Quantification of oxidative stress in Saccharomyces pastorianus propagation: Gene expression analysis using quantitative reverse transcription polymerase chain reaction and flow cytometry

Beugholt, Alexander; Büchner, Kai; Geier, Dominik; Becker, Thomas

doi:10.3389/fceng.2022.1035348

Cited by 3 publications

(3 citation statements)

References 27 publications

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“…These primers were then synthesized by TIB Molbiol Syntheselabor GmbH (Berlin), and their sequences are available in Tables S2 and S3. † As housekeeping genes, KRE11, UBC6, and TAF10 were used for their stability and consistent expression, making them suitable as references for normalizing the target gene expression levels, as reported by Beugholt et al 36 During qPCR measurements, a 10 μL final volume was used containing 0.7 μL of DNA template, 0.4 μL of each respective primer, 5 μL of SybrGreen (Biozym), and 3.5 μL of RNase-free water.…”

Section: G Quantitative Polymerase Chain Reaction (Qpcr) For Gene Exp...mentioning

confidence: 99%

“…These primers were then synthesized by TIB Molbiol Syntheselabor GmbH (Berlin), and their sequences are available in Tables S2 and S3 †. As housekeeping genes, KRE11, UBC6, and TAF10 were used for their stability and consistent expression, making them suitable as references for normalizing the target gene expression levels, as reported by Beugholt et al 36…”

Section: Device Design and Fabricationmentioning

confidence: 99%

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Millifluidic magnetophoresis-based chip for age-specific fractionation: evaluating the impact of age on metabolomics and gene expression in yeast

Wittmann,

Eigenfeld,

Büchner

et al. 2024

Lab Chip

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Section: G Quantitative Polymerase Chain Reaction (Qpcr) For Gene Exp...mentioning

confidence: 99%

Section: Device Design and Fabricationmentioning

confidence: 99%

Millifluidic magnetophoresis-based chip for age-specific fractionation: evaluating the impact of age on metabolomics and gene expression in yeast

Wittmann,

Eigenfeld,

Büchner

et al. 2024

Lab Chip

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“…However, the industry requires individual and reproducible yeast propagation with high yields and stable product quality (Baghban et al, 2019;Rahmat and Kang, 2020). An integral part of this process is effective aeration to avoid potential oxygen limitations and to enable proper growth conditions without damaging the cells through oxidative stress (Beugholt et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Improvement of Saccharomyces propagation performance through oxygen-enriched air and aeration parameter variation

2023

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A variety of yeast applications in the food and beverage industry require individual and reproducible yeast propagation at high yields and consistent quality. One quality-determining parameter for yeast propagation is effective aeration to avoid oxygen depletion. Therefore, this work investigated three important aeration parameters: airflow, pulse time, and oxygen concentration, for their influence on yeast propagation. The aeration of a propagator involves phase transitions which are gradient-driven processes and can be accelerated with higher gradients between the liquid medium and the gas bubbles. In this study, oxygen-enriched air generated with membrane filters was used to aerate the system in an easy and cost-efficient way without the need for expensive technical gas usage. Propagation experiments were carried out in a pilot-scale reactor equipped with a membrane filter system for enhanced oxygen concentrations in ingas and online sensors for representative monitoring of the process. The membrane filter system is based on the separation of nitrogen in compressed air, leading to oxygen enrichment. Using oxygen-enriched air for propagation aeration showed higher oxygen transfer into the medium and the anaerobic process time caused by oxygen depletion due to high cell numbers was reduced by an average of 7.4% for pulsed aeration. Additionally, we conducted experiments with controlled measures of dissolved oxygen using different oxygen concentrations for aeration. The main objective of this study is to present a new and affordable optimization of propagation aeration using membrane filtration to enrich process air. The results showed increased cell counts for higher ingas oxygen concentrations and no negative impact on cell vitality was observed. Hence, our investigations showed that using oxygen-enriched air reduced the frequency of pulsed aeration, thus hindering foam formation, a limiting factor of the yeast propagation process.

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The role of yeast propagation aeration for subsequent primary fermentation with respect to performance and aroma development

Beugholt,

Geier,

Becker

2024

Int J of Food Sci Tech

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SummaryDuring the primary fermentation of beer, the yeast simultaneously carries out a series of processes such as cell growth, pH shift, and the formation and degradation of essential flavour components. Harvested yeast from a previous fermentation can be used to inoculate the fermentation or fresh cells can be produced through aerobic propagation. This study investigated the influence of different aeration conditions during Saccharomyces pastorianus ssp. carlsbergensis propagation on the cell count development and the production of secondary metabolites during the subsequent primary beer fermentation. Propagations were conducted by applying six different dissolved oxygen concentrations, and the cells were used as inoculum for the subsequent fermentation. Cell count, pH shift, and the development of key aroma compounds were monitored throughout the primary fermentation to evaluate any difference between the conducted fermentations. The outcomes revealed significant distinctions between fermentations using yeast propagated under elevated oxygen levels and those propagated under reduced oxygen levels. Cells propagated using lower oxygen concentrations showed earlier cell growth with 40% lower final cell counts, resulting in 50% reduced biomass yields. Additionally, lower oxygen concentrations during propagation led to lower pH shifts during primary fermentation with 20% more higher alcohols and elevated formation of acetaldehyde, and esters.

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Quantification of oxidative stress in Saccharomyces pastorianus propagation: Gene expression analysis using quantitative reverse transcription polymerase chain reaction and flow cytometry

Cited by 3 publications

References 27 publications

Millifluidic magnetophoresis-based chip for age-specific fractionation: evaluating the impact of age on metabolomics and gene expression in yeast

Millifluidic magnetophoresis-based chip for age-specific fractionation: evaluating the impact of age on metabolomics and gene expression in yeast

Improvement of Saccharomyces propagation performance through oxygen-enriched air and aeration parameter variation

The role of yeast propagation aeration for subsequent primary fermentation with respect to performance and aroma development

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