Dissolved carbon dioxide concentration profiles during very-high-gravity ethanol fermentation

Srinivasan, S.; Feng, Sijing; Lin, Yen‐Han

doi:10.1016/j.bej.2012.07.019

Cited by 7 publications

(6 citation statements)

References 25 publications

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“…It is also important to note that there were no residual glucose left at each cycle for all sets of experiments. These conclusions were agreed with previous publications related to yeast metabolism [3,9]. …”

Section: Reproducibility Of Dco 2 -Driven Repeated Batch Fermentationsupporting

confidence: 94%

“…In order to make up for the gap of phenomenon of dissolved carbon dioxide in ethanol fermentation, a series of dissolved carbon dioxide monitoring and control experiments were designed and performed by our group. We reported dCO 2 concentration profiles during VHG fermentation [9] and has successfully incorporated a dCO 2 based control methodology to improve otherwise sluggish batch fermentation for glucose concentrations higher than 200 g/L. We hypothesized that the repeated batch operation of a fermenting system can run through SCF under both of with and without dissolved CO 2 control condition and result in higher ethanol productivity.…”

Section: Introductionmentioning

confidence: 98%

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Ethanol Fermentation Under Dissolved Carbon Dioxide Control

Feng

Lin

2014

Energy Procedia

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Dissolved carbon dioxide (dCO 2 ) evolved from Saccharomyces cerevisiae was measured, controlled and used to drive repeated batch operation for ethanol fermentation. The experiments were conducted at four glucose feeds (150, 200, 250 and 300 g/l) under three dCO 2 control levels (no control, 750 ppm and 1000 ppm). Results showed that the evolution patterns of dCO 2 depend on the extent of glucose being utilized as well as the dCO 2 control level. Repeated batch was successfully operated for four glucose feeds under dCO 2 control. Controlling dCO 2 level at 750 ppm, the self-cycling period for each repeated batch is 6.6±0.3, 7.3±0.2, 12.12±1.12, and 21.70±5.98 h, as glucose feed changes from 150, 200, 250 and 300 g/l, respectively. When dCO 2 level increases, the self-cycling period increases as well.

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Section: Reproducibility Of Dco 2 -Driven Repeated Batch Fermentationsupporting

confidence: 94%

Section: Introductionmentioning

confidence: 98%

Ethanol Fermentation Under Dissolved Carbon Dioxide Control

Feng

Lin

2014

Energy Procedia

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“…At high feed glucose concentrations, high inhibitory ethanol concentrations are observed only under VHG conditions. Ethanol concentrations over 40 gl −1 exert inhibition on yeast metabolism, and turns to toxicity if there is an excess in ethanol concentration up to about a 90 gl −1 [4].…”

Section: Ethanol Effectmentioning

confidence: 99%

“…On the other hand, at the end of the process, the very high final ethanol concentration inhibits yeast survival, giving a loss of cell viability. When ethanol concentration is over 40 gl −1 , it inhibits the yeast metabolism and when it exceeds 90 gl −1 it becomes toxic [4].…”

Section: Introductionmentioning

confidence: 99%

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Continuous Ethanol Fermentation at Very High Gravity in the Presence of <i>Saccharomyces cerevisiae</i>: A Bifurcation Analysis

Abdelghani¹

2018

JSBS

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In this paper, a study of the bifurcation analysis of fermentation of sugar to ethanol in presence of Saccharomyces cerivisiae at very high gravity is described. The bifurcation analysis was done for a concentration 280 gl −1 of sugar, and the dilution rate was taken as the parameter of bifurcation. Two Hopf bifurcations (HB) at 280 gl −1 were found. At dilution rate of 0.027 h −1 the system exhibits damped oscillations and not sustained oscillations as previously reported because the system is close to a point of attraction, and we can attenuate these oscillations by the choice of initial conditions. The system exhibits sustained oscillations between the two Hopf Bifurcations, the first at 0.08028 h −1 and the second at 0.04395 h −1 . These oscillations are the consequence of synchrony between the daughter and the mother yeast. Indeed, it is better to take a dilution rate between the two Hopf bifurcations (self sustained oscillations), in order to increase the ethanol productivity.

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Real‐time dissolved carbon dioxide monitoring I: Application of a novel in situ sensor for CO₂ monitoring and control

Chopda

Holzberg

et al. 2020

Biotech & Bioengineering

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Dissolved carbon dioxide (dCO2) is a well‐known critical parameter in bioprocesses due to its significant impact on cell metabolism and on product quality attributes. Processes run at small‐scale faces many challenges due to limited options for modular sensors for online monitoring and control. Traditional sensors are bulky, costly, and invasive in nature and do not fit in small‐scale systems. In this study, we present the implementation of a novel, rate‐based technique for real‐time monitoring of dCO2 in bioprocesses. A silicone sampling probe that allows the diffusion of CO2 through its wall was inserted inside a shake flask/bioreactor and then flushed with air to remove the CO2 that had diffused into the probe from the culture broth (sensor was calibrated using air as zero‐point calibration). The gas inside the probe was then allowed to recirculate through gas‐impermeable tubing to a CO2 monitor. We have shown that by measuring the initial diffusion rate of CO2 into the sampling probe we were able to determine the partial pressure of the dCO2 in the culture. This technique can be readily automated, and measurements can be made in minutes. Demonstration experiments conducted with baker's yeast and Yarrowia lipolytica yeast cells in both shake flasks and mini bioreactors showed that it can monitor dCO2 in real‐time. Using the proposed sensor, we successfully implemented a dCO2‐based control scheme, which resulted in significant improvement in process performance.

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Dissolved carbon dioxide concentration profiles during very-high-gravity ethanol fermentation

Cited by 7 publications

References 25 publications

Ethanol Fermentation Under Dissolved Carbon Dioxide Control

Ethanol Fermentation Under Dissolved Carbon Dioxide Control

Continuous Ethanol Fermentation at Very High Gravity in the Presence of <i>Saccharomyces cerevisiae</i>: A Bifurcation Analysis

Real‐time dissolved carbon dioxide monitoring I: Application of a novel in situ sensor for CO₂ monitoring and control

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Dissolved carbon dioxide concentration profiles during very-high-gravity ethanol fermentation

Cited by 7 publications

References 25 publications

Ethanol Fermentation Under Dissolved Carbon Dioxide Control

Ethanol Fermentation Under Dissolved Carbon Dioxide Control

Continuous Ethanol Fermentation at Very High Gravity in the Presence of &lt;i&gt;Saccharomyces cerevisiae&lt;/i&gt;: A Bifurcation Analysis

Real‐time dissolved carbon dioxide monitoring I: Application of a novel in situ sensor for CO2 monitoring and control

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Continuous Ethanol Fermentation at Very High Gravity in the Presence of <i>Saccharomyces cerevisiae</i>: A Bifurcation Analysis

Real‐time dissolved carbon dioxide monitoring I: Application of a novel in situ sensor for CO₂ monitoring and control