Optimization of Syngas Feed for Improved Bioethanol Production with Clostridium Ragsdalei

Abstract

In recent years air pollution has been seriously affecting human health. One of the main contributors to this problem is the formation of syngas from industrial processes. This gas consists of hazardous components including CO, COX, NOX. The fermentation of these C1 gases to produce bioethanol is one of the novel solutions towards a cleaner environment. Considering, the foreseen exhaustion of fossil fuels in 50 years, the production of bioethanol appears as a valuable solution towards this emerging need for alternative energy sources. In this context, in the present study, Clostridium ragsdalei was used to evaluate the effects of incrementing volumes (5, 10, 15, 20, 25 mL) of syngas feed on growth and ethanol production by using two different media namely basal ATCC media and Differential Reinforced Clostridial Media (DRCM). The highest yield achieved with 20 mL of syngas was 600 mg/L with the commonly used ATCC media. On the other hand, while this media resulted in higher ethanol yields, the utilization of its counterpart media (DRCM) gave interesting results with the production of acetate reaching almost 3000 mg/L. These results demonstrated the effectiveness of ATCC media with the optimized volume of syngas feed to produce bioethanol.

Keywords

• Bioethanol
• Syngas
• C1 gases
• Clostridium ragsdalei
• Acetate

References

1. Abubackar, H.N., Veiga, M.C.& Kennes, C., (2015). Carbon monoxide fermentation to ethanol by Clostridium autoethanogenum in a bioreactor with no accumulation of acetic acid. Bioresour. Technol. 186, 122–127.
2. Adıgüzel, O. (2013). Lignoselülozik materyallerden biyoetanol üretimi için kullanılan ön-muamele ve hidroliz yöntemleri. SAU J. Sci 17, 381–397.
3. Dürre, P.& Eikmanns, B.J. (2015). C1-carbon sources for chemical and fuel production by microbial gas fermentation. Curr. Opin. Biotechnol. 35, 63–72.
4. Gao, J., Atiyeh, H.K., Phillips, J.R., Wilkins, M.R. & Huhnke, R.L. (2013). Development of low cost medium for ethanol production from syngas by Clostridium ragsdalei. Bioresour. Technol. 147, 508–515.
5. Gunay, B., Azbar, N.& Keskin, T. (2020). The effect of corn syrup and whey on the conversion process of CO to ethanol using Clostridium ljungdahlii. Chemosphere 261, 127734.
6. 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. Bioresour. Technol. 102, 6058–6064.
7. Liberato, V., Benevenuti, C., Coelho, F., Botelho, A., Amaral, P., Pereira, N., Ferreira, T. (2019). Chemicals Production in a Biorefinery Context. Catalysts 1, 1–37.
8. Liu, K., Atiyeh, H.K., Tanner, R.S., Wilkins, M.R. & Huhnke, R.L. (2012). Fermentative production of ethanol from syngas using novel moderately alkaliphilic strains of Alkalibaculum bacchi. Bioresour. Technol. 104, 336–341.

9. Maddipati, P., Atiyeh, H.K., Bellmer, D.D. & Huhnke, R.L.(2011). Ethanol production from syngas by Clostridium strain P11 using corn steep liquor as a nutrient replacement to yeast extract. Bioresour. Technol. 102, 6494–6501.
10. Martin, M.E., Richter, H., Saha, S. & Angenent, L.T. (2016). Traits of selected Clostridium strains for syngas fermentation to ethanol. Biotechnol. Bioeng. 113, 531–539.
11. Miranda, J.C. de C., Ponce, G.H.S.F., Arellano-Garcia, H., Maciel Filho, R. & Wolf Maciel, M.R.(2020). Process design and evaluation of syngas-to-ethanol conversion plants. J. Clean. Prod. 269, 122078.
12. Monir, M.U., Yousuf, A. & Aziz, A.A., (2020). Syngas fermentation to bioethanol, in: Lignocellulosic Biomass to Liquid Biofuels. Elsevier, 195–216.
13. Oelgeschläger, E. & Rother, M., (2008). Carbon monoxide-dependent energy metabolism in anaerobic bacteria and archaea. Arch. Microbiol. 190, 257–269.
14. Phillips, J.R., Huhnke, R.L. & Atiyeh, H.K. (2017). Syngas fermentation: A microbial conversion process of gaseous substrates to various products. Fermentation 3(2), 28.
15. Schiel-Bengelsdorf, B. & Dürre, P. (2012). Pathway engineering and synthetic biology using acetogens. FEBS Lett. 586, 2191–2198.
16. Wilkins, M.R. & Atiyeh, H.K. (2011). Microbial production of ethanol from carbon monoxide. Curr. Opin. Biotechnol. 22(3), 326-330.
17. Younesi, H., Najafpour, G., Mohamed, A. R. (2005) Ethanol and acetate production from synthesis gas via fermentation processes using anaerobic bacterium, Clostridium ljungdahlii, Biochem. Eng. J., 27, 110-119.