Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/21/2006
Publication Date: 5/21/2006
Citation: Qureshi, N., Ezeji, T.C., Blaschek, H.P. 2006. Application of alternative product recovery techniques to acetone butanol (AB) fermentation: improving fermentation parameters. Proceedings of the Ninth International Workshop on the Regulation of Metabolism, Genetics, and Development of the Solvent and Acid Forming Clostridia. p. 23.
Technical Abstract: In a typical batch acetone butanol (AB) fermentation, sugar utilization of the order of 60 g/L is achieved due to severe product inhibition resulting in low AB concentration in broth and low productivity. Simultaneous recovery of AB is an approach that reduces inhibition and improves fermentation parameters in addition to separating the final product. The techniques that have been investigated for product recovery include adsorption, reverse osmosis, pervaporation, liquid-liquid extraction, perstraction, and gas stripping. Of these techniques, adsorption, pervaporation, liquid-liquid extraction, and gas stripping have been reported to be superior to other techniques. Three different pervaporation membranes (zeolite, zeolite-ceramic, and silicone) have been reported to recover butanol from fermentation broth. Although there are a number of advantages for using these membranes, their cost (>$3000/m**2, 750-1000/m**2, and $75-300/m**2, respectively) restricts their application at large scale. Gas stripping is a unique technique which does not require any chemical or membrane. Using gas stripping, AB was recovered from batch, fed-batch, and continuous fermentations. In these fermentations, 55, 500, and >1100 g/L (reactor volume) glucose was utilized, respectively. Some of these techniques were also applied to the fermentation of commercial substrates such as liquefied corn starch and degermed corn. As compared to batch fermentation, parameters such as productivity, yield, substrate utilization, and longevity of fermentation were improved. Improvements in these parameters and simultaneous product recovery make economics of AB production attractive as compared to the traditional batch fermentation and distillative recovery.