Butanol Production by Submerged Fermentation of White Grape Pomace

White grape pomace, containing residual fermentable sugar, has been evaluated as a substrate for production of butanol by submerged fermentation using Clostridium saccharobutylicum P262. Using an initial value of pH 5.5, an inoculum size of 10% (v/v) and addition of supplementary yeast extract (10 g/l), butanol concentrations of up to 6 g/l were obtained, at a yield, based on sugar utilized, of 0.2 g/g. Significantly, the requirement for supplementary yeast extract could be replaced by selected salts, indicating that white grape pomace is not lacking in any organic nutrients for growth of, and butanol production by, C. saccharobutylicum, and hence has potential commercial application.