Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions
This study optimized ethanol production from sweet sorghum stem juice (SSJ) by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation in 500-mL air–locked flasks at 30 °C. Response surface methodology based on a Box-Behnken design was employed to optimize initial sugar (267 g/L), u...
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KeAi Communications Co., Ltd.
2025-03-01
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| Series: | Carbon Resources Conversion |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2588913324000632 |
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| author | Phon Thatiyamanee Pattana Laopaiboon Lakkana Laopaiboon |
| author_facet | Phon Thatiyamanee Pattana Laopaiboon Lakkana Laopaiboon |
| author_sort | Phon Thatiyamanee |
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| description | This study optimized ethanol production from sweet sorghum stem juice (SSJ) by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation in 500-mL air–locked flasks at 30 °C. Response surface methodology based on a Box-Behnken design was employed to optimize initial sugar (267 g/L), urea (3.24 g/L), and cell concentration (1.32 × 108 cells/mL) for maximization of ethanol concentration (PE), productivity (QP), and sugar consumption (%SC). The experimental values (PE, 119.29 g/L; QP, 2.49 g/L.h and %SC, 91.83 %) under optimal conditions were close to the predicted values, verifying the optimization process. Aeration (2.5 vvm for 4 h) increased viable cell counts and decreased glycerol production (a by-product), but not fermentation efficiency. An osmoprotectant (40 mM potassium chloride combined with 10 mM potassium hydroxide, KCl/KOH) at 30 °C had no positive effect on ethanol fermentation efficiency. However, at 25 °C, the osmoprotectant increased PE from 106 to 116 g/L and ethanol yield from 0.46 to 0.49 g/g. At 35–37 °C, it prolonged cell viability, increasing PE by 5–12 g/L and %SC by 3–8 % without affecting ethanol yield. However, at 39 °C, no positive impact occurred on ethanol fermentation efficiency. The findings from this study, particularly the optimized fermentation conditions and stress tolerance strategies, could guide the scale-up to an industrial level of bioethanol production from sweet sorghum stem juice or other feedstocks using VHG fermentation, contributing to the development of more efficient and sustainable biofuel production processes. |
| format | Article |
| id | doaj-art-f988c504cf9b48cfba1ad9e819b6cee9 |
| institution | Kabale University |
| issn | 2588-9133 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Carbon Resources Conversion |
| spelling | doaj-art-f988c504cf9b48cfba1ad9e819b6cee92025-02-05T04:32:30ZengKeAi Communications Co., Ltd.Carbon Resources Conversion2588-91332025-03-0181100274Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditionsPhon Thatiyamanee0Pattana Laopaiboon1Lakkana Laopaiboon2Graduate School, Khon Kaen University, Khon Kaen 40002, ThailandDepartment of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand; Fermentation Research Center for Value Added Agricultural Products (FerVAAP), Khon Kaen University, Khon Kaen 40002, ThailandDepartment of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand; Fermentation Research Center for Value Added Agricultural Products (FerVAAP), Khon Kaen University, Khon Kaen 40002, Thailand; Corresponding author at: Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand.This study optimized ethanol production from sweet sorghum stem juice (SSJ) by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation in 500-mL air–locked flasks at 30 °C. Response surface methodology based on a Box-Behnken design was employed to optimize initial sugar (267 g/L), urea (3.24 g/L), and cell concentration (1.32 × 108 cells/mL) for maximization of ethanol concentration (PE), productivity (QP), and sugar consumption (%SC). The experimental values (PE, 119.29 g/L; QP, 2.49 g/L.h and %SC, 91.83 %) under optimal conditions were close to the predicted values, verifying the optimization process. Aeration (2.5 vvm for 4 h) increased viable cell counts and decreased glycerol production (a by-product), but not fermentation efficiency. An osmoprotectant (40 mM potassium chloride combined with 10 mM potassium hydroxide, KCl/KOH) at 30 °C had no positive effect on ethanol fermentation efficiency. However, at 25 °C, the osmoprotectant increased PE from 106 to 116 g/L and ethanol yield from 0.46 to 0.49 g/g. At 35–37 °C, it prolonged cell viability, increasing PE by 5–12 g/L and %SC by 3–8 % without affecting ethanol yield. However, at 39 °C, no positive impact occurred on ethanol fermentation efficiency. The findings from this study, particularly the optimized fermentation conditions and stress tolerance strategies, could guide the scale-up to an industrial level of bioethanol production from sweet sorghum stem juice or other feedstocks using VHG fermentation, contributing to the development of more efficient and sustainable biofuel production processes.http://www.sciencedirect.com/science/article/pii/S2588913324000632BioethanolSweet sorghumVery high gravity fermentationTemperature stressOsmoprotectant |
| spellingShingle | Phon Thatiyamanee Pattana Laopaiboon Lakkana Laopaiboon Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions Carbon Resources Conversion Bioethanol Sweet sorghum Very high gravity fermentation Temperature stress Osmoprotectant |
| title | Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions |
| title_full | Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions |
| title_fullStr | Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions |
| title_full_unstemmed | Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions |
| title_short | Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions |
| title_sort | optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions |
| topic | Bioethanol Sweet sorghum Very high gravity fermentation Temperature stress Osmoprotectant |
| url | http://www.sciencedirect.com/science/article/pii/S2588913324000632 |
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