Pilot-scale production of butanol by Clostridium beijerinckii BA101 using a low-cost fermentation medium based on corn steep water

To improve the economic competitiveness of the acetone/butanol/ethanol ferm entation process, glucose/corn steep water (CSW) medium was used on a pilot scale for the production of solvents. The production of butanol by the Clo stridium beijerinckii NCIMB 8052 parent strain and the solvent-hyperproduci ng BA101 mutant was compared. In a 20-1 fermentation using 5% glucose/CSW m edium, C. beijerinckii 8052 produced 8.5 g butanol/l and 5 g acetone/l, whi le C. beijerinckii BA101 produced 16 g butanol/l and 7.5 g acetone/l. Furth er studies were carried out on a larger scale using an optimized 6% glucose /CSW medium. In a 200-1 pilot-scale fermenter, C. beijerinckii 8052 produce d 12.7 g butanol/l and 6 g acetone/l following 96 h of fermentation. C. bei jerinckii BA101 produced 17.8 g/l and 5.5 g/l butanol and acetone respectiv ely, following 130 h of fermentation. These results represent a 40% increas e in final butanol concentration by the C. beijerinckii BA101 mutant strain when compared to the 8052 parent strain. The total solvents (acetone, buta nol, and ethanol) produced by C. beijerinckii NCIMB 8052 and BA101 in a 200 -1 fermentation were 19.2 g/l and 23.6 g/l respectively. This is the first report of pilot-scale butanol production by the solvent-hyperproducing C. b eijerinckii BA101 mutant employing an inexpensive glucose/CSW medium.