreased antioxidant defence.

Despite the intensive research in the past decade on the microbial bioaccumulation of heavy metals, the significance of redox state for oxidative stress induction is not completely clarified. In the present study, we examined the effect of redox-active (copper and chromium) and redox-inactive (cadmium) metals on the changes in levels of oxidative stress biomarkers and antioxidant enzyme defence in Trichosporon cutaneum R57 cells. This filamentous yeast strain showed significant tolerance and bioaccumulation capability of heavy metals. Our findings indicated that the treatment by both redox-active and redox-inactive heavy metal induced oxidative stress events. Enhanced concentrations of Cu2+, Cr6+ and Cd2+ caused acceleration in the production of reactive oxygen species (ROS), increase in the level of oxidatively damaged proteins and accumulation of reserve carbohydrates (glycogen and trehalose). Cell response against heavy metal exposure also includes elevation in the activities of antioxidant enzymes, superoxide dismutase and catalase, which are key enzymes for directly scavenging of ROS. Despite the mentioned changes in the stress biomarkers, T. cutaneum did not show a significant growth diminution. Probably, activated antioxidant defence contributes to the yeast survival under conditions of heavy metal stress.

The lipid composition of the seed oil of three varieties (L-74, VIR-11 and BGR-455) of Lallemantia iberica Fisch. & Mey. (Lamiaceae) harvested in Bulgaria was examined in detail. Triacylglycerols (TAG >90%), phospholipids ( 90%) in the tocopherol fraction. Palmitic acid (16:0) was the major fatty acid of the phospholipids and oleic acid (cis 9-18:1) dominated in the sterol ester fraction. The three varieties have similar lipid compositions with BGR-455 being slightly more saturated. Due to its composition, Lallemantia oil might compete successfully with flax and other plant oils as a source of linolenic fatty acid in industrial and dietary applications.

A laboratory technological scheme for biosynthesis of exopolysaccharides and biomass from Antarctic yeasts and extraction of phospholipids and fatty acids from the biomass was developed. The strains Sporobolomyces salmonicolor AL34, Cryptococcus laurentii AL62, Isolate AL65, Isolate AL66, Cryptococcus laurentii AL100 and Isolate AL102 were selected as active producers of exopolysaccharides, and the biomass was a source of biologically active compounds. The chemical composition of the extracellular polymeric substances was analyzed and it was established that they contained about 80.0 % carbohydrates, 11.4% protein, 6.0 - 9.2% ash, nucleic acids - 4.7 - 6.0% and the biomass contained 10.5 - 13.5 % lipids. The accumulation of polar and non-polar lipids in the biomass produced at submerged and surface cultivation of the strains was studied. The content of phospholipids was found to be 0.1 - 0.4% in the biomas and 6.3 - 50.0% in the lipid fraction. In the submerged and surface cultures of the investig...

Vibrio cholerae non O1 26/06, a non-pathogenic strain, was subjected to treatment by different concentration of paraquat (PQ) and H2O2. Exposure to PQ for 1 h caused induction of reactive oxygen species (ROS) such as superoxide anion radical (•O2−) and H2O2. At the same time, second stress factor significantly inhibited •O2− production and enhanced the intracellular H2O2 content. The enhanced ROS generation resulted in a significant increase in the levels of oxidatively damaged proteins in comparison to the control variant. Thus, the exposure of V. cholerae cells to PQ and H2O2 promoted oxidative stress. Cell response against this stress includes activation of antioxidant enzyme defence. The treatment with PQ concentrations in the range of 0 - 5 mM resulted mainly in activation of SOD, but not noticeably changed CAT activity in V. cholerae non-O1 26/06. In contrast, effect of H2O2treatment on antioxidant enzyme synthesis in our Vibrio strain was still much more pronounced for CAT than for SOD. The...

To evaluate the concept of metabolic cold adaptation in Antarctic fungi, we compared the activities of several key enzymes of the glycolytic pathway and the TCA cycle (hexokinase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, and malate dehydrogenase) in psychrotolerant Penicillium sp. 161 and mesophilic Aspergillus glaucus 363 during both the stress exposure (6 h) and recovery phases. Mycelia of the Antarctic strains, grown until middle exponential phase at optimal temperature, were shifted to colder temperatures, i.e., 4 and 10 °C. Our investigations showed a re-routing of carbon metabolism away from glycolysis into the pentose phosphate pathway (PPP), which serves as a cellular stress-resistance mechanism under cold stress conditions. Moreover, the data clearly suggest strain-dependent differences in cold stress response concerning TCA enzyme activities between both fungi. The psychrotolerant strain induces glyoxalate cycle activities and the mesophilic strain uses a reduction of respiratory activity. A recovery response after removal of the stress factor was observed.

