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Physiological tests for yeast brewery cells immobilized on modified chamotte carrier.

Berlowska J, Kregiel D, Ambroziak W - Antonie Van Leeuwenhoek (2013)

Bottom Line: The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures.Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain.This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Fermentation Technology and Microbiology, Technical University of Lodz, ul. Wolczanska 171/173, 90-924, Lodz, Poland, joanna.berlowska@p.lodz.pl.

ABSTRACT
In this study yeast cell physiological activity was assessed on the basis of the in situ activity of two important enzymes, succinate dehydrogenase and pyruvate decarboxylase. FUN1 dye bioconversion and cellular ATP content were also taken as important indicators of yeast cell activity. The study was conducted on six brewing yeast strains, which were either free cells or immobilized on a chamotte carrier. The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures. Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain. However, in a comparative assessment of the fermentation process, conducted with the use of free and immobilized cells, much more favorable dynamics and carbon dioxide productivity were observed in immobilized cells, especially in the case of brewing lager yeast strains. This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.

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FUN 1 staining. a Stationary phase, b after adhesion, c 7-day fermentation
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Fig3: FUN 1 staining. a Stationary phase, b after adhesion, c 7-day fermentation

Mentions: The metabolic activity (defined as the ability to fluorochrome bioconversion) of yeast strains was made visible using FUN1 stain. An enzyme activity assay and ATP determination of immobilized cells were conducted using more than one carrier. So the average value characterized the whole population. A large number of yeast cells with low enzyme activity were capable of bioconverting FUN1. Therefore, fluorescence staining revealed the diversity of metabolic activity in immobilized yeast cells (Fig. 3). This fact suggests an absence of physiological homogeneity in these populations.Fig. 3


Physiological tests for yeast brewery cells immobilized on modified chamotte carrier.

Berlowska J, Kregiel D, Ambroziak W - Antonie Van Leeuwenhoek (2013)

FUN 1 staining. a Stationary phase, b after adhesion, c 7-day fermentation
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3824387&req=5

Fig3: FUN 1 staining. a Stationary phase, b after adhesion, c 7-day fermentation
Mentions: The metabolic activity (defined as the ability to fluorochrome bioconversion) of yeast strains was made visible using FUN1 stain. An enzyme activity assay and ATP determination of immobilized cells were conducted using more than one carrier. So the average value characterized the whole population. A large number of yeast cells with low enzyme activity were capable of bioconverting FUN1. Therefore, fluorescence staining revealed the diversity of metabolic activity in immobilized yeast cells (Fig. 3). This fact suggests an absence of physiological homogeneity in these populations.Fig. 3

Bottom Line: The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures.Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain.This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Fermentation Technology and Microbiology, Technical University of Lodz, ul. Wolczanska 171/173, 90-924, Lodz, Poland, joanna.berlowska@p.lodz.pl.

ABSTRACT
In this study yeast cell physiological activity was assessed on the basis of the in situ activity of two important enzymes, succinate dehydrogenase and pyruvate decarboxylase. FUN1 dye bioconversion and cellular ATP content were also taken as important indicators of yeast cell activity. The study was conducted on six brewing yeast strains, which were either free cells or immobilized on a chamotte carrier. The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures. Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain. However, in a comparative assessment of the fermentation process, conducted with the use of free and immobilized cells, much more favorable dynamics and carbon dioxide productivity were observed in immobilized cells, especially in the case of brewing lager yeast strains. This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.

Show MeSH
Related in: MedlinePlus