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With rapid development of transport industry, there is a need for new sustainable energy sources. One solution is the production of ethanol from biomass (second generation biofuel). The search for effective, profitable technology of production and cheap raw materials selection, such as lignocelluloses complex, is necessary. Optimization of bioethanol production from lignocellulose makes it possible to obtain cheap, good quality fuel.
Synthetic polymers are important in many branches of industry, for example in the packaging industry. However, they have an undesirable influence on the environment and cause problems with waste deposition and utilization. Thus, there is a tendency to substitute such polymers with polymers that undergo biodegradable processes. Increasing interest in applying polymers based on natural materials such as starch has been observed. This review describes biodegradation processes of xenobiotics such as aromatic compounds, plastics (PVA, polyesters, polyethylene, and nylon), and polymer blends (Starch/Polyethylene, Starch/Polyester, and Starch/PVA). Moreover, this review includes information about biodegradable polymers such as mixtures of synthetic polymers and substances that are easy digestible by microorganisms (chemically modified starch, starch-polymer composites, thermoplastic starch, and biodegradable packing materials), synthetic materials with groups susceptible to hydrolytic microbial attack (polycaprolactone), and biopolyesters (poly-β-hydroxyalkanoates). Production of this kind of material and introducing it to the market is important for the natural environmental. It may result in decreasing the volume of waste dumps.
Microbiological contamination is a major problem for commercial fuel ethanol production in distilleries all over the world. Undesirable microorganisms compete with yeasts for nutritional substances; moreover, they produce lactic and acetic acids that harm yeast cells. One of the sources of microbiological pollution in the fermentation process is raw materials (e.g. grains). It is important to find out what kind of microflora contaminate them, and new technologies should be developed to reduce this contamination. The aim of this work was to determine the total number of mesophilic bacteria, the number of lactic acid bacteria, anaerobic bacteria, moulds, and yeasts that occur in raw materials used in distilleries in Poland’s Wielkopolska region. Moreover, the numbers of these microorganisms in the sweet mash, in the sweet mash after 24 hours of fermentation, and after complete fermentation were counted. We decided to check out the microbiological state of raw materials and fermentation mashes because of the low bioethanol efficiency reached in these small ethanol plants. In all five distilleries, mesophilic bacteria, lactic acid bacteria, anaerobic bacteria, moulds, and yeasts occurred in grains. The level of contamination was relatively high. These groups of microorganisms were also present in the sweet mash, in the sweet mash after 24 hours of fermentation and after complete fermentation. The level of contamination was similar in all distilleries that use the same raw materials, and it was rather high. So the obtained results (relatively high raw material and fermentation mashe microbiological contamination) can explain the low ethanol efficiency found in all tested distilleries.
Background. Bacterial contamination is a major problem for commercial fuel ethanol production in distilleries all over the world. The contaminating microorganisms produce acetic and lactic acid that has a detrimental effect on fermentation efficiency. The aim of this work was to calculate the number of bacterial contaminants in some distilleries. Moreover, in this study it was signified what kind of bacteria contaminate ethanol production process. Material and methods. Grains were obtained from five distilleries from some regions in Poland, in this work hereafter referred to as α, β, γ, δ, and ε distilleries. Corn was the raw material in the α, β, and γ distilleries, triticale in δ distillery, and rye in the ε one. From these five distilleries, sweet mashes during fermentation and after it, were also analysed. The total number of microorganisms, the number of lactic acid bacteria, the number of anaerobic bacteria and the quantity of yeasts and moulds in raw materials were calculated. Results. The number of total viable bacteria (CFU/g), lactic acid bacteria (CFU/g), anaerobic bacteria (CFU/g), moulds, and yeasts (CFU/g) occur in the samples were determined. In all distilleries tested, all groups of microorganism were present. Conclusions. The results of our study show that all tested distilleries have a lot of difficulties with microbiology pollution which leads to a decrease of ethanol production and economical problems. From the economical point of view, reduction of microbial contamination makes it possible to increase the production volume
Produkty spożywcze stanowią nośnik dla bakterii oraz wirusów. W ostatnich latach, pomimo wzrastającej świadomości higienicznej ludzi, obserwujemy wzrost liczby zatruć pokarmowych. Przyczyną tego jest z jednej strony wzrost spożycia produktów gotowych, tzw. wygodnych, z drugiej zaś pojawianie się nowych patogenów w wyniku migracji ludności, a także wymiany towarów pomiędzy państwami całego świata. W pracy podjęto próbę scharakteryzowania zanieczyszczeń mikrobiologicznych z podziałem na produkty pochodzenia roślinnego oraz zwierzęcego. Przedstawiono również główne choroby przenoszone przez żywność, a także metody poprawy mikrobiologicznej jakości gotowych produktów spożywczych
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