Development of a cost-effective glucose corn steep medium for production of butanol by Clostridium beijerinckii

Corn steep water (CSW) medium (1.6% solids plus 6% glucose) was evaluated f or growth and butanol production by Clostridium beijerinckii NCIMB 8052 wil d-type and hyper-amylolytic, hyper-butanol-producing mutant strain BA101. C SW alone was not a suitable substrate, whereas addition of glucose supporte d growth and butanol production by both strains. In a batch-scale fermentat ion using an optimized 6% glucose-1.6% solids CSW medium, C. beijerinckii N CIMB 8052 and strain BA101 produced 10.7 g L-1 and 14.5 g L-1 of butanol, r espectively. The total solvents (acetone, butanol, and ethanol) produced by C. beijerinckii NCIMB 8052 and strain BA101 were 14 g L-1 and 20 g L-1, re spectively. Initial fermentation in small-scale flasks containing 6% maltod extrin-1.6% solids concentration CSW medium resulted in 6 g L-1 and 12.6 g L-1 of butanol production by C. beijerinckii NCIMB 8052 and strain BA101, r espectively. CSW can serve as an economic source of nitrogen, vitamins, ami no acids, minerals, and other nutrients. Thus, it is feasible to use 6% glu cose-1.6% solids CSW medium in place of semi-defined P2 medium.