title: Clostridium acetobutylicum Mutants That Produce Butyraldehyde and Altered Quantities of Solvents.
abstract: Spontaneous mutants of Clostridium acetobutylicum NRRL B643 that were resistant to allyl alcohol (AA) were selected and characterized. These mutants contained 10- to 100-fold reduced activities of butanol and ethanol alcohol dehydrogenase. The AA mutants formed two groups and produced no ethanol. Type 1 AA mutants produced significant amounts of a new solvent, butyraldehyde, and contained normal levels of the coenzyme A-dependent butyraldehyde dehydrogenase (BAD). Type 2 AA mutants produced no significant butyraldehyde and lower levels of all solvents, and they contained 45- to 100-fold lower activity levels of BAD. Following ethyl methanesulfonate mutagenesis, low-acid-producing (Acid) mutants were selected and characterized as superinduced solvent producers, yielding more than 99% of theoretical glucose carbon as solvents and only small amounts of acetate and butyrate. Following ethyl methanesulfonate mutagenesis, 13 sporulation-negative (Spo) mutants were characterized; and 3 were found to produce only butyrate and acetate, a minor amount of acetone, and no alcohols. These Spo mutants contained reduced butanol dehydrogenase activity and no BAD enzyme activity. The data support the view that the type 2 AA, the Acid, and the Spo mutants somehow alter normal regulated expression of the solvent pathway in C. acetobutylicum.
authors.affiliation: Department of Microbiology, University of Minnesota, Minneapolis, Minnesota 55455.
authors.forename: P
authors.initials: P
authors.lastname: Rogers
authors.forename: N
authors.initials: N
authors.lastname: Palosaari