Background and objective: Sweet sorghum is a sugar-rich crop with considerable potential as a feedstock for bioethanol production. This study aimed to characterize sweet sorghum juice and evaluate its alcoholic bioconversion by Zymomonas mobilis isolated from palm wine, using Saccharomyces cerevisiae as a reference microorganism. Material and methods: Z. mobilis was isolated from fresh palm wine on Wallerstein Laboratory (WL) medium, purified, and cultivated on a standard medium. Its ethanol tolerance was compared with that of S. cerevisiae at different ethanol concentrations. Sweet sorghum juice was extracted by pressing and characterized for dry matter, ash, total and reducing sugars, nitrogen, and selected mineral elements. Fermentation was performed under non-aerated conditions at 30°C in a 2-L fermenter using a Z. mobilis preculture corresponding to 10% of the final volume. Results: Colonies attributed to Z. mobilis on WL medium were lenticular and appeared after 4-5 days of incubation at 30°C. The isolate showed growth at ethanol concentrations ranging from 2.5% to 10%. Sweet sorghum juice had a mean dry matter content of 25.97 g/100 mL and mean total and reducing sugar contents of 18.99 and 19.12 g/100 mL, respectively. Fermentation with Z. mobilis did not result in a significant decrease in °Brix, which declined from 17°B initially to 16.5°B after 3 days and 16.3°B after 6 days. In contrast, the S. cerevisiae control produced an alcohol content of 5% with a reported yield of 50%. Conclusion: Under the experimental conditions investigated, the Z. mobilis strain isolated from palm wine did not efficiently ferment sweet sorghum juice. This failure may be associated with the nutritional characteristics of the substrate, preculture preparation conditions, or the physiological properties of the strain. Further studies involving more precise microbiological identification, optimization of the culture medium, and analytical monitoring of fermentation metabolites are warranted.
| Published in | International Journal of Microbiology and Biotechnology (Volume 11, Issue 4) |
| DOI | 10.11648/j.ijmb.20261104.12 |
| Page(s) | 163-168 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2026. Published by Science Publishing Group |
Sweet Sorghum, Bioethanol, Zymomonas Mobilis, Saccharomyces Cerevisiae, Alcoholic Fermentation
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APA Style
Ngom, B., Tounkara, L. S., Gueye, P., Wade, S. F., Ndiaye, M. (2026). Bioconversion of Sweet Sorghum Stalk Sugars into Ethanol by Zymomonas mobilis Isolated from Palm Wine. International Journal of Microbiology and Biotechnology, 11(4), 163-168. https://doi.org/10.11648/j.ijmb.20261104.12
ACS Style
Ngom, B.; Tounkara, L. S.; Gueye, P.; Wade, S. F.; Ndiaye, M. Bioconversion of Sweet Sorghum Stalk Sugars into Ethanol by Zymomonas mobilis Isolated from Palm Wine. Int. J. Microbiol. Biotechnol. 2026, 11(4), 163-168. doi: 10.11648/j.ijmb.20261104.12
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Download@article{10.11648/j.ijmb.20261104.12,
author = {Babacar Ngom and Lat Souk Tounkara and Papa Gueye and Serigne Fallou Wade and Mady Ndiaye},
title = {Bioconversion of Sweet Sorghum Stalk Sugars into Ethanol by Zymomonas mobilis Isolated from Palm Wine},
journal = {International Journal of Microbiology and Biotechnology},
volume = {11},
number = {4},
pages = {163-168},
doi = {10.11648/j.ijmb.20261104.12},
url = {https://doi.org/10.11648/j.ijmb.20261104.12},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmb.20261104.12},
abstract = {Background and objective: Sweet sorghum is a sugar-rich crop with considerable potential as a feedstock for bioethanol production. This study aimed to characterize sweet sorghum juice and evaluate its alcoholic bioconversion by Zymomonas mobilis isolated from palm wine, using Saccharomyces cerevisiae as a reference microorganism. Material and methods: Z. mobilis was isolated from fresh palm wine on Wallerstein Laboratory (WL) medium, purified, and cultivated on a standard medium. Its ethanol tolerance was compared with that of S. cerevisiae at different ethanol concentrations. Sweet sorghum juice was extracted by pressing and characterized for dry matter, ash, total and reducing sugars, nitrogen, and selected mineral