OBJECTIVE Deleterious effects of free radicals do not only result from the amount of free radicals produced but also are related to the efficiency and to the activities of enzymatic antioxidant systems. We investigated the effect of exogenous superoxide dismutase (SOD1) or Cu-chelating agent diethyldithiocarbamate (DDC) on the apoptosis (caspase-3 activity) of human granulosa luteinized cells (hGLC) in vitro. METHODS The effects of SOD1 and DDC were studied using in vitro culture system, caspase-3 and the total SOD activity in hGLCs were measured using AcDEVD-PNA substrate and Beaushap and Fridovich methods, respectively, after 48 h of the culture period. RESULTS The activity of SOD1 was the lowest in GLCs treated with 100 µM DDC as compared to control cells and to the cells supplemented with Cu, Zn-SOD or DDC (10 µM). The effect of DDC was associated with elevated caspase-3 activity as compared to control cells. CONCLUSIONS It was demonstrated for the first time that the supplementation of cultured hGLCs with Cu2+, Zn2+-SOD (200 U/ml) maintains the viability of hGLCs via caspase-3 suppression.

The Free Radical/Oxidative Stress Theory of Aging postulated that the accumulation of damage caused by reactive oxygen species (ROS) was the underlying mechanism by which organisms age. Our previous studies reported that the growth at low temperature caused oxidative stress events in Antarctic strains, including enhanced ROS generation. However, there is no data about age-related differences in cold stress-induced ROS accumulation in microorganisms living permanently in cold environments. The aim of the present paper was to evaluate the growth-phase-related changes in ROS level in two Antarctic strains belonging to different thermal classes, psychrotolerant (Penicillium olsonii p14) and mesophilic (Penicillium waksmanii m12) and the role of cold adaptation in this process. Intact cells and mitochondrial fractions from the middle exponential phase or stationary phase at optimal temperature were exposure to temperature of 6°C and 15°C, respectively. The results demonstrated that the temperature down...

In the present study, we examined the adaptive response of the filamentous fungus Humicola lutea 103 to copper stress. Our findings indicate that pretreatment with low concentrations of copper ions led to the development of resistance to high concentrations of the same heavy metal. Spores subjected to 40 µg/ml Cu ++ showed higher resistance to killing by subsequent incubation in 70 or 150 µg/ml Cu ++ compared to the single treatment. Pre-exposure strategy also caused a higher amount of biomass accumulation and recovery of the fungal growth curves to the control curves shape. Moreover, this strategy exerted protective effect against the oxidative damaged proteins in H. lutea cells, which was accompanied by a corresponding accumulation of reserve carbohydrates such as trehalose and glycogen. Adaptive cell response included induction in the activity of the first antioxidative enzyme superoxide dismutase, but catalase activity was independent of copper treatment and pretreatment. Therefore, we concluded that the pre-exposure to mild copper stress induces a coordinated response that decreases the oxidative stress degree in H. lutea cells when this pre-exposure was followed by severe stress.

Psychrophilic yeast strains Rhodotorula glutinis AL107, Sporobolomyces roseus AL108, Cryptococcus albidus AL55, Cryptococcus laurentii AL56 and Cryptococcus laurentii AL58 isolated from soil sample taken from the region of the Bulgarien base on Livingston Island, Antarctica, were studied. The biomass production was followed after cultivation of the yeasts in a medium with pH 5.3 at 15°C for 120 h. The biomass concentration by psychrophilic yeast strains was: R. glutinis AL107-6.05 g/l, S. roseus AL108-5.78 g/l, Cr. albidus AL55, Cr. laurentii AL56 and Cr. laurentii AL58-6.52 g/l, 6.84 g/l and 6.24 g/l, respectively.The extracted and separated lipids from the samples were supplied to analysis and the compositions of fatty acids, phospholipids, sterols as well as tocopherols were determined. Unsaturated fatty acids, mainly oleic (58.6–63.5%) and of saturated palmitic (18.2–24.5%), predominated in triacylglycerols. Sterols (0.1–0.3%) were valued in the dry yeast biomass. The content of phospholipids,...

The changes in the content and composition of total fatty acids, phospholipids and sterol esters, and their fatty acids, and of free sterols and tocopherols in developing seeds of a selection of high oleic acid sunflower varieties grown in Bulgaria were examined over a period of 15th to 90th day after flowering by means of various chromatographic methods. Under the climatic and geographical conditions typical for the South-East Balkans phospholipid, sterol-, sterol ester- and tocopherol- species are formed practically completely in the first 15 days after flowering. Until the 90th day, only quantitative changes were detected to give a product with 65% oil content, 1% phospholipids, 0.3% total sterols and 0.09% tocopherols. Oleic acid is the main component in all acyl derivatives, reaching 85% of the total fatty acids while palmitic and stearic acid content is about 4% each. The product is a good quality HOSO with beneficial content of FA and good prospects as a salad and cooking oil.

Antioxidant enzymes are essential for living cells, producing protection from reactive oxygen species such as superoxide, which cause oxidative damage to cell structures. Superoxide dismutase (SOD) and catalase (CAT) activities were determined for three Vibrio strains (Vibrio cholerae non O1/29, V. cholerae non O1/29-T and V. cholerae non O1/26) aerobically grown at 30°C (optimal level) and 10 °C (cold stress). All strains tested expressed both antioxidant enzymes under normophysiological and stress conditions, but the cell response is more strain-dependent than dependent on temperature. Levels of SOD in cultures of V. cholerae non O1/26 grown at 30°C were about 2.5 to 9.5-times higher than those in the cultures grown at 10°C. In contrast, SOD activity in V. cholerae non O1/29 increased by 7.5-fold under stress conditions in comparison to that at optimal temperature. The strain V. cholerae non O1/29-T did not show any significant difference in the cell response depending on the growth temperature....

Microbiological investigations of cultural heritage may be helpful in the choice of possible intervention for the prevention of biological degradation of works of art. Fungi presented in stone, fretwork and fresco samples from different objects in Rila monastery were isolated and characterized. Pure cultures of 9 strains were obtained and tested for their ability to grow (mycelia mat radial extension) on four agar media at temperature 30°C. The best growth occurred on Sabouraud agar, beer agar and potato glucose agar.Cultivation of four strains in jar bioreactors on Sabouraud medium for assessment of growth phase, glucose consumption and protein synthesis was performed. Extensive mycelia development could even be seen at 12 h of the cultivation starting at a time when glucose was abundant in the culture medium. Maximal biomass was attained at 72 or 84 h of growth. A sharp increase in extracellular protein synthesis was noted in the early stages of growth. The data indicated that all cultures were ...

Over the last decades, the Antarctic regions have been investigated mainly for the presence and exploitation of psychrophilic bacteria and archea, occasionally for algae and more rarely for fungi. ...

The Antarctic fungal strain Aspergillus glaucus 363 produces cold-active (CA) Cu/Zn-superoxide dismutase (SOD). The strain contains at least one gene encoding Cu/Zn-SOD that exhibited high homology with the corresponding gene of other Aspergillus species. To our knowledge, this is the first nucleotide sequence of a CA Cu/Zn-SOD gene in fungi. An effective laboratory technology for A. glaucus SOD production in 3 L bioreactors was developed on the basis of transient cold-shock treatment. The temperature downshift to 10 °C caused 1.4-fold increase of specific SOD activity compared to unstressed culture. Maximum enzyme productivity was 64 × 103 U kg−1 h−1. Two SOD isoenzymes (Cu/Zn-SODI and Cu/Zn-SODII) were purified to electrophoretic homogeneity. The specific activity of the major isoenzyme, Cu/Zn-SODII, after Q-Sepharose chromatography was 4000 U mg−1. The molecular mass of SODI (38 159 Da) and of SODII (15 835 Da) was determined by electrospray quadropole time-of-flight (ESI-Q-TOF) mass spectrometry and dynamic light scattering (DLS). The presence of Cu and Zn were confirmed by inductively coupled plasma mass spectrometry (ICP-MS). The N-terminal amino acid sequence of Cu/Zn-SODII revealed a high degree of structural homology with Cu/Zn-SOD from other fungi, including Aspergillus species.