Submitted to: Applied Biochemistry and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 2003
Publication Date: March 1, 2004
Citation: Qureshi, N., Karcher, P., Cotta, M.A., Blaschek, H.P. 2004. High-productivity continuous biofilm reactor for butanol production: effect of acetate, butyrate, and corn steep liquor on bioreactor performance. Journal of Applied Biochemistry and Biotechnology. 113:713-721. Interpretive Summary: Bioreactors play an important role in the production of chemicals from agricultural biomass such as corn and corn products. In this paper we developed a bioreactor system which retains high cell mass of Clostridium beijerinckii, thus resulting in faster production rates of chemicals such as butanol. Butanol is a liquid fuel and can be produced from corn using C. beijerinckii. In order to make the bioreactor system efficient and economic, we fed corn steep liquor (CSL) to support cell growth and make the reactor productive. The rate of production of butanol from CSL fed reactors was comparable to that of a synthetic medium. The use of CSL is a viable alternative to synthetic media which are expensive to use for applications such as butanol production.
Technical Abstract: Corn steep liquor (CSL), a byproduct of corn wet milling process, was used in an immobilized cell continuous biofilm reactor to replace the expensive P2 medium ingredients. Use of CSL resulted in the production of 6.29 g/L total ABE as compared to the ABE level of 6.86 g/L in a control experiment. These studies were performed at a dilution rate of 0.32 h**-1. The productivities in the control and CSL experiment were 2.19 and 2.01 g/L.h, respectively. Since these values are similar, CSL may be used to replace the P2 medium. It has also been demonstrated that inclusion of butyric acid into the feed was beneficial to the butanol fermentation. A control experiment produced 4.77 g/L total ABE while the experiment with supplemented butyric acid produced 5.70 g/L total ABE. The butanol concentration increased from 3.14 g/L to 4.04 g/L. Inclusion of acetate into the feed medium of the immobilized cell biofilm reactor was not found to be beneficial for the ABE fermentation as reported for the batch ABE fermentation.