(264d) Attainable Region Analysis for Production of Butyl Butyrate Via Biochemical Route

EcoLodge aims at providing a proof-of-concept for a new, integrated biotechnological production process for C8 ester butyl butyrate, a promising supplement/substitute for diesel and jet engine fuels, from lignocellulose derived C5 and C6 sugars. Previous studies suggest that butyl butyrate has excellent properties both as gasoline and as a diesel component [1]. Butanol and butyric acid are the process intermediates produced via anaerobic fermentation, which undergo enzymatic esterification yielding the product, butyl butyrate.

The attainable region concept employs a computational/geometrical procedure for determining the boundaries of the region that include all possible reactor products for a known feed condition [2]. In this paper, we applied the attainable region concept to study different process configurations for biochemical production of butyl butyrate. These are i) butyl butyrate reactor with the feed from the butanol and butyric acid reactors, ii) combined butanol and butyl butyrate production with the feed from butyric acid reactor, and iii) combined butyric acid and butyl butyrate production with the feed from butanol reactor. We used mathematical models and model coefficients from the literature for cell growth, butyric acid and butanol fermentations, and their esterification for butyl butyrate production. Models include cell growth inhibition due to butanol and butyric acid, and enzyme inhibition due to butanol, butyric acid and glucose [3-5].

In this paper, we demonstrated the capabilities of the attainable region analysis as a tool to assess different process configurations for butyl butyrate production. Process configuration ii) showed the highest capability for butyl butyrate production, since the butyric acid enhances the butanol production, and butanol esterification decreases butanol inhibition on the cell growth. The results of this study will be employed in the experimental phase of the project.

1. Lange, J. P., Price, R., Ayoub, P. M., Louis, J., Petrus, L., Clarke, L., & Gosselink, H. (2010). Valeric biofuels: a platform of cellulosic transportation fuels. Angewandte Chemie International Edition, 49(26), 4479-4483.
2. Milne, D., Glasser, D., Hildebrandt, D., & Hausberger, B. (2004). Application of the attainable region concept to the oxidative dehydrogenation of 1-Butene in inert porous membrane reactors. Industrial & engineering chemistry research, 43(8), 1827-1831.
3. Yang, X., & Tsao, G. T. (1994). Mathematical modeling of inhibition kinetics in acetone-butanol fermentation by Clostridium acetobutylicum. Biotechnology progress, 10(5), 532-538.
4. Varma, M. N., & Madras, G. (2008). Kinetics of synthesis of butyl butyrate by esterification and transesterification in supercritical carbon dioxide. Journal of chemical technology and biotechnology, 83(8), 1135-1144.
5. Song, H., Eom, M. H., Lee, S., Lee, J., Cho, J. H., & Seung, D. (2010). Modeling of batch experimental kinetics and application to fed-batch fermentation of Clostridium tyrobutyricum for enhanced butyric acid production. Biochemical Engineering Journal, 53(1), 71-76.