Maintaining yeast viability in continuous primary beer fermentation

Continuous fermentation is a long known and vastly studied process. The use of immobilized cell technology (ICT) is exploited in a significant number of studies owing to the associated high volumetric productivity, time savings and low capital demand. This work was aimed at solving one of the most relevant obstacles to implementing ICT on a large scale in beer fermentations, namely the control of biomass and the maintenance of cell viability in a gas-lift bioreactor. For this purpose, foam fractionation by skimming was proposed as a tool for control of continuous biomass concentration. The consequences of foaming on lignocellulosic yeast carrier losses were assessed and discussed. A steady consumption of sugars from wort, as well as consistent ethanol production, were achieved. The viability of the suspended cells in the reactor was compared with that of the cell population in the foam using flow cytometry. Results suggest that foam might be used as a promising tool to skim non-viable biomass out of the gas-lift reactor, thus ensuring the maintenance of a cell culture with optimum viability. Copyright © 2014 The Institute of Brewing & DistillingEduardo Pires gratefully acknowledges the Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) for PhD fellowship support (SFRH/BD/61777/2009) and Cristina Ribeiro from the Centre of Molecular and Environmental Biology/Department of Biology for technical support. This work was also supported by FEDER through POFC - COMPETE and by national funds from FCT through the project PEst-C/BIA/UI4050/2011. The materials supplied by UNICER Bebidas, S.A. (S. Mamede de Infesta, Portugal) are gratefully acknowledged. The financial contributions of the EU FP7 project EcoBioCAP - Ecoefficient Biodegradable Composite Advanced Packaging, grant agreement no. 265669 as well as of the Grant Agency of the Czech Republic (project GACR P503/12/1424) are also gratefully acknowledged

The impact of process parameters on flavour profile of alcohol-free beer from a single-stage continuous gas-lift reactor with immobilized yeast

In order to study the formation and conversion of the most important flavour compounds, the real wort used in alcohol-free beer fermentation was mimicked by a complex model medium containing glucose, yeast extract and aldehydes (hexanal, 2-methyl propanal, 3-methyl butanal, furfural). Fermentation experiments were carried out in a continuously operating gaslift reactor with brewing yeast immobilized on spent grains. During continuous experiment, parameters such as oxygen supply, residence time (Rt) and temperature (T) were changed to find the optimal conditions for alcohol-free beer production. The formation of ethanol, higher alcohols (HA), esters (ES), reduction of aldehydes, and consumption of glucose were observed. The results suggest that the process parameters, particularly the oxygen supply, represent a powerful tool in controlling the degree of fermentation and flavour formation carried out by immobilized biocatalyst. Under optimal conditions in the continuous immobilized cell reactor it was possible obtain a fermented model medium with a composition approaching commercial alcohol-free beers.Grant Agency of the Czech Republic - Project 104/06/1418

A területi kohézió történelmi áttekintése = The evolution of the territorial cohesion

Discussions about the territorial cohesion form part of the EU policy agendas since 1990. In relation to the accession processes, there is an increasing focus on the European spatial development. The new member states have different development potentials which resulted big inequalities within the whole European Union. These inequalities have always been present, and they are still today, economically and socially as well. Regarding the smaller spatial units, there are further differences. The increasing spatial inequalities pose further threats; therefore, they must be mitigated for the sustainable development of the European Union. Cohesion is already an integrated part of the common EU policies. It consists of three dimensions, which are economic, social, and spatial cohesion. The latest is one of the main EU objectives and determinant for the regional and cohesion policy since the ratification of the Lisbon Treaty. The purpose of this paper is to summarize and present the evolution of spatial cohesion based on EU documents and the literature

Fermentação primária da cerveja em contínuo : cinética de imobilização da levedura e qualidade do produto

A one stage continuous primary beer fermentation consisting of brewing yeast immobilized on spent grain particles in a gas lift reactor was studied. The goal of this work was to adjust the flavor of the continuously produced green beer to the desired character by sparging an adequate amount of air and by controlling the fermentation temperature in the immobilized yeast reactor as well as to predict the rate of the brewing yeast immobilization using a kinetic model adapted to the conditions of beer fermentation. The volumetric productivity of the continuous system was approximately 5 times higher than of the batch fermentation. The aroma profile of green beer from the continuous immobilized fermentation, run at zero air flow and temperatures 13 16°C, was fully comparable to that produced by industrial batch technology. Generally, the diacetyl concentration in green beer from the continuous fermentation was higher than in batch process, however, its re-assimilation was enhanced by high total biomass concentration in the system.Foi estudada a fermentação primária em contínuo da cerveja num reactor “gas-lift” com a levedura imobilizada em “drêches”. O objectivo do trabalho foi optimizar as características organolépticas da cerveja verde produzida em contínuo através do controle do caudal e composição do ar e da temperatura. Pretendeu-se também prever a velocidade de imobilização de levedura cervejeira sendo, para tal, desenvolvido um modelo adaptado às condições de fermentação. A produtividade volumétrica do sistema contínuo foi cerca de 5 vezes superior à obtida em descontínuo. O perfil aromático da cerveja verde produzida em contínuo, utilizando um caudal nulo de ar e temperaturas entre os 13 e os 16º C, foi comparável ao perfil aromático da cerveja produzida em descontínuo, numa unidade industrial. Na generalidade das situações testadas, a concentração de diacetilo na cerveja verde obtida em contínuo foi maior que no processo descontínuo sendo a sua reassimilação aumentada pela maior concentração de biomassa no sistema contínuo.Fundação para a Ciência e a Tecnologia (FCT)

