Telepszámok szerepe az ivóvíz-szolgáltatásban = The role of colony count in water supply

Az ivóvíz az egyik legszigorúbban ellenőrzött élelmiszer, amelyre jellemző, hogy kémiai-fizikai tulajdonságai állandónak mondhatók, de biológiailag aktív közeg, amit a víziközmű üzemeltetők fertőtlenítéssel tudnak szabályozni. A kezelés hatékonyságának ellenőrzésében a fekális szennyeződést jelző baktériumok mellett az un. indikátor szervezeteknek is fontos szerepük van, így a telepszámnak is. A vizek általános mikrobiológiai jellemzésére használatos telepszám a 22°C és 37°Con tenyészthető baktériumok telepeinek összessége, amelynek szabvány szerinti vizsgálata az általános bakteriológiai fertőzöttségre jellemző mennyiségi információt ad az üzemeltetőnek. Célunk az volt, hogy megismerjük a Fővárosi Vízművek Zrt. termelési és szolgáltatási területén előforduló mikroorganizmusokat és klóralapú fertőtlenítőszerrel szembeni rezisztenciájukat. Eredményeink alapján az azonosított baktériumok vizes rendszerekben gyakran előforduló, biofilm alkotó, egészségre nem káros szervezeteknek bizonyultak. Mindezek mellett a hálózatban alkalmazott klórozáshoz képest csak több tízszeres klórkoncentráció esetén értünk el hatékony fertőtlenítést a termelési területekről izolált törzsek esetén. Drinking water is one of the most strictly controlled foods, characterized by the fact that its chemical and physical properties are by and large stable, but it is a biologically active medium, which is controlled by water companies using disinfection. In addition to bacteria indicating fecal contamination, so-called indicator organisms, such as colony counts, also play an important role in checking the efficiency of the treatment. Colony counts used for the general microbiological characterization of waters are the number of colonies of bacteria culturable at 22 and 37 °C, and their testing according to the standard provides the operator with quantitative information about general bacteriological contamination. Our goal was to identify microorganisms occurring in the production and service areas of the Waterworks of Budapest, and also their resistance to chlorine-basaed disinfectants. Based on our results, the bacteria identified are biofilm-forming organisms not harmful to health that commonly occur in aqueous systems. However, in case of strains isolated from production areas, efficient disinfection was only achieved by using chlorine concentrations several tens of times higher than that applied during chlorination of the supply network

Β-glucosidase production of two different Aspergillus strains

Β-glucosidase has an important role in cellulose degradation by cleaving the cellobiose to glucose units. Supplementation of Trichodermacellulase with exogenous β-glucosidase is needed to prevent the inhibition effect of cellobiose on exoglucanases and endoglucanases.Production of β-glucosidase by Aspergillus niger and Aspergillus phoenicishas been investigated under different fermentations. Both strains were appropriate for enzyme production at high level under the applied conditions. Cultivation of A. phoenicison Mandels' medium containing a complex nitrogen source has resulted in a higher β-glucosidase activity than on Vogel's medium. In an air-lift fermenter A. phoenicis grew in the shape of beads with 1.41 IU g–1 cell-associated enzyme activity. The fungal pellets can be used as in situ immobilized enzyme preparation. A. niger produced extracellular β-glucosidase at the level of 2.1 IU ml–1 in stirred-tank fermenter with a yield of 210 IU g–1 glucose and productivity of 21.8 IU l–1 h–1

Minor additions of Sn suppress the omega phase formation in beta titanium alloys

A critical characteristic of β-Ti alloys is the inevitable formation of ω-precipitates during certain heat treatments which leads to embrittlement, or even to a complete loss of ductility. Therefore, alloy design with the goal to inhibit the elementary ω-formation process is of utmost importance. Here, we propose a design strategy for prototypical β-type Ti–Cr–(Mo) alloys to alleviate this problem using only minor additions of Sn. Upon addition of Sn, we observed an extensive deceleration or even suppression of the ω-formation kinetics during isothermal ageing. Furthermore, the internal friction response of the elementary formation process indicated a decisive reduction of potential ω-nucleation sites, while the activation energy of the process remained almost unchanged. The results show, that the addition of Sn can significantly increase the width of the time–temperature process window and the long-time ageing resistance of β-Ti alloys, opening up huge opportunities for advanced alloy design and manufacturing routes.</p