elements. Fermentation was performed under non-aerated conditions at 30°C in a 2-L fermenter using a Z. mobilis preculture corresponding to 10% of the final volume. Results: Colonies attributed to Z. mobilis on WL medium were lenticular and appeared after 4-5 days of incubation at 30°C. The isolate showed growth at ethanol concentrations ranging from 2.5% to 10%. Sweet sorghum juice had a mean dry matter content of 25.97 g/100 mL and mean total and reducing sugar contents of 18.99 and 19.12 g/100 mL, respectively. Fermentation with Z. mobilis did not result in a significant decrease in °Brix, which declined from 17°B initially to 16.5°B after 3 days and 16.3°B after 6 days. In contrast, the S. cerevisiae control produced an alcohol content of 5% with a reported yield of 50%. Conclusion: Under the experimental conditions investigated, the Z. mobilis strain isolated from palm wine did not efficiently ferment sweet sorghum juice. This failure may be associated with the nutritional characteristics of the substrate, preculture preparation conditions, or the physiological properties of the strain. Further studies involving more precise microbiological identification, optimization of the culture medium, and analytical monitoring of fermentation metabolites are warranted.},
year = {2026}
}
TY - JOUR T1 - Bioconversion of Sweet Sorghum Stalk Sugars into Ethanol by Zymomonas mobilis Isolated from Palm Wine AU - Babacar Ngom AU - Lat Souk Tounkara AU - Papa Gueye AU - Serigne Fallou Wade AU - Mady Ndiaye Y1 - 2026/10/29 PY - 2026 N1 - https://doi.org/10.11648/j.ijmb.20261104.12 DO - 10.11648/j.ijmb.20261104.12 T2 - International Journal of Microbiology and Biotechnology JF - International Journal of Microbiology and Biotechnology JO - International Journal of Microbiology and Biotechnology SP - 163 EP - 168 PB - Science Publishing Group SN - 2578-9686 UR - https://doi.org/10.11648/j.ijmb.20261104.12 AB - Background and objective: Sweet sorghum is a sugar-rich crop with considerable potential as a feedstock for bioethanol production. This study aimed to characterize sweet sorghum juice and evaluate its alcoholic bioconversion by Zymomonas mobilis isolated from palm wine, using Saccharomyces cerevisiae as a reference microorganism. Material and methods: Z. mobilis was isolated from fresh palm wine on Wallerstein Laboratory (WL) medium, purified, and cultivated on a standard medium. Its ethanol tolerance was compared with that of S. cerevisiae at different ethanol concentrations. Sweet sorghum juice was extracted by pressing and characterized for dry matter, ash, total and reducing sugars, nitrogen, and selected mineral elements. Fermentation was performed under non-aerated conditions at 30°C in a 2-L fermenter using a Z. mobilis preculture corresponding to 10% of the final volume. Results: Colonies attributed to Z. mobilis on WL medium were lenticular and appeared after 4-5 days of incubation at 30°C. The isolate showed growth at ethanol concentrations ranging from 2.5% to 10%. Sweet sorghum juice had a mean dry matter content of 25.97 g/100 mL and mean total and reducing sugar contents of 18.99 and 19.12 g/100 mL, respectively. Fermentation with Z. mobilis did not result in a significant decrease in °Brix, which declined from 17°B initially to 16.5°B after 3 days and 16.3°B after 6 days. In contrast, the S. cerevisiae control produced an alcohol content of 5% with a reported yield of 50%. Conclusion: Under the experimental conditions investigated, the Z. mobilis strain isolated from palm wine did not efficiently ferment sweet sorghum juice. This failure may be associated with the nutritional characteristics of the substrate, preculture preparation conditions, or the physiological properties of the strain. Further studies involving more precise microbiological identification, optimization of the culture medium, and analytical monitoring of fermentation metabolites are warranted. VL - 11 IS - 4 ER -
Department of Agricultural, Food and Nutritional Sciences and Techniques (DSTAAN), Amadou Mahtar Mbow University (UAM), Dakar, Senegal
Department Biotechnology, Food Technology Institute (ITA), Dakar, Senegal
Department of Animal Biology (BA) / Faculty of Science and Technology (FST) / UCAD, Dakar, Senegal
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