Continuous immobilized yeast reactor system for complete beer fermentation using spent grains and corncobs as carrier materials

Despite extensive research carried out in the last few decades, continuous beer fermentation has not yet managed to outperform the traditional batch technology. An industrial breakthrough in favour of continuous brewing using immobilized yeast could be expected only on achievement of the following process characteristics: simple design, low investment costs, flexible operation, effective process control and good product quality. The application of cheap carrier materials of by-product origin could significantly lower the investment costs of continuous fermentation systems. This work deals with a complete continuous beer fermentation system consisting of a main fermentation reactor (gas-lift) and a maturation reactor (packedbed) containing yeast immobilized on spent grains and corncobs, respectively. The suitability of cheap carrier materials for long-term continuous brewing was proved. It was found that by fine tuning of process parameters (residence time, aeration) it was possible to adjust the flavour profile of the final product. Consumers considered the continuously fermented beer to be of a regular quality. Analytical and sensorial profiles of both continuously and batch fermented beers were compared.(Fundação de Amparo a Pesquisa do Estado de São Paulo, Brazil (FAPESPFundação para a Ciência e a Tecnologia (FC

Design, synthesis and evaluation of heterocyclic compounds with potential antimicrobial activity I

Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Title of the thesis: Design, synthesis and evaluation of heterocyclic compounds with potential antimicrobial activity I Author: Michal Brányik Supervisor: doc. PharmDr. Jan Zitko, Ph.D. Consultant: PharmDr. Martin Juhás, Ph.D. Antimicrobial resistance is an ever-growing problem that occurs worldwide. Many bacterial strains develop the ability to resist the otherwise efficient substances, thus posing a serious threat for the future. Mycobacterium tuberculosis (Mtb), the source of tuberculosis, is no exception. Given that it is the leading cause of death due to a single pathogen, many efforts have been put into finding new active compounds. The substances synthesized as a part of this thesis are based on previously prepared substances with potential antimicrobial activity. The basic structure consists of 2-aminooxazole or 2-aminothiazole and substituted pyridine or pyrazine carboxamides. The structures were confirmed by the 1 H and 13 C NMR spectra, IR spectra and mass spectrometry. All the substances were tested for in vitro activity against eight bacterial strains (four gram-positive and four gram-negative) as well as eight fungal strains (four yeast and four fungi). We also...Univerzita Karlova, Farmaceutická fakulta v Hradci Králové Katedra farmaceutické chemie a farmaceutické analýzy Název diplomové práce: Návrh, syntéza a hodnocení heterocyklických látek s potenciální antimikrobní aktivitou I Řešitel: Michal Brányik Vedoucí diplomové práce: doc. PharmDr. Jan Zitko, Ph.D. Konzultant: PharmDr. Martin Juhás, Ph.D. Antimikrobiální rezistence je stále rostoucím celosvětovým problémem. Mnoho bakteriálních kmenů vykazuje rezistenci vůči doposud účinným sloučeninám a právě proto je stěžejní pokračovat v hledání nových účinných látek. Tento problém se nevyhýbá ani původci tuberkulózy, Mycobacterium tuberculosis. Právě toto onemocnění je dle statistik WHO nejčastější příčinou úmrtí, jenž je způsobeno jedním patogenem, a proto je věnováno velké úsilí vývoji nových léčiv. Látky navržené a připravené jako součást této diplomové práce strukturně vycházejí ze sloučenin obsahujících fragment 2-aminooxazolu (2-aminothiazolu) a substituovaných pyridinkarboxamidů a pyrazinkarboxamidů. Struktura sloučenin byla charakterizována 1 H a 13 C NMR spektry, IR spektry a hmotnostní spektrometrií. Takto bylo připraveno a popsáno 13 nových látek. U všech těchto látek byla testována jejich antimikrobiální aktivita na čtyřech grampozitivních a čtyřech gramnegativních kmenech bakterií, následně také...Katedra farmaceutické chemie a farmaceutické analýzyDepartment of Pharmaceutical Chemistry and Pharmaceutical AnalysisFaculty of Pharmacy in Hradec KrálovéFarmaceutická fakulta v Hradci Králov

Continuous beer fermentation with yeast immobilized on spent grains : the effect of operational conditions

Fundação para a Ciência e a Tecnologia (FCT) - SFRH / BPD / 3541 / 2000

Physicochemical and biochemical interactions in yeast immobilization by adhesion to a cellulose based support

An important quality of yeast cell wall is the ability to adhere to other cell walls or solid surfaces. This feature of yeast is responsible for technologically important phenomena such as flocculation at the end of beer fermentation and cell adhesion to immobilization supports e.g. spent grains, DEAE-cellulose etc. Physicochemical properties of yeast surfaces, e.g. hydrophobicity and surface charge, have a substantial impact on cell adhesion and flocculation. The interaction energies calculated according to DLVO theory and interfacial free energies were compared with yeast adhesion experiments carried out in continuous gaslift reactor. Four different brewing yeast strains (Saccharomyces cerevisiae) were tested for their adhesion onto spent grain particles. The role of physicochemical surface properties in cell-cell and cell-carrier interactions was evaluated by comparing the computed predictions with experimental results. In view of the somewhat contradictory results, the importance of specific biological interactions is outlined. Preliminary results on the presence of FLO 11 gene in studied yeast stains are presented.info:eu-repo/semantics/publishedVersio