Industrial-Scale Syngas Fermentation and Commercialization
The major deficiency in the current syngas fermentation route is gas-to-liquid mass transfer limitation, which is the most difficult
barrier to overcome due to the poor solubility of the gaseous substrate, especially CO and H2, in fermentation medium. The low ethanol yield in the process is also a result of solubility limitation. The slow reaction rate and the need for sterile condition to prevent media contamination are also some disadvantages involved in biological processes. But in the case of syngas fermentation, the presence of CO in the gas stream ensures sterility as it is toxic to most microorganisms.
Even though there are considerable challenges, the potential of the fermentation route to produce ethanol from syngas has been established by various successful laboratory-scale research studies and pilot plant studies. So far three major companies have reported the successful operation of large facilities for high-volume ethanol production via syngas fermentation technology [11], and these industrial facilities include:
1. Coskata, Inc., Madison, Pennsylvania, USA; 2009; 50,000 gallons/year semi-commercial plant
2. INEOS Bio, Vero Beach, Florida, USA; 2008; 8 million gallon/year
3. LanzaTech, Glenbrook, New Zealand; 2010
There are a number of areas that can be focused on for improving the ethanol yield, which include genetic engineering of microorganisms to develop better biocatalysts, innovative reactor designs that can improve the mass transfer, and cost-effective fermentation mediums that can enhance the syngas solubility in the liquid phase. It is encouraging to see that all these aspects are currently under rigorous study in academic and industrial laboratories.
1. P. C. Munasinghe and S. K. Khanal, Chapter 4 — Biomass-derived syngas fermentation into biofuels, in Biofuels, P. Ashok, et al., Eds., 2011, Academic Press: Amsterdam. p. 79-98.
2. P. C. Munasinghe and S. K. Khanal, Biomass-derived syngas fermentation into biofuels: Opportunities and challenges. Bioresource Technology, 2010. 101(13): p. 5013-5022.
3. M. Mohammadi, G. D. Najafpour, H. Younesi, P. Lahijani, M. H. Uzir, and A. R. Mohamed, Bioconversion of synthesis gas to second generation biofuels: A review. Renewable and Sustainable Energy Reviews, 2011. 15(9): p. 4255-4273.
4. M. R. Wilkins and H. K. Atiyeh, Microbial production of ethanol from carbon monoxide. Current Opinion in Biotechnology, 2011. 22(3): p. 326-330.
5. D. K. Kundiyana, R. L. Huhnke, and M. R. Wilkins, Syngas fermentation in a 100-L pilot scale fermentor: Design and process considerations. Journal of Bioscience and Bioengineering, 2010. 109(5): p. 492-498.
6. A. M. Henstra, J. Sipma, A. Rinzema, and A. J. Stams, Microbiology of synthesis gas fermentation for biofuel production. Current Opinion in Biotechnology, 2007. 18(3): p. 200-206.
7. K. T. Klasson, C. M.D. Ackerson, E. C. Clausen, and J. L. Gaddy, Biological conversion of synthesis gas into fuels. International Journal of Hydrogen Energy, 1992. 17(4): p. 281-288.
8. H. L. Drake, S. L. Daniel, K. Kusel, C. Matthies, C. Kuhner, and S. Braus — Stromeyer, Acetogenic bacteria: What are the in situ consequences of their diverse metabolic versatilities. BioFactors, 1997. 6(1): p. 13-24.
9. S. W. Ragsdale, Metals and their scaffolds to promote difficult enzymatic reactions. Chemical Reviews, 2006. 106(8): p. 3317-3337.
10. M. Kopke, C. Held, S. Hujer, H. Liesegang, A. Wiezer, A. Wollherr, A. Ehrenreich, W. Liebl, G. Gottschalk, and P. Durre, Clostridium ljung — dahlii represents a microbial production platform based on syngas. Proceedings of the National Academy of Sciences of the United States of America, 2010. 107(29): p. 13087-13092.
11. M. Kopke, C. Mihalcea, J. C. Bromley, and S. D. Simpson, Fermentative production of ethanol from carbon monoxide. Current Opinion in Biotechnology, 2011. 22(3): p. 320-325.
12. L. G. Ljungdahl, The autotrophic pathway of acetate synthesis in acetogenic bacteria. Annual Review of Microbiology, 1986. 40: p. 415-450.
13. H. N. Abubackar, M. C. Veiga, and C. Kennes, Biological conversion of carbon monoxide: Rich syngas or waste gases to bioethanol. Biofuels, Bioproducts and Biorefining, 2011. 5(1): p. 93-114.
14. K. T. Klasson, M. D. Ackerson, E. C. Clausen, and J. L. Gaddy, Biological conversion of coal and coal-derived synthesis gas. Fuel, 1993. 72(12): p. 1673-1678.
