|KARCHER, PATRICK - UNIV OF IL
|EZEJI, THADDEUS - UNIV OF IL
|BLASCHEK, HANS - UNIV OF IL
Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2004
Publication Date: 5/12/2004
Citation: Karcher, P.M., Ezeji, T.C., Qureshi, N., Blaschek, H.P. 2004. Acetone butanol ethanol (ABE) fermentation by Clostridium beijerinckii BA101: effect of bubble size on the performance of a gas stripping-based recovery system [abstract]. Biotechnology for Fuels and Chemicals. Paper No. 3-08.
Technical Abstract: The effect of bubble size on the ability of gas stripping to remove acetone butanol ethanol (ABE) from a batch bioreactor was tested using two different bubble delivery systems. An impeller and a gas sparger were used to produce a bubble population of 0.5-5 mm and 0.5 mm diameters, respectively. Either gas stripping of butanol present in a solution containing 8 g/L was performed at a 43 or 80 mL/s gas recycle rate. The results demonstrated that bubble size had no effect on the butanol-stripping rate under the conditions tested. However, the stripping rate was seen to be proportional to the gas recycle rate. An experiment was carried out using a model solution containing ABE in proportions that are typical when employing Clostridium beijerinckii BA101. The presence of acetone and ethanol had no effect on the stripping rate of butanol. When the two gas delivery systems were used in the C. beijerinckii BA101 batch fermentation and recovery system, the bubbles produced by the gas sparger led to large amounts of foam in the reactor, which required addition of excessive amounts of antifoam. The solvent productivity of the bioreactor using impeller or sparger-based gas delivery systems was 0.47 and 0.25 g/L.h, respectively. The low productivity observed when a sparger gas delivery system was used is attributed to toxic effect of high levels of antifoam.