There is few data in the literature on Eisenia fetida bimass concentrations of such elements as phosphorus, abundant in municipal sewage sludge or sodium which in considerable amounts is found in tannery sludge. The paper aimed to determine the contents of selected elements (Ca, Mg, Na, K, P and Cr) in Eisenia fetida redworm kept in sewage sludge composts. The studied composts were characterised by diversified contents of the analysed elements. Their concentrations in the redworm biomass depended on their contents in composts. Bigger concentrations of calcium, sodium and chromium in the redworm biomass were found in specimens feeding in composts with added tannery sludge. Redworm originating from composts prepared from municipal sludge contained more phosphorus. Magnesium and potassium contents in the redworm biomass from different composts were comparable, which resulted from their similar contents in composts.

The aim of the study was to obtain Fil^- mutants (unable to transform from yeast cells to filamentous forms) of Y. lipolytica A-101-1.31 strain induced by UV irradiation. Previous studies suggest that such mutants can be more effective and stable during continuous CA production. At 20% UV survival level of cells, Fil^- mutants frequency was 0.35%. The total 15 smooth colony forming mutants were isolated on YM agar but only 7 of them characterized by good stability; the Fil⁺ revertants did not appear during culturing up to 45 generation. The acet^- mutation in those strains responsible for high citrate fermentation purity was well sustained. Assimilation profiles of different carbon sources were identical that those showed by parent strains. Only one of mutants produced CA as efficiently as the parent strain.

The production of citric acid from glucose syrup by acetate mutant strain of Y. lipolytica K-1 in the membrane reactor with using continuous yeasts recycling by microfliltration module was examined. Citrate production rates and yields achieved in the Continuous Membrane Stirred Tank Reactor were dependent on composition of the feed medium. Experiments in CMSTR have shown that presence of yeast extract in the feed medium (0,2 gL^-1) is the most suitable for both citric acid production and stability of the continuous process with smooth strain of K-1. The volumetric citric acid production rate (Q_CA) obtained in CMSTR with high biomass concentration ranged from 1,1 to 1,2 gL^-1h^-1.

Citric acid production from sucrose by single and mixed cultures of Y. lipolytica immobilized in carrageenan gels beads were investigated in repeated batch culture. The best results were obtained for 2% carrageenan gel beads containing 15% of biomass. The use of gels treated with glutaraldehyde containing mixed cultures of Suc^- and Suc⁺ (both in ratio 2:1 and 3:1) gave the highest level of citric acid during the fifth 7-day batch. The repeated batch cultures with free cells were more efficiency than with immobilized cells, because achieved both higher citric acid concentration and yield.

Biomass of Y. lipolytica A-101 yeast obtained from crude repeseed oil has been spray-dried in the range of temperature from 115ºC to 200ºC. Amount of viable cells decreased with temperature increase. Residual substrate played role of protective agent. The biomass contained 51,2% of protein with high biological value of 80% and 8,9% intracellular lipids with high level unsaturated fatty acids about 90%.

The thermal death kinetics of 6 yeast strains: Candida famata AII4b and MI1a, C. sphaerica BI6c and FII7a, C. kefyr PII1b and C. lipolytica PII6a, selected as costarters for cheese making, was investigated. The experiment was curried out in milk at 40ºC, 45ºC, 50ºC and pH 4.7 and 6.6. The yeasts showed little survival at 50ºC; the D₅₀ values ranged from 4–6 min for Candida famata strains to 9–16 min for other strains. At temperature 40ºC and 45ºC the rates of viable cells degradation were significantly lower. The most resistant strains were: C. sphaerica BI6c, C. sphaerica FII7a and C. kefyr PII1b having both D₄₀ and D₄₅ values as high as ≥ 90 min.

The aim of the work was to estimate the sporulation ability of the fusants in comparison with the parental strains. Biological material was composed of: Schwanniomyces occidentalis ATCC 48086(1), Saccharomyces cerevisiae V30 (2), Saccharomyces cerevisiae D43 (3), Saccharomyces cerevisiae „malt” (4), Saccharomyces diastaticus ATCC 13007 (5), and their fusion products: R1, R4 (1x2), S2, S3 (1x5), P1, P4 (1x3), 5.1 (1x4). Sporulation test was conducted on Mc’ Clary’s medium with agar. Four out of seven hybrids were able to sporulate. Two fusants: S2, S3 sporulated similar to Saccharomyces sp. and hybrids P1 and P4 similar to Schwanniomyces sp.

The aim of the work was to estimate the ability of the fusants and the parental strains to assimilate different carbon source. Biological material was composed of: Schwanniomyces occidentalis ATCC 48086 (1), Saccharomyces cerevisiae V30 (2), Saccharomyces cerevisiae D43 (3), Saccharomyces cerevisiae „malt” (4), Saccharomyces diastaticus ATCC 13007 (5), and their fusion products: R1, R4 (1x2), P1, P4 (1x3), 5.1 (1x4) S2, S3 (1x5). Hybrids obtained after protoplast fusion of parental strains were able to assimilate new carbon source in comparison with Saccharomyces sp.

The proteolytic activity of 7 yeast strains belonging to species Candida famata, C. sphaerica, C. intermedia, C. kefyr, Geotrichum penicillatum, Yarrowia lipolytica i Saccharomyces kluyveri were determined. It was shown big variations in the level of activity especially of extracellular proteases of yeasts. The most active were extra- and intracellular proteases of strain Y. lipolytica PII6a. Caseinolytic proteases of all strains were inhibited by PMSF and DFP. Majority of them exhibited optimum at pH 6.5–7.5. Extracellular proteases of yeasts active against hemoglobin had optimum at pH 3.5–4.0.

Enzymatic activities (extra- and intracellular) of two strains of Yarrowia lipolytica yeast: A-101 and W29, originating from soil of different locations, were analysed by API-ZYM test. Additionally the lipolytic activity of these strains was compared. This activity was investigated by diffusion test on Spirit Blue Agar at different temperature (25 and 4ºC) and water activity (a_w: 0.99; 0.97; 0.93) and by measuring the free fatty acids liberation during growth of both strains on butter fat. Both strains appeared to be similar in their enzyme profiles and had a capability to grow on butter and to release preferencially of oleic acid from milk fat.

Biological process of degradation of formaldehyde and its derivatives present in furniture industry wastewater was studied. A biocenosis consisting of bacterial autochthonous microorganisms and methylotrophic yeast was constructed. It was shown that the introduction of methylotrophs into toxic wastewater enabled the development of organic life and the efficient biodegradation of various organic contaminants. The idea of generating active microbial community based on mixed pro- and eukaryotic biocenoses was proposed. Such a community could be applied to treat industrial wastewater containing lethal formaldehyde concentrations.

The aim of work was to determine the influence of Triticale malts and type of fermentation on physicochemical and sensorical features of beers. In laboratory scale, beers with 20, 40 and 100% use of Triticale malt was obtained. It was shown that viscosity of beers increased along with growth of use of Triticale malt. Top fermented beers had higher acidity, two times lower CO₂ content and shorter time of foam stability. During sensory analysis they were evalueted worse than bottom fermented beers. The best beer, irrespective of type of fermentation, was that with 20% of Triticale malt.

The endoxylanase from Aspergillus niger IBT-90 with the specific activity of 21.3 U/mg protein was used for improvement of wheat-rye and whole-meal bread. The addition of this xylanase in the range 500–1000 U/kg flour resulted in improvement of kneading and increase of loaf volume in the case of kinds of bread. This dough supplementation caused better crumb porosity and higher moisture in bread and finally the shelf life is extended. No increase of total acidity was resulted from the enzyme addition. The experimental results have confirmed the applicability of this xylanase in bakery.