15. J. R. Phillips, E. C. Clausen, and J. L. Gaddy, Synthesis gas as substrate for the biological production of fuels and chemicals. Applied Biochemistry and Biotechnology, 1994. 45-46(1): p. 145-157.
16. A. Ahmed, B. G. Cateni, R. L. Huhnke, and R. S. Lewis, Effects of biomass-generated producer gas constituents on cell growth, product distribution and hydrogenase activity of Clostridium carboxidivorans P7 T. Biomass and Bioenergy, 2006. 30(7): p. 665-672.
17. B. K. Babu, H. K. Atiyeh, M. R. Wilkins, and R. L. Huhnke, Effect of the reducing agent dithiothreitol on ethanol and acetic acid production by clostridium strain P11 using simulated biomass-based syngas. Biological Engineering, 2010. 3(2): p. 19-35.
18. J. Saxena and R. S. Tanner, Effect of trace metals on ethanol production from synthesis gas by the ethanologenic acetogen, Clostridium rags — dalei. Journal of Industrial Microbiology and Biotechnology, 2011. 38(4): p. 513-521.
19. A. Panneerselvam, M. R. Wilkins, M. J.M. DeLorme, H. K. Atiyeh, and R. L. Huhnke, Effects of various reducing agents on syngas fermentation by clostridium ragsdalei. Biological Engineering, 2010. 2(3): p. 135-144.
20. P. Maddipati, H. K. Atiyeh, D. D. Bellmer, and R. L. Huhnke, Ethanol production from syngas by Clostridium strain P11 using corn steep liquor as a nutrient replacement to yeast extract. Bioresource Technology, 2011. 102(11): p. 6494-6501.
21. D. K. Kundiyana, R. L. Huhnke, P. Maddipati, H. K. Atiyeh, and M. R. Wilkins, Feasibility of incorporating cotton seed extract in Clostridium strain P11 fermentation medium during synthesis gas fermentation. Bioresource Technology, 2010. 101(24): p. 9673-9680.
22. J. Abrini, H. Naveau, and E. J. Nyns, Clostridium autoethanogenum, sp. nov., an anaerobic bacterium that produces ethanol from carbon monoxide. Archives of Microbiology, 1994. 161(4): p. 345-351.
23. M. Misoph and H. L. Drake, Effect of CO2 on the fermentation capacities of the acetogen Peptostreptococcus productus U-1. Journal of Bacteriology, 1996. 178(11): p. 3140-3145.
24. H. G. Wood, S. W. Ragsdale, and E. Pezacka, The acetyl-CoA pathway of autotrophic growth. FEMS Microbiology Letters, 1986. 39(4): p. 345-362.
25. D. K. Kundiyana, M. R. Wilkins, P. Maddipati, and R. L. Huhnke, Effect of temperature, pH and buffer presence on ethanol production from synthesis gas by "Clostridium ragsdalei". Bioresource Technology, 2011. 102(10): p. 5794-5799.
26. H. Younesi, G. Najafpour, and A. R. Mohamed, Ethanol and acetate production from synthesis gas via fermentation processes using anaerobic bacterium, Clostridium ljungdahlii. Biochemical Engineering Journal, 2005. 27(2): p. 110-119.
27. J. R. Phillips, K. T. Klasson, E. C. Clausen, and J. L. Gaddy, Biological production of ethanol from coal synthesis gas — Medium development studies. Applied Biochemistry and Biotechnology, 1993. 39-40(1): p. 559-571.
28. J. L. Gaddy, Biological production of ethanol from waste gases with Clostridium ljungdahlii. US Patent No., 2000. 6,136,577.
29. J. L. Gaddy, Clausen, E. C., Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism. US Patent No., 1992. 5,173,429.
30. J. L. Cotter, M. S. Chinn, and A. M. Grunden, Influence of process parameters on growth of Clostridium ljungdahlii and Clostridium autoethanogenum on synthesis gas. Enzyme and Microbial Technology, 2009. 44(5): p. 281-288.
31. J. L. Vega, G. M. Antorrena, E. C. Clausen, and J. L. Gaddy, Study of gaseous substrate fermentations: Carbon monoxide conversion to acetate. 2. Continuous culture. Biotechnology and Bioengineering, 1989. 34(6): p. 785-793.
32. D. K. Kundiyana, R. L. Huhnke, and M. R. Wilkins, Effect of nutrient limitation and two-stage continuous fermentor design on productivities during "Clostridium ragsdalei" syngas fermentation. Bioresource Technology, 2011. 102(10): p. 6058-6064.
