title: Recombination-induced variants of Clostridium acetobutylicum ATCC 824 with increased solvent production.
abstract: Three sporulation-specific genes (orfA, sigE, sigG) from clostridium acetobutylicum ATCC 824 are arranged in a cluster, encoding the putative sigma E-processing enzyme, sigma E, and sigma sigma G respectively. When they were transformed into Clostridium acetobutylicum while on a plasmid functional in this organism, transformants did not survive. Three kinds of recombinations were then attempted with nonreplicative plasmids: duplication of orfA and sigE, replacement of all of the three genes, and inactivation of orfA. While the wild-type strain ceased to grow and produce solvents in batch cultures after approximately 24 h, mutant strains were isolated that showed sustained growth for a much longer time and produced a threefold increase in acetone and butanol in test tube cultures. In addition, one of the derived strains showed a significantly higher growth rate. Features of the restriction maps of the recombinants did not correlate with expected maps, indicating possible complications occurring during the recombination events.
authors.affiliation: Rice University, Department of Biochemistry and Cell Biology, Houston, TX 77005-1892, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wong
authors.forename: G N
authors.initials: GN
authors.lastname: Bennett
mesh_terms: D003013:Clostridium / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D010957:Plasmids; D012997:Solvents / Q000378:metabolism*; D013171:Spores, Bacterial; D014169:Transformation, Bacterial
chemical_list: D012997:Solvents