Butanol, a diesel-fuel extender, can be produced by fermentation of a variety of sugar sources by Clostridium acetobutylicum. Although industrial production of butanol has not been significant in the U.S. in the past 30 years, two recent major developments present sufficient encouraging results to suggest that butanol yields can be improved. These are the capability to monitor intracellular NAD(P)H and the increased butanol production by the organism when cultured under extreme reducing conditions. This project, therefore, aims to conduct butanol fermentations under defined cellular states by the addition of reducing agents so as to maximize the yield of butanol.The potential commercial application as described by the awardee: The proposed research will ultimately result in a more economical butanol fermentation process. The technology of monitoring and altering the cell reduction state will be applicable to several other fermentation processes.