title: Immobilized Clostridium acetobutylicum P262 Mutants for Solvent Production.
abstract: The production of acetone, butanol, and ethanol by two immobilized, sporulation-deficient (spo) Clostridium acetobutylicum P262 mutants which were held in the solventogenic phase was investigated. The spoA2 mutant, which was an early-sporulation mutant and did not form a forespore septum, produced higher solvent yields than did the spoB mutant which was a late-sporulation mutant and was blocked at a stage after forespore septum formation. The spoA2 mutant was also granulose and capsule negative. In a conventional batch fermentation, the wild-type strain produced 15.44 g of solvents per liter after 50 h at a productivity of 7.41 g of solvents per liter per day. The spoA2 mutant produced 15.42 g of solvents per liter at a productivity of 72.4 g of solvents per liter per day, with a retention time of 2.4 h in a continuous immobilized cell system employing a fluidized bed reactor. This represents a major advance, since the immobilization of wild-type cells showed similar increases in productivity but a ca. fivefold reduction in final product concentrations.
authors.affiliation: Department of Microbiology, University of Cape Town, Rondebosch, 7700, South Africa.
authors.forename: S T
authors.initials: ST
authors.lastname: Largier
authors.forename: S
authors.initials: S
authors.lastname: Long
authors.forename: J D
authors.initials: JD
authors.lastname: Santangelo
authors.forename: D T
authors.initials: DT
authors.lastname: Jones
authors.forename: D R
authors.initials: DR
authors.lastname: Woods