Correlations between reduction–oxidation potential profiles and growth patterns of Saccharomyces cerevisiae during very-high-gravity fermentation

Lin, Yen‐Han; Chien, Wan-Shan; Duan, Kow‐Jen

doi:10.1016/j.procbio.2010.01.018

Cited by 44 publications

(35 citation statements)

References 8 publications

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“…Statistical experimental designs such as Plackett-Burman design for selection of critical nutrients and response surface methodology, which was based on a three-level four-factor BoxBehnken design for optimization of medium composition, were successfully employed for designing a low-cost VHG medium based on glucose [52]. Recently, correlations between reduction-oxidation potential proWles, which were controlled at certain levels by manipulating aeration, and the growth patterns of Saccharomyces cerevisiae during VHG fermentation were studied [38]. The results indicate that redox potential proWles are useful to pick up subtle diVerences as yeasts transition from one phase to another; thereby proper substrate feeding and/or product recovery strategies could be developed to maximize ethanol productivity and to process automation.…”

Section: Process Optimization Studiesmentioning

confidence: 99%

Very high gravity (VHG) ethanolic brewing and fermentation: a research update

Puligundla

Šmogrovičová

Obulam

et al. 2011

J Ind Microbiol Biotechnol

175

109

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There have been numerous developments in ethanol fermentation technology since the beginning of the new millennium as ethanol has become an immediate viable alternative to fast-depleting crude reserves as well as increasing concerns over environmental pollution. Nowadays, although most research efforts are focused on the conversion of cheap cellulosic substrates to ethanol, methods that are cost-competitive with gasoline production are still lacking. At the same time, the ethanol industry has engaged in implementing potential energy-saving, productivity and efficiency-maximizing technologies in existing production methods to become more viable. Very high gravity (VHG) fermentation is an emerging, versatile one among such technologies offering great savings in process water and energy requirements through fermentation of higher concentrations of sugar substrate and, therefore, increased final ethanol concentration in the medium. The technology also allows increased fermentation efficiency, without major alterations to existing facilities, by efficient utilization of fermentor space and elimination of known losses. This comprehensive research update on VHG technology is presented in two main sections, namely VHG brewing, wherein the effects of nutrients supplementation, yeast pitching rate, flavour compound synthesis and foam stability under increased wort gravities are discussed; and VHG bioethanol fermentation studies. In the latter section, aspects related to the role of osmoprotectants and nutrients in yeast stress reduction, substrates utilized/tested so far, including saccharide (glucose, sucrose, molasses, etc.) and starchy materials (wheat, corn, barley, oats, etc.), and mash viscosity issues in VHG bioethanol production are detailed. Thereafter, topics common to both areas such as process optimization studies, mutants and gene level studies, immobilized yeast applications, temperature effect, reserve carbohydrates profile in yeast, and economic aspects are discussed and future prospects are summarized.

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Section: Process Optimization Studiesmentioning

confidence: 99%

Very high gravity (VHG) ethanolic brewing and fermentation: a research update

Puligundla

Šmogrovičová

Obulam

et al. 2011

J Ind Microbiol Biotechnol

175

109

View full text Add to dashboard Cite

show abstract

“…The experimental procedure, equipment, sampling, and data analysis used in this article have been previously reported . Briefly, an industrial S. cerevisiae (Ethanol Red TM ) strain was precultured and then propagated in a jar fermenter under three different initial glucose concentrations (∼200, ∼250, and ∼300 g/L) and three redox potential control level: no control, −150 and −100 mV.…”

Section: Methodsmentioning

confidence: 99%

“…Among these models, iFF708 was the most referred and concise. As a result, iFF708 was adopted for this research and used to incorporate situations relating to ethanol production under redox potential–controlled VHG conditions . To do so, the following modifications to the original iFF708 model were made: (a) ETC and oxidative phosphorylation, (b) proton gradient and ATP synthesis, and (c) malate–aspartate shuttle.…”

Section: Methodsmentioning

confidence: 99%

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Metabolic flux analysis of Saccharomyces cerevisiae during redox potential–controlled very high‐gravity ethanol fermentation

Zhang

Lin

2020

Biotech and App Biochem

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A previously published genome‐scale metabolic model namely iFF708 was modified to depict the metabolic flux distribution within Saccharomyces cerevisiae grown under a redox potential–controlled very high‐gravity condition. The following modifications were made: electron transport chain (ETC) and oxidative phosphorylation, proton gradient and ATP transportation, and malate–aspartate shuttle. With these modifications, this model could describe the experimental data collected from the above‐mentioned ethanol fermentation. As a result, the simulation unveiled that the P/O ratio is critical under microaerobic conditions and the malate–aspartate shuttle is inactivated due to the shortage of electron transport across mitochondria. In other words, the limited supply of oxygen suppresses the functionality of oxidative phosphorylation, tricarboxylic acid (TCA) cycle, and ETC. In terms of the glycolytic pathway, fluxes coming from glucose‐6‐phosphate and pyruvate nodes are insensitive to the changes of fermentation redox potential. As the initial glucose concentration is greater than 250 g/L, the interactive effect between the initial glucose concentration and redox potential level becomes noticeable.

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“…For example, with addition of potassium ferrocyanide, CRP could be maintained between 280 and 80 mV [1] to obtain a high citric acid productivity in Aspergillus niger fermentation. In addition, CRP played an important role in the cellular physiology of microorganisms such as growth capacity [12,14,16] and thermal resistance [8,20]. However, there was no literature about the eVects of CRP on the production of biopolymers, such as -polylysine, poly( -D-glutamic acid), and PMLA.…”

Section: Introductionmentioning

confidence: 99%

Intensification of β-poly(l-malic acid) production by Aureobasidium pullulans ipe-1 in the late exponential growth phase

Cao

Luo

Zhao

et al. 2012

Journal of Industrial Microbiology and Biotechnology

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β-Poly(malic acid) (PMLA) has attracted industrial interest because this polyester can be used as a prodrug or for drug delivery systems. In PMLA production by Aureobasidium pullulans ipe-1, it was found that PLMA production was associated with cell growth in the early exponential growth phase and dissociated from cell growth in the late exponential growth phase. To enhance PMLA production in the late phase, different fermentation modes and strategies for controlling culture redox potential (CRP) were studied. The results showed that high concentrations of produced PMLA (above 40 g/l) not only inhibited PMLA production, but also was detrimental to cell growth. Moreover, when CRP increased from 57 to 100 mV in the late exponential growth phase, the lack of reducing power in the broth also decreased PMLA productivity. PMLA productivity could be enhanced by repeated-batch culture to maintain cell growth in the exponential growth phase, or by cell-recycle culture with membrane to remove the produced PMLA, or by maintaining CRP below 70 mV no matter which kind of fermentation mode was adopted. Repeated-batch culture afforded a high PMLA concentration (up to 63.2 g/l) with a productivity of 1.15 g l(-1) h(-1). Cell-recycle culture also confirmed that PMLA production by the strain ipe-1 was associated with cell growth.

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Correlations between reduction–oxidation potential profiles and growth patterns of Saccharomyces cerevisiae during very-high-gravity fermentation

Cited by 44 publications

References 8 publications

Very high gravity (VHG) ethanolic brewing and fermentation: a research update

Very high gravity (VHG) ethanolic brewing and fermentation: a research update

Metabolic flux analysis of Saccharomyces cerevisiae during redox potential–controlled very high‐gravity ethanol fermentation

Intensification of β-poly(l-malic acid) production by Aureobasidium pullulans ipe-1 in the late exponential growth phase

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