Zeitwohlstand für Pflegekräfte als Potenzial für eine nachhaltige Gesellschaft

Seit vielen Jahren steht die Überlastung des Gesundheitssystems und insbesondere der Pflege in der Kritik. Zunehmend rücken auch die damit zusammenhängenden ökologischen Auswirkungen in den Fokus. Welche konkreten Maßnahmen gibt es, die den Zeitdruck des Personals im Gesundheitsbereich reduzieren und damit Potenziale für eine nachhaltige Lebensführung bieten

Growth and hydrolase profiles can be used as characteristics to distinguish Aspergillus niger and other black aspergilli

Wild type Aspergillus niger isolates from different biotopes from all over the world were compared to each other and to the type strains of other black Aspergillus species with respect to growth and extracellular enzyme profiles. The origin of the A. niger isolate did not result in differences in growth profile with respect to monomeric or polymeric carbon sources. Differences were observed in the growth rate of the A. niger isolates, but these were observed on all carbon sources and not specific for a particular carbon source. In contrast, carbon source specific differences were observed between the different species. Aspergillus brasiliensis is the only species able to grow on D-galactose, and A. aculeatus had significantly better growth on Locus Bean gum than the other species. Only small differences were found in the extracellular enzyme profile of the A. niger isolates during growth on wheat bran, while large differences were observed in the profiles of the different black aspergilli. In addition, differences were observed in temperature profiles between the black Aspergillus species, but not between the A. niger isolates, demonstrating no isolate-specific adaptations to the environment

Fractionation of cellulase and beta-glucosidase in a Trichoderma reesei culture liquid by use of two-phase partitioning

An aqueous two-phase system based on the two polymers poly(ethylene glycol) and dextran has been used for the fractionation of cellulase enzymes present in culture liquid obtained by fermentation with Trichoderma reesei. The activities of beta-glucosidase and glucanases were separated to high degree by using the two-phase systems for a counter-current distribution process in nine transfer steps. While the glucanases had high affinity to the poly(ethylene glycol) rich top phase the beta-glucosidase was enriched in the dextran-containing bottom phase. Multiple counter-current distribution performed indicates the heterogeneity of beta-glucosidase activities assuming at least four isoenzyme forms. One step concentration of beta-glucosidase by using system with 46:1 phase volume ratio resulted in 16 times higher enzyme activity

Vertiefungsanalyse 1: Alternative Nutzungskonzepte – Sharing, Leasing und Wiederverwendung

neu formatierte Ausg. 201

Use of hemicellulose hydrolysate for beta-glucosidase fermentation

Hydrolysis of cellulose by Trichoderma cellulases often results in a mixture of glucose, cellobiose, and low-mol-wt cellodextrins. Cellobiose is nonfermentable for most yeasts, and therefore it has to be hydrolyzed to glucose by beta-glucosidase prior to ethanol fermentation. In the present study, the beta-glucosidase production of one Penicillium and three Aspergillus strains, which were previously selected out of 24 strains, was investigated on steam pretreated willow. Both steam-pretreated willow and hemicellulose hydrolysate, released during steam explosion of willow, were used as carbon sources. Reference cultivation runs were performed using prehydrolyzed Solka Flee and glucose. The four strains were compared with Trichoderma reesei regarding sugar consumption and beta-glucosidase production. Aspergillus niger and Aspergillus phoenicis proved to be the best enzyme producers on hemicellulose hydrolysate. The maximum beta-glucosidase activity, 4.60 IU/mL, was obtained when A. phoenicis was cultivated on the mixture of hemicellulose hydrolysate and steam-pretreated willow. The maximum yield of enzyme activity, 502 IU/g total carbohydrate, was obtained when Aspergillus foetidus was cultivated on the hemicellulose hydrolysate