33. Y. Guo, J. Xu, Y. Zhang, H. Xu, Z. Yuan, and D. Li, Medium optimization for ethanol production with Clostridium autoethanogenum with carbon monoxide as sole carbon source. Bioresource Technology, 2010. 101(22): p. 8784-8789.
34. Y. Nie, H. Liu, G. Du, and J. Chen, Acetate yield increased by gas circulation and fed-batch fermentation in a novel syntrophic acetogenesis and homoacetogenesis coupling system. Bioresource Technology, 2008. 99(8): p. 2989-2995.
35. D. Xu and R. S. Lewis, Syngas fermentation to biofuels: Effects of ammonia impurity in raw syngas on hydrogenase activity. Biomass and Bioenergy, 2012. 45(0): p. 303-310.
36. D. Xu, D. R. Tree, and R. S. Lewis, The effects of syngas impurities on syngas fermentation to liquid fuels. Biomass and Bioenergy, 2011. 35(7): p. 2690-2696.
37. Y. Richardson, J. Blin, and A. Julbe, A short overview on purification and conditioning of syngas produced by biomass gasification: Catalytic strategies, process intensification and new concepts. Progress in Energy and Combustion Science, 2012. 38(6): p. 765-781.
38. S. D. Sharma, M. Dolan, D. Park, L. Morpeth, A. Ilyushechkin, K. McLennan, D. J. Harris, and K. V. Thambimuthu, A critical review of syngas cleaning technologies — fundamental limitations and practical problems. Powder Technology, 2008. 180(1-2): p. 115-121.
39. P. R. Afolabi, F. Mohammed, K. Amaratunga, O. Majekodunmi, S. L. Dales, R. Gill, D. Thompson, J. B. Cooper, S. P. Wood, P. M. Goodwin, and C. Anthony, Site-directed mutagenesis and X-ray crystallography of the PQQ-containing quinoprotein methanol dehydrogenase and its electron acceptor, cytochrome c L. Biochemistry, 2001. 40(33): p. 9799-9809.
40. M. Kashiwagi, K. I. Fuhshuku, and T. Sugai, Control of the nitrilehydrolyzing enzyme activity in Rhodococcus rhodochrous IFO 15564: Preferential action of nitrile hydratase and amidase depending on the reaction condition factors and its application to the one-pot preparation of amides from aldehydes. Journal of Molecular Catalysis B: Enzymatic, 2004. 29(1-6): p. 249-258.
41. A. Ahmed and R. S. Lewis, Fermentation of biomass-generated synthesis gas: Effects of nitric oxide. Biotechnology and Bioengineering, 2007. 97(5): p. 1080-1086.
42. H. Itoh, A. Hirota, K. Hirayama, T. Shin, and S. Murao, Properties of ascorbate oxidase produced by Acremonium sp. HI-25. Bioscience, Biotechnology and Biochemistry, 1995. 59(6): p. 1052-1056.
43. R. Picton, M. C. Eggo, G. A. Merrill, M. J.S. Langman, and S. Singh, Mucosal protection against sulphide: Importance of the enzyme rho- danese. Gut, 2002. 50(2): p. 201-205.
44. M. R. Hyman, S. A. Ensign, D. J. Arp, and P. W. Ludden, Carbonyl sulfide inhibition of CO dehydrogenase from Rhodospirillum rubrum. Biochemistry, 1989. 28(17): p. 6821-6826.
45. D. Xu and R. S. Lewis, Syngas fermentation to biofuels: Effects of ammonia impurity in raw syngas on hydrogenase activity. Biomass and Bioenergy, 2012. 45: p. 303-310.
46. K. M. Hurst and R. S. Lewis, Carbon monoxide partial pressure effects on the metabolic process of syngas fermentation. Biochemical Engineering Journal, 2010. 48(2): p. 159-165.
47. J. L. Vega, E. C. Clausen, and J. L. Gaddy, Design of bioreactors for coal synthesis gas fermentations. Resources, Conservation and Recycling, 1990. 3(2-3): p. 149-160.
48. K. T. Klasson, M. D. Ackerson, E. C. Clausen, and J. L. Gaddy, Bioconversion of synthesis gas into liquid or gaseous fuels. Enzyme and Microbial Technology, 1992. 14(8): p. 602-608.
49. K. T. Klasson, K. M.O. Lundback, E. C. Clausen, and J. L. Gaddy, Kinetics of light limited growth and biological hydrogen production from carbon monoxide and water by Rhodospirillum rubrum. Journal of Biotechnology, 1993. 29(1-2): p. 177-188.
50. E. J. Wolfrum and A. S. Watt, Bioreactor design studies for a hydrogen — producing bacterium. Applied Biochemistry and Biotechnology — Part A Enzyme Engineering and Biotechnology, 2002. 98-100: p. 611-625.