Studies on bio-ethanol production using fermentation by free and immobilized yeast cells

  • P Manasa
  • Narasimhulu Korrapati Department of Biotechnology, National Institute of Technology Warangal, Telangana-506004, India.
  • Paramjeet Saroj
Keywords: Immobilized cells, fermentation, recyclability, alginate, bioethanol, glucose.


Background: Production of bioethanol from yeast cells is very important to meet the energy crisis and this work mainly concentrated on bioethanol production by free and immobilized yeast cells.Methods: Batch fermentation with free and immobilized yeast cells was done and compared.Result: The maximum concentration of ethanol was reached around 48 h which was 30.02 gL-1 and 28.78 gL-1 for S.cerevisiae and Baker’s yeast respectively. The maximum ethanol concentrations for each sets were 30.5 gL-1, 27.6 gL-1, and 28.2 gL-1 for subsequent sets of immobilized S.cerevisiae and 28.2 gL-1, 27.6 gL-1, and 26.98 gL-1for subsequent sets of immobilized baker’s yeastConclusion: As the total time for immobilized cells experiments was 3 sets of 56 h each or 168 h, it shows the stability of cells and longer functional period. However, as the ethanol concentration was stagnant after 8h, one must reduce the time period of set readings to 4h or 6h. However, the maximum ethanol concentration was observed after 48h from the inoculation of the culture in all the cases which shows a promising time period to be targeted industrially. In conclusion, the immobilized cells have significant advantage over free cells using sodium alginate as the immobilizing agent. More research focused on the size, cell density and industrial scale studies using packed bed or tubular reactor must be done to analyze it better.  DOI: 10.21276/AABS.1508

Author Biography

Narasimhulu Korrapati, Department of Biotechnology, National Institute of Technology Warangal, Telangana-506004, India.
Biotechnology, Assistant Professor


1. A, R., S, L., & M, P. (2011). Ethanol production by repeated batch and continuous fermentations of blackstrap molasses using immobilized yeast cells on thin-shell silk cocoons. Appl Energ, 88:4400–4404.
2. C, L., F, W., & F, O.-Y. (2009). Ethanol fermentation in a magnetically fluidized bed reactor with immobilized Saccharomyces cerevisiae in magnetic particles. Bioresource Technol, 100:878–882.
3. DS, I., DP, T., SN, C., AS, M., & CR, R. (1983). Ethanol production by S. cerevisiae immobilized in hollow-fiber membrane bioreactors. Appl Environ Microb, 46:264–278.
4. FW, B., WA, A., & M, M.-Y. (2008). Ethanol fermentation technologies from sugar and starch feedstocks. Biotechnol Adv, 26:89–105.
5. L, O., & B, H.-H. (1993). Fermentative performance of bacteria and yeast in lignocellulose hydrolysates. Process Biochem, 28:249–257.
6. L, O., & J, N. (2000). The role of metabolic engineering in the improvement of Saccharomyces cerevisiae: utilization of industrial media. Enzyme Microb Tech , 26:785–792.
7. Martinez, D., & Ebenhack, B. (2008). Energy Policy 36. 1430-1435.
8. P, P., RM, P., JK, R., & VSR, O. (2011). Repeated batch ethanolic fermentation of very high gravity medium by immobilized Saccharomyces cerevisiae. Ann Microbiol, 61:863–869.
9. P.C. Badger. (2002). Ethanol from Cellulose: A General Review. Trends in New Crops and New Uses, pp. 17-21.
10. PY, W., & H, S. (1980). Growth of yeasts on D-xylulose. Can J Microbiol, 26:1165–1168.
11. PY, W., C, S., & H, S. (1980). Fermentation of a pentose by yeasts. Biochem Biophys Res Commun, 94:248–254.
12. R, W., A, F., PJS, M., JAR, R., E, T., & K, A. (2001). Continuous fermentation of sugar cane syrup using immobilized yeast cells. J Biosci Bioeng, 91:48–52.
13. S, N., L, M., D, P., M, R., & M, V. (2010). Production of bioethanol from corn meal hydrolizates by free and immobilized cells of Saccharomyces cerevisiae var. ellipsoideus. Biomass Bioenerg, 34:1449–1456.
14. Seo, H.-B., Kim, H.-J., Lee, O.-K., Ha, J.-H., Lee, H.-Y., & Jung, K.-H. (2009 ). Measurement of ethanol concentration using solvent extraction and dichromate oxidation and its application to bioethanol production process. J Ind Microbiol Biotechnol , 36:285–292.
15. W, Y., X, W., J, Z., B, S., YY, Z., & C, M. (2011). Bacterial cellulose membrane – A new support carrier for yeast immobilization for ethanol fermentation. Process Biochem, 46:2054–2058.
16. Y, L., & S, T. (2006). Ethanol fermentation from biomass resources: Current state and prospects. Appl Microbiol Biot, 69:627–642.
17. Z, Z., G, L., & Y, L. (2010). Immobilization of Saccharomyces cerevisiae alcohol dehydrogenase on hybrid alginate-chitosan beads. Int J Biol Macromol, 47:21–26.
Original Article