Learn More
The genome sequence of the solvent-producing bacterium Clostridium acetobutylicum ATCC 824 has been determined by the shotgun approach. The genome consists of a 3.94-Mb chromosome and a 192-kb megaplasmid that contains the majority of genes responsible for solvent production. Comparison of C. acetobutylicum to Bacillus subtilis reveals significant local(More)
Integrational plasmid technology has been used to disrupt metabolic pathways leading to acetate and butyrate formation in Clostridium acetobutylicum ATCC 824. Non-replicative plasmid constructs, containing either clostridial phosphotransacetylase (pta) or butyrate kinase (buk) gene fragments, were integrated into homologous regions on the chromosome.(More)
A novel in vivo method of producing succinate has been developed. A genetically engineered Escherichia coli strain has been constructed to meet the NADH requirement and carbon demand to produce high quantities and yield of succinate by strategically implementing metabolic pathway alterations. Currently, the maximum theoretical succinate yield under strictly(More)
Enterohemorrhagic strains of Escherichia coli must pass through the acidic gastric barrier to cause gastrointestinal disease. Taking into account the apparent low infectious dose of enterohemorrhagic E. coli, 11 O157:H7 strains and 4 commensal strains of E. coli were tested for their abilities to survive extreme acid exposures (pH 3). Three previously(More)
The potential to produce succinate aerobically in Escherichia coli would offer great advantages over anaerobic fermentation in terms of faster biomass generation, carbon throughput, and product formation. Genetic manipulations were performed on two aerobic succinate production systems to increase their succinate yield and productivity. One of the aerobic(More)
Metabolic engineering studies have generally focused on manipulating enzyme levels through either the amplification, addition, or deletion of a particular pathway. However, with cofactor-dependent production systems, once the enzyme levels are no longer limiting, cofactor availability and the ratio of the reduced to oxidized form of the cofactor can become(More)
It has been suggested (L. H. Harris, R. P. Desai, N. E. Welker, and E. T. Papoutsakis, Biotechnol. Bioeng. 67:1-11, 2000) that butyryl phosphate (BuP) is a regulator of solventogenesis in Clostridium acetobutylicum. Here, we determined BuP and acetyl phosphate (AcP) levels in fermentations of C. acetobutylicum wild type (WT), degenerate strain M5, a(More)
Reactions requiring reducing equivalents, NAD(P)H, are of enormous importance for the synthesis of industrially valuable compounds such as carotenoids, polymers, antibiotics and chiral alcohols among others. The use of whole-cell biocatalysis can reduce process cost by acting as catalyst and cofactor regenerator at the same time; however, product yields(More)
An aerobic succinate production system developed by Lin et al. (Metab Eng, in press) is capable of achieving the maximum theoretical succinate yield of 1.0 mol/mol glucose for aerobic conditions. It also exhibits high succinate productivity. This succinate production system is a mutant E. coli strain with five pathways inactivated: DeltasdhAB,(More)
This short review covers metabolic pathways, genetics and metabolic engineering of 1,2-propanediol formation in microbes. 1,2-Propanediol production by bacteria and yeasts has been known for many years and two general pathways are recognized. One involves the metabolism of deoxyhexoses, where lactaldehyde is formed during the glycolytic reactions and is(More)