cKlebsiella pneumoniae is considered a good host strain for the production of 2,3-butanediol, which is a promising platform chemical with various industrial applications. In this study, three genes, including those encoding glucosyltransferase (wabG), lactate dehydrogenase (ldhA), and pyruvate formate-lyase (pflB), were disrupted in K. pneumoniae to reduce both its pathogenic characteristics and the production of several by-products. In flask cultivation with minimal medium, the yield of 2,3-butanediol from rationally engineered K. pneumoniae (⌬wabG ⌬ldhA ⌬pflB) reached 0.461 g/g glucose, which was 92.2% of the theoretical maximum, with a significant reduction in by-product formation. However, the growth rate of the pflB mutant was slightly reduced compared to that of its parental strain. Comparison with similar mutants of Escherichia coli suggested that the growth defect of pflB-deficient K. pneumoniae was caused by redox imbalance rather than reduced level of intracellular acetyl coenzyme A (acetyl-CoA). From an analysis of the transcriptome, it was confirmed that the removal of pflB from K. pneumoniae significantly repressed the expression of genes involved in the formate hydrogen lyase (FHL) system.

2,3-Butanediol (2,3-BD) is a glycol widely used as a reagent in a number of chemical syntheses. In addition to its applications in plastics, solvent, and antifreeze preparations, it could also be converted to 1,3-butadiene (for synthetic rubber), diacetyl (flavoring agent), or methyl ethyl ketone (liquid fuel additive) or to precursors of polyurethane (8). Interest in microbial production of 2,3-butanediol has been increasing recently due to the extensive industrial applications of this product (3). This colorless and odorless liquid with a high boiling point and a low freezing point is a potential valuable fuel additive (5). Klebsiella pneumoniae KCTC 2242 is a Gram-negative, nonmotile, encapsulated, facultative anaerobic, rod-shaped bacterium. Although K. pneumoniae is a pathogenic microorganism, much research on 2,3-butanediol production is going on (2, 6). Whole-genome sequencing and transcriptome analysis were carried out not only to compare gene data with that of the already published genes of K. pneumoniae NTUH-K2044 (NCBI accession number AP006725), K. pneumoniae 342 (NCBI accession number CP000964), and K. pneumoniae MGH 78578 (NCBI accession number CP000647) but also to discover the characteristics and genomic level of K. pneumoniae KCTC 2242.Genomic DNA isolated using an overnight culture of strain KCTC 2242 and a DNeasy blood and tissue kit (Qiagen) was sequenced by 454 GS FLX Titanium pyrosequencing (Roche), following the manufacturer's instructions, with 25ϫ coverage (4). Then, the 501,755 reads generated, with a length of 129,696,091 bp, were assembled using a GS De Novo assembler (version 2.3; Roche). The N50 contig was 146,341 bp in length, and largest contig assembled was 358,873 bp. This assembly generated 67 large contigs (Ͼ500 bp), with a length of 5,394,883 bp. A total of 480,845 reads (95.83% of the total) were assembled into 10 scaffolds composed of 99 contigs, with a length of 5,426,912 bp. The N50 scaffold was 2,943,199 bp, and the average length of the scaffolds was 542,691 bp.The order of scaffolds was determined by a similarity search among published references and confirmed by PCR size checks. Gaps both within and between scaffolds can be closed by longrange PCR (using MG Taq-HF DNA polymerase; Macrogen, Seoul, South Korea) and subsequent Sanger sequencing using an ABI 3730XL capillary sequencer. The sequences from ABI 3730XL sequencing and scaffolds were completely assembled into one circular genome by the use of Phred/Phrap/Consed software (1) and annotated with the Prokaryote Genomes Automatic Annotation Pipeline (PGAAP) (7).The complete genome is composed of a circular chromosome of 5,259,571 bp (57.6% GC content), which includes 5,035 coding genes, 87 tRNA genes, and 25 rRNA genes. A total of 4,923 coding genes (97.77% of the total) have putative functions assigned on the basis of annotation. Plasmid pKCTC2242 contains 202,852 bp (50.2% GC content; 229 coding sequences [CDS]). A transcriptome experiment using KCTC 2242 and the Roche FLX system was performed to improve its genom...

e This is the first complete genome sequence of the Enterobacter aerogenes species. Here we present the genome sequence of E. aerogenes KCTC 2190, which contains 5,280,350 bp with a G ؉ C content of 54.8 mol%, 4,912 protein-coding genes, and 109 structural RNAs.2,3-Butanediol is a very important chemical because of its wide commercial applications in the manufacture of butadiene (6) and butan-2-1, aviation fuels, fumigants, moistening agents, and plasticizers and its use as an antifreeze agent and in liquid fuel (2, 4) and as an octane booster (1). 2,3-Butanediol can be produced from both hexose and pentose by several microorganisms, among them Klebsiella oxytoca, Bacillus polymyxa, Bacillus licheniformis, Bacillus subtilis, Aeromonas hydrophila, Serratia marcescens (3, 4), and Bacillus amyloliquefaciens (1). Enterobacter aerogenes, a facultative anaerobic bacterium, preferentially produces hydrogen under strictly anaerobic conditions (7) and becomes a butanediol producer with properties very similar to those of K. oxytoca when fermentation is stimulated by microaeration (9, 10). E. aerogenes KCTC 2190 was obtained from the Korean Collection for Type Culture (Daejun, South Korea).Genomic DNA isolated from an overnight culture of E. aerogenes strain KCTC 2190 by the use of a DNeasy blood and tissue kit (Qiagen) was sequenced by 454 GS FLX Titanium pyrosequencing (Roