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Cold-active catalase (CAT) elicits great interest because of its vast prospective at the medical, commercial, and biotechnological levels. The study paper reports the production of cold-active CAT by the strain Penicillium griseofulvum P29 isolated from Antarctic soil. Improved enzyme production was achieved by optimization of medium and culture conditions. Maximum CAT was demonstrated under low glucose content (2%), 10% inoculum size, temperature 20°C, and dissolved oxygen concentration (DO) 40%. An effective laboratory technology based on changing the oxidative stress level through an increase of DO in the bioreactor was developed. The used strategy resulted in a 1.7- and 1.4-fold enhanced total enzyme activity and maximum enzyme productivity. The enzyme was purified and characterized. P. griseofulvum P29 CAT was most active at approximately 20°C and pH 6.0. Its thermostability was in the range between 5°C and 40°C.

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.

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.

A novel thermostable MnSOD was purified to electrophoretic homogeneity from the fungal strain Humicola lutea 110. The preparation of the pure metalloenzyme was performed using treatment with acetone followed by ion exchange and gel permeation chromatography. We found that the activity of this enzyme comprises about 80% of the total superoxide dismutase activity in the crude extract, containing two proteins: MnSOD and Cu/ZnSOD. The MnSOD has a molecular mass of approximately 76 kDa and 7200 U/mg protein specific activity. It is a tetrameric enzyme with four identical subunits of 18 860 Da each as indicated by SDS-PAGE, amino acid analysis and mass spectrometry. N-terminal sequence analysis of MnSOD from the fungal strain revealed a high degree of structural homology with enzymes from other eukaryotic sources. Physicochemical properties were determined by absorption spectroscopy and circular dichroism measurements. The UV absorption spectrum was typical for an MnSOD enzyme, but displayed an increased absorption in the 280 nm region (epsilon280 = 10.4 mM(-1). cm(-1)), attributed to aromatic amino acid residues. The CD data show that MnSOD has two negative Cotton effects at 208 and 222 nm allowing the calculation of its helical content. The ellipticity at 222 nm is 6800 deg. x m(2) x dmol(-1) and thus similar to the values reported for other MnSODs. The MnSOD from H. lutea 110 is stable over a wide range of pH (4.5-8), even in the presence of EDTA. The enzyme is thermostable at 70-75 degrees C, and more stable than MnSODs from other sources.