Alcoholic fermentation with high sugar and cell concentration at moderate temperatures using flocculant yeasts

Brandão, Ana Carolina Tolentino; Resende, Miriam Maria de; Ribeiro, Eloízio Júlio

doi:10.1007/s11814-020-0589-z

Cited by 3 publications

(1 citation statement)

References 15 publications

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“…Commonly known for their high auto-immobilization capacity, self-flocculating strains seems to be superior to those immobilized on a physical support; they are naturally retained inside the reactor (when flocs of an appropriate size are formed) with no visible problems on cell growth, being recovered by a simple sedimentation, rather than using centrifuges [1,38,96]. Different reactor configurations have been tested with these strains including air-lift reactors [97][98][99][100], single-tower reactors [101,102], and two-tower reactors connected in series [103].…”

Section: Cells Immobilizationmentioning

confidence: 99%

Very High Gravity Bioethanol Revisited: Main Challenges and Advances

et al. 2021

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Over the last decades, the constant growth of the world-wide industry has been leading to more and more concerns with its direct impact on greenhouse gas (GHG) emissions. Resulting from that, rising efforts have been dedicated to a global transition from an oil-based industry to cleaner biotechnological processes. A specific example refers to the production of bioethanol to substitute the traditional transportation fuels. Bioethanol has been produced for decades now, mainly from energy crops, but more recently, also from lignocellulosic materials. Aiming to improve process economics, the fermentation of very high gravity (VHG) mediums has for long received considerable attention. Nowadays, with the growth of multi-waste valorization frameworks, VHG fermentation could be crucial for bioeconomy development. However, numerous obstacles remain. This work initially presents the main aspects of a VHG process, giving then special emphasis to some of the most important factors that traditionally affect the fermentation organism, such as nutrients depletion, osmotic stress, and ethanol toxicity. Afterwards, some factors that could possibly enable critical improvements in the future on VHG technologies are discussed. Special attention was given to the potential of the development of new fermentation organisms, nutritionally complete culture media, but also on alternative process conditions and configurations.

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Section: Cells Immobilizationmentioning

confidence: 99%

Very High Gravity Bioethanol Revisited: Main Challenges and Advances

et al. 2021

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Formation of isoamyl alcohol and isobutanol in the fermentation of sugarcane molasses in a microdistillery: evaluation of pH, refrigeration and supplementation factors

Santos,

de Almeida,

Andrade

et al. 2024

Preprint

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Fusel oil is a mixture of higher alcohols that are formed during fermentation, and the main constituents are isoamyl alcohol and isobutanol. Although their presence in fermented musts is detrimental to the distillation process and ethanol quality, the aforementioned higher alcohols are widely used, especially in the fine chemical industry. On the other hand, the quality and quantity of fusel oil depend on various factors, including raw materials and fermentation conditions. The aim of this study was to investigate the effects of pH, refrigeration, and supplementation on the formation of isoamyl alcohol and isobutanol during the fermentation of molasses must in a microdistillery. The fermentations were conducted in batches that were fed with 25 °Brix must and 25% v/v commercial dry yeast for 10 hours. A complete 2³ factorial design was used to assess the effects of the studied factors and their interactions on the response variables: fermentation efficiency (nf), process efficiency (np), ethanol productivity (P), substrate-to-cell conversion factor (YX/S), isoamyl alcohol produced (A), isobutanol produced (B) and the A/B Ratio between these alcohols. For statistical analysis, analysis of variance (ANOVA) and Tukey’s test were used for mean comparisons. The results of the substrate-to-cell conversion factor (YX/S) indicated good yeast performance under different fermentation conditions. The interaction effects among the evaluated factors significantly influenced the formation of isoamyl alcohol and isobutanol, as well as the A/B Ratio.

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Isoamyl alcohol and isobutanol production in sugarcane molasses fermentation in a microdistillery: pH, refrigeration, and supplementation effects

Santos,

Almeida,

Andrade

et al. 2024

Preprint

View full text Add to dashboard Cite

Fusel oil, a blend of higher alcohols generated during fermentation, predominantly comprises isoamyl alcohol and isobutanol. Despite their adverse effects on distillation and ethanol quality, these alcohols find widespread use, notably in the fine chemical industry. Fusel oil quality and quantity vary due to multiple factors, including raw materials and fermentation conditions. This study aimed to investigate the effects of pH, refrigeration, and supplementation on isoamyl alcohol and isobutanol formation during molasses must fermentation in a microdistillery. The fermentations were conducted in batches that were fed with 25 °Brix must and 25% v/v commercial dry yeast for 10 hours. A complete 2³ factorial design was used to assess the effects of the studied factors and their interactions on the response variables: fermentation efficiency (nf), process efficiency (np), ethanol productivity (P), substrate-to-cell conversion factor (YX/S), isoamyl alcohol produced (A), isobutanol produced (B) and the A/B Ratio between these alcohols. Statistical analysis employed ANOVA and Tukey’s test. The results of the substrate-to-cell conversion factor (YX/S) indicated good yeast performance under different fermentation conditions. The interaction effects among the evaluated factors significantly influenced the formation of isoamyl alcohol and isobutanol, as well as the A/B Ratio.

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Alcoholic fermentation with high sugar and cell concentration at moderate temperatures using flocculant yeasts

Cited by 3 publications

References 15 publications

Very High Gravity Bioethanol Revisited: Main Challenges and Advances

Very High Gravity Bioethanol Revisited: Main Challenges and Advances

Formation of isoamyl alcohol and isobutanol in the fermentation of sugarcane molasses in a microdistillery: evaluation of pH, refrigeration and supplementation factors

Isoamyl alcohol and isobutanol production in sugarcane molasses fermentation in a microdistillery: pH, refrigeration, and supplementation effects

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