Bioethanol Production Through Syngas Fermentation by a Novel Immobilized Bioreactor Using Clostridium Ragsdalei


  • Simge Sertkaya Ege University
  • Tugba Keskin Gundogdu İzmir Demokrasi University
  • Christian Kennes University of A Coruña
  • Nuri Azbar Ege University



Air Pollution, Energy, Carbonmonoxide, Clostridium, Ethanol


Global energy demand has been escalating creating ever increasing pressure on climate crisis caused by fossil-based fuels. Humankind is now desperately in need of alternative and sustainable energy sources. Therefore, biofuels provide promising solution.

Amongst the various biofuels, bioethanol from syngas, which is a mixture of, mostly, CO, CO2, N2, H2, and CH4 gases has been drawing increasing attention recently. Regarding this, the conversion of syngas to bioethanol, an alternative biofuel to fossil fuels, is considered a promising approach to reduce the negative effects of global warming by reducing greenhouse gas emissions.

In this study, a novel immobilized cell bioreactor, where Clostridium ragsdalei was grown, was designed and used to achieve an efficient production of ethanol regarding volumetric production. For this purpose, a 300 mL immobilized reactor filled with ceramic balls as immobilization material was set and operated at 30oC throughout the study where CO gas as the main substrate was fed at rate of 6 ml/min continuously. Results showed ethanol and acetic acid concentrations reaching up to 1.4 g/L and 0.2 g/L, respectively, after 600h with a volumetric production rate of 0,0023g ethanol/L/h. We believe, the ceramic ball was used for bioethanol production for syngas for the first time.

Author Biographies

Tugba Keskin Gundogdu, İzmir Demokrasi University

Associate Professor, Department of Environmental Protection

Christian Kennes, University of A Coruña

Professor, Faculty of Sciences and Centre for Advanced Scientific Research

Nuri Azbar, Ege University

Professor, Department of Bioengineering


Abubackar, H.N., Veiga, M.C., Kennes, C. 2012. Biological conversion of carbon monoxide to ethanol: Effect of pH, gas pressure, reducing agent and yeast extract. Bioresource Technology, 114: 518–522.

Acharya, B., Dutta, A., Basu, P. 2019. Ethanol production by syngas fermentation in a continuous stirred tank bioreactor using Clostridium ljungdahlii, Biofuels, 10: 221–237., 2011. Subject: Syngas Fermentation - The Third Pathway for Cellulosic Ethanol. Report 1–6.

Arslan, K., Bayar, B., Abubackar, H.N., Veiga, M.C., Kennes, C. Solventogenesis in Clostridium aceticum producing high concentrations of ethanol from syngas, Bioresource Technology, 292: 121941.

Cotter, J.L., Chinn, M.S., Grunden, A.M. 2009. Influence of Process Parameters on Growth of Clostridium Ljungdahlii and Clostridium Autoethanogenum on Synthesis Gas, Enzyme and Microbial Technology, 44 (5):281–88. DOI : 10.1016/j.enzmictec.2008.11.002

Devarapalli, M., Atiyeh, H.K., Phillips, J.R., Lewis, R.S., Huhnke, R.L. 2016. Ethanol production during semi-continuous syngas fermentation in a trickle bed reactor using Clostridium ragsdalei. Bioresource Technology, 209: 56–65.

Devarapalli, M., Lewis, R.S., Atiyeh, H.K. 2017. Continuous Ethanol Production from Synthesis Gas by Clostridium ragsdalei in a Trickle-Bed Reactor, Fermentation, 3: 23. DOI:10.3390/fermentation3020023

Dürre, P. and Eikmanns, B.J., 2015. C1-carbon sources for chemical and fuel production by microbial gas fermentation, Current Opinion in Biotechnology, 35: 63-72.

Fernández-Naveira, Á., Abubackar, H.N., Veiga, M.C., Kennes, C., 2016. Carbon monoxide bioconversion to butanol-ethanol by Clostridium carboxidivorans: kinetics and toxicity of alcohols, Applied Microbiology and Biotechnology, 100: 4231-4240.

Fernández-Naveira, A., Veiga, M.C., Kennes, C. 2017. Glucose bioconversion profile in the syngas-metabolizing species Clostridium carboxidivorans, Bioresource Technology, 244(1): 552-559.

Köpke, M., Mihalcea,C., Bromley,J.C., Simpson, S.D. 2011. Fermentative Production of Ethanol from Carbon Monoxide, Current Opinion in Biotechnology, 22(3): 320-325.

Kundiyana D.K, Huhnke R.L, Wilkins M.R. 2010. Syngas fermentation in a 100-L pilot scale fermentor: Design and process considerations, Journal of Bioscience and Bioengineering, 109 (5): 492-498. DOI:10.1016/j.jbiosc.2009.10.022

Kundiyana D.K, Huhnke R.L, Wilkins M.R. 2011. Effect of nutrient limitation and two-stage continuous fermentor design on productivities during Clostridium ragsdalei syngas fermentation, Bioresource Technology, 102: 6058-6064.

Orgill, J.J., Atiyeh, H.K, Devarapalli, M., Phillips, J.R., Lewis, R.S., Huhnke, R.L., 2013. A comparison of mass transfer coefficients between trickle-bed, hollow fiber membrane and stirred tank reactors, Bioresource Technology, 133: 340-346.

Phillips, J.R., Huhnke, R.L., Atiyeh, H.K., 2017. Syngas Fermentation: A Microbial Conversion Process of Gaseous Substrates to Various Products, Fermentation, 3: 28.

Ramió-Pujol, S., Ganigué, R., Bañeras, L., Colprim, J., 2015. Impact of formate on the growth and productivity of Clostridium ljungdahlii PETC and Clostridium carboxidivorans P7 grown on syngas, International Microbiology, 17: 195-204.

Zhu, Y. 2007. Chapter 14 - Immobilized Cell Fermentation for Production of Chemicals and Fuels, Bioprocessing for Value-Added Products from Renewable Resources New Technologies and Applications, 373-396.



How to Cite

Sertkaya, S., Keskin Gundogdu, T., Kennes, C., & Azbar, N. (2021). Bioethanol Production Through Syngas Fermentation by a Novel Immobilized Bioreactor Using Clostridium Ragsdalei. ICONTECH INTERNATIONAL JOURNAL, 5(3), 13-20.