Background. Bacterial contamination is an ongoing problem for commercial bioethanol plants. It concerns factories using grain and also other raw materials for ethanol fermentation. Bacteria compete with precious yeasts for sugar substrates and micronutrients, secrete lactic and acetic acids, which are toxic for yeast and this competition leads to significant decrease of bioethanol productivity. For this study, bacterial contamination of corn grain was examined. Then the grain was treated by ammonia solution to reduce microbial pollution and after that the microbiological purity of grain was tested one more time. Disinfected and non-disinfected corn grains were ground and fermentation process was performed. Microbiological purity of this process and ethanol yield was checked out. Material and methods. The grain was disinfected by ammonia solution for two weeks. Then the grain was milled and used as a raw material for the ethanol fermentation. The fermentation process was carried out in 500-ml Erlenmeyer flasks. Samples were withdrawn for analysis at 0, 24, 48, 72 hrs. The number of total viable bacteria, lactic acid bacteria, acetic acid bacteria, anaerobic bacteria and the quantity of yeasts and moulds were signified by plate method. Results. Ammonia solution effectively reduces bacterial contamination of corn grain. Mash from grain disinfected by ammonia contains less undesirable microorganisms than mash from crude grain. Moreover, ethanol yield from disinfected grain is at the highest level. Conclusions. The ammonia solution proved to be a good disinfection agent for grain used as a raw material for bioethanol fermentation process
This paper studies nitrogen oxide reduction by means of ammonia in a flow reactor with a fixed bed of the Polish carbon sorbent AKP-5. The kinetic curves (t), showing the dependence of the degree of reduction of nitrogen oxide on time have been determined for four inlet NO concentrations. On the basis of the degree of NO reduction determined for the steady state conditions, a simplified model of the kinetic equation has been developed and verified. The results obtained are very important for environmental protection.
The influence of an adsorbent bed height made of tree bark on ammonia emission reduction was investigated under two scenarios: for constant mass of adsorbent and for adsorbent mass as a function of bed height. In both cases, measurements were performed on adsorptive beds of comparable height; other experimental conditions are presented in the part of the paper dealing with research methodology. The choice of tree bark as adsorbent material has been dictated by the results of preliminary research that was conducted on other biodegradable adsorbents in order to fulfill the basic assumption, i.e. that such materials, saturated with ammonia, should serve as natural organic fertilizer in plant production. The amount of ammonia adsorbed on tree bark increased linearly with the increasing height of the adsorbent bed. These results were analyzed together with the data on reduced ammonia emissions, including the amount of adsorbed pollution and bed height. Moreover, the ratio of bed height to the adsorber inner diameter (h/d w) was used in data analysis. For the given optimal height of an adsorbent bed, the most appropriate time for replacing tree bark is when breakthrough first occurs.
Emisja amoniaku z nawozów naturalnych stanowi jedno z najważniejszych, rolniczych źródeł rozpraszania azotu i zanieczyszczania środowiska. Na uwagę zasługują też gazowe straty amoniaku, które mają miejsce podczas stosowania, zwłaszcza pogłównie, mineralnych nawozów azotowych zwierających amonowe i amidowe formy azotu. W łatach 2004-2005 doświadczalnie, z wykorzystaniem metod mikrometeorologicznej dozymetrii pasywnej, określano straty amoniaku podczas stosowania obornika bydlęcego pod uprawy polowe oraz gnojówki bydlęcej, saletry amonowej i mocznika, stosowanych pogłównie na użytkach zielonych. Wykazano, że straty azotu amoniakalnego z obornika zastosowanego w dawce 140 kg N·ha⁻¹, przykrytego glebą przed upływem doby od rozrzucenia, kształtują się na poziomie około 9,5% początkowej dawki azotu ogółem. Natomiast straty azotu z obornika zastosowanego w dawce 120 i 150 kg N·ha⁻¹ i przykrytego glebą po upływie trzeciej doby są ponaddwukrotnie większe i kształtują się na poziomie odpowiednio 20,7 i 27,6% zastosowanej dawki azotu ogółem. Najwyższe straty amoniaku, rzędu 49,5% azotu ogółem, zanotowano po zastosowaniu na łąkę trwałą gnojówki bydlęcej w dawce 92,5 kg N·ha⁻¹ i przy zastosowaniu rozbryzgowej techniki aplikacji. Natomiast zastosowanie na łące trwałej pod drugi pokos saletry amonowej lub mocznika w dawce 60 kg N·ha⁻¹ wiązało się ze stratami azotu amoniakalnego na poziomie 7,1% dla saletry amonowej i od 21,5 do 33,6% dla mocznika.
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VacA toxin is one of the most important virulence factors produced by H. pylori even though neither its role nor its action mechanisms are completely understood. First considered as a toxin inducing only cell vacuolation, VacA causes apoptosis of gastric epithelial cells by targeting mitochondria. A hotly debated question about VacA action is its relationship with ammonia, which is produced in vivo by H. pylori urease. While ammonia is strictly required for VacA-dependent vacuolation, its role in VacA-induced apoptosis is much less defined. This study was thus aimed to investigate the relationship between VacA toxin and ammonia in H. pylori-induced mitochondrial damage and apoptosis of human gastric epithelial cells in culture by means of flow cytometry. Our results show that, unlike cell vacuolation, in MKN 28 cells neither apoptosis nor dissipation of mitochondrial transmembrane potential induced by VacA require ammonia. Nevertheless, ammonia significantly potentiates both these VacA-induced effects, but independently of the swelling of VacA-containing endosomes (i.e., vacuolation). Our findings make unlikely the hypothesis that ammonia-dependent swelling and rupture of endosomal vesicles in which VacA is sequestered after cell internalization may allow the toxin to reach mitochondria and trigger apoptosis.
H. pylori ureA and ureB genes encoding both subunits of urease were expressed transgenically in a low-alkaloid line of tobacco (LA Burley 21). Analysis of transgene expression at both the mRNA and protein levels revealed a significant increase (up to 8-fold) in ammonia concentration correlated with an amount of UreB protein detected in the leaves, and an increase (up to 2-fold) in urease activity in transformants as compared to control plants.