Production of acetone butanol ethanol (ABE) by a hyper-producing mutant strain of Clostridium beijierinckii BA101 and recovery by pervaporation

A silicone membrane was used to study butanol separation from model butanol solutions and fermentation broth. Depending upon the butanol feed concentr ation in the model solution and pervaporation conditions, butanol selectivi ties of 20.88-68.32 and flux values of 158.7-215.4 g m(-2) h(-1) were achie ved. Higher flux values (400 g m(-2) h(-1)) were obtained at higher butanol concentrations using air as sweep gas. In an integrated process of butanol fermentation-recovery, solvent productivities were improved to 200% of the control batch fermentation productivities. In a batch reactor the hyper-bu tanol-producing mutant strain C. beijerinckii BA101 utilized 57.3 g/L gluco se and produced 24.2 g/L total solvents, while in the integrated process it produced 51.5 g/L (culture volume) total solvents. Concentrated, glucose m edium was also fermented. The C. beijerinckii BA101 mutant strain was not n egatively affected by the pervaporative conditions. In the integrated exper iment, acids were not produced. With the active fermentation broth, butanol selectivity was reduced by a factor of 2-3. However, the membrane nux was not affected by the active fermentation broth. The butanol permeate concent ration ranged from 26.4 to 95.4 gn, depending upon butanol concentration in the fermentation broth. Since the permeate of most membranes contains acet one, butanol, and ethanol (and small concentrations of acids), it is sugges ted that distillation be used for further purification.