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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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Related in: MedlinePlus

Chamotte surface: a native, b with immobilized cells
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Related In: Results  -  Collection


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Fig1: Chamotte surface: a native, b with immobilized cells

Mentions: For the purposes of the present study, six brewing yeast strains were immobilized on chamotte carriers with chemically modified surfaces (Fig. 1a). The number of cells per carrier was assayed fluorometrically using DAPI. This cationic dye specifically binds to DNA in places rich in adenine–thymine pairs. It is also accumulated in small grooves of the DNA double helix (Barker and Smart 1996). According to the authors’ own research, the amount of emitted light, measured spectrofluorimetrically, is proportional to the number of stained, heat denatured, yeast cells. The effectiveness of the adhesion processes ranged from 2.6 to 4.0 × 107 cells per cm2. The spatial distribution of immobilized microorganisms was imaged using a scanning electron microscope HITACHI S-3000N (Fig. 1b).Fig. 1


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

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

Chamotte surface: a native, b with immobilized cells
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig1: Chamotte surface: a native, b with immobilized cells
Mentions: For the purposes of the present study, six brewing yeast strains were immobilized on chamotte carriers with chemically modified surfaces (Fig. 1a). The number of cells per carrier was assayed fluorometrically using DAPI. This cationic dye specifically binds to DNA in places rich in adenine–thymine pairs. It is also accumulated in small grooves of the DNA double helix (Barker and Smart 1996). According to the authors’ own research, the amount of emitted light, measured spectrofluorimetrically, is proportional to the number of stained, heat denatured, yeast cells. The effectiveness of the adhesion processes ranged from 2.6 to 4.0 × 107 cells per cm2. The spatial distribution of immobilized microorganisms was imaged using a scanning electron microscope HITACHI S-3000N (Fig. 1b).Fig. 1

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