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  • Author: Agata Markowska-Szczupak x
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The growth of Thermomyces lanuginosus (TSIKL.) isolates from garden composts and coffee beans on cellulose substrates and xylan at various water activity

Abstract

The study was to determine the effect of water activity (0.850; 0.900; 0.950; 0.995; and 0.999 aw) on the growth of T. lanuginosus on solid media containing different cellulose substrates (crystalline cellulose, carboxymethyl cellulose - CMC, fi lter paper, and sawdust) and xylan. The growth of isolates from coffee beans and garden composts were compared. All isolates did not grow on media with aw < 0.950. On media with aw > 0.950, the hydrolysis zones were only observed on xylan and CMC. The highest daily growth and hydrolysis zone rates were mostly obtained at 0.995 aw and the lowest values were observed at 0.950 aw. The coffee beans isolates at 0.950 aw had the CMC hydrolysis coeffi cient 1.7-times higher than that for xylan. The fungal growth (FG) coeffi cient data indicate that the coffee beans isolates were able to utilize CMC and crystalline cellulose for growth and the highest growth rate was obtained at 0.999 aw. Subsequently, the compost isolates were able to grow on all substrates but the highest growth rate was obtained on CMC at 0.950 and 0.999 aw. Thus, coffee beans and composts provide T. lanuginosus isolates with various growth and hydrolytic zone rates in the range of 0.950−0.999 aw.

Open access
A preliminary study on antifungal effect of TiO2-based paints in natural indoor light

A preliminary study on antifungal effect of TiO2-based paints in natural indoor light

The antifungal activity of four commercial photocatalytic paints (KEIM Ecosil ME, Titanium FA, Photo Silicate and Silicate D) in natural indoor light was investigated. The paints contained TiO2 in rutile and anatase crystalline forms as evidenced by means of the X-ray diffraction analysis. In most cases the paints inhibited growth of fungi viz. Trichoderma viride, Aspergillus niger, Coonemeria crustacea, Eurotium herbariorum, and Dactylomyces sp. The KEIM Ecosil ME paint displayed the highest antifungal effect in the light, which could be explained with the highest anatase content. The paint antifungal activity and the fungal sensitivity to the TiO2-mediated photocatalytic reaction both decreased in the following orders: KEIM Ecosil ME > Titanium FA > Photo Silicate > Silicate D and T. viride > Dactylomyces sp. > A. niger > E. herbariorum.

Open access
Relationships Between Fungal Contamination and Some Physicochemical Properties of Rapeseeds

Abstract

The aim of this study was to evaluate some properties of rapeseed, to determine the amount of fungi including thermotolerant and xerophilic species and to specify the correlations between some physical properties of rapeseed and the number of fungi. Material was 18 samples of rapeseeds. The characteristics of seeds included volumetric weight, impurities, pH, moisture, water activity, fat content, fat acidity and critical moisture of seeds. Number of fungi were investigated on RBA, YpSs, DG18 medium at 25, 37 and 45°C. Differences between amount of rapeseed impurities and fat acidity have been revealed. The number of fungi was diversified depending on medium and incubation temperature. The largest fungi number was isolated on DG18 at 25°C. Correlations between physicochemical properties of seeds and number of isolated fungi have been pointed out. Our study demonstrated that low pH values and weight by volume of seeds as well as high acidity of fat can be used as indicators of contamination of rapeseeds by fungi.

Open access
Influence of titanium dioxide modification on the antibacterial properties

Abstract

Antibacterial properties of 15 titania photocatalysts, mono- and dual-modified with nitrogen and carbon were examined. Amorphous TiO2, supplied by Azoty Group Chemical Factory Police S.A., was used as titania source (Ar-TiO2, C-TiO2, N-TiO2 and N,C-TiO2 calcined at 300°C, 400°C, 500°C, 600°C, 700°C). The disinfection ability was examined against Escherichia coli K12 under irradiation with UV and artificial sunlight and in dark conditions. It has been found the development of new photocatalysts with enhanced interaction ability with microorganisms might be a useful strategy to improve disinfection method conducted under artificial sunlight irradiation. The efficiency of disinfection process conducted under artificial sunlight irradiation with carbon (C-TiO2) and carbon/nitrogen (N,C-TiO2) photocatalysts was similar as obtained under UV irradiation. Furthermore, during dark incubation, any toxicity of the photocatalyst was noted.

Open access
Stability of selenium diet supplement

Abstract

Selenium is one of the trace elements playing a crucial role in a proper function of living organisms. Selenium intake varies, largely based on the selenium content of food. The daily Se intake recommended for adults amounts to 55 μg per day. The mean level of selenium in the population varies considerably between countries. Recent studies on the selenium dietary intakes in Poland showed that it is not sufficient to meet the daily requirement for this microelement so it is strongly recommended to employ selenium supplementation. The commercial product SEL-BRCA1® being a selenium diet supplement was subjected to chemical and microbial analysis to determine its stability in storage time and conditions. Basing on the obtained results it can be stated that the stability of studied supplement, stored in the closed bottles, can be confirmed for the period of time up to 45 months after the production date and it is not recommended to store opened bottles for the period of time longer than 12 months. The studied supplement showed a very high microbial stability what underscores its usefulness as human medicines.

Open access
The study of glycerol-based fermentation and broth downstream by nanofiltration

Abstract

In this work, the glycerol fermentation was carried out using Citrobacter freundii bacteria. The influence of glycerol and metabolites concentrations, and the pH changes on the efficiency of 1,3-propanediol production, during batch and fed-batch processes, was presented. The nanofiltration was used for the separation of obtained post-fermentation solutions. The resulted 1,3-PD solutions were significantly desalted, which may facilitate further downstream processes during 1,3-PD production.

Open access
On the characteristic and stability of iron diet supplements

Abstract

The iron diet supplements: AproFER 1000 and AproTHEM were subjected to various chemical, microbial and magnetic analysis. The microbial analysis revealed no presence of pathogenic bacteria in the studied products. No significant changes in iron content or forms (bivalent/trivalent) were observed in EPR analysis of supplements stored at different conditions for a long period of time. The chemical and magnetic analysis showed that both AproFER 1000 and AproTHEM contain a high concentration of bivalent iron so they can be used as an iron diet supplements.

Open access
Synthesis and antibacterial properties of Fe3O4-Ag nanostructures

Abstract

Superparamagnetic iron oxide nanoparticles were obtained in the polyethylene glycol environment. An effect of precipitation and drying temperatures on the size of the prepared nanoparticles was observed. Superparamagnetic iron oxide Fe3O4, around of 15 nm, was obtained at a precipitation temperature of 80°C and a drying temperature of 60°C. The presence of functional groups characteristic for a polyethylene glycol surfactant on the surface of nanoparticles was confirmed by FTIR and XPS measurements. Silver nanoparticles were introduced by the impregnation. Fe3O4-Ag nanostructure with bactericidal properties against Escherichia coli species was produced. Interesting magnetic properties of these materials may be helpful to separate the bactericidal agent from the solution.

Open access
Preparation, properties and potential applications of a photocurable varnish with pleasant limonene smell

Abstract

Photocurable materials which are obtained on the basis of urethane acrylate resins are often used in the industry for the production varnishes or protective coatings. The main disadvantage which is connected with the utilization of these varnishes is their unpleasant smell during the process of production and curing. This work presents the photocurable varnish which was obtained on the basis of aliphatic urethane acrylate and R-(+)-limonene. The utilization of this raw materials allows to obtain the smelling coatings. The aim of this work were the studies on the influence of limonene molecules on the mechanical properties of the UV-cured coatings. These studies showed that the coatings with limonene molecules retain their properties, and are characterized by the very good adhesion, cohesion and high gloss. These kinds of varnishes can be applied for preparation of appropriate protective coatings on the surface of wood, metals, and nail plates. These protective coatings have not only pleasure smell but also can have the bactericidal and fungicidal properties. The studies performed with Escherichia coli ATCC29425 and Candida albicans confirmed these properties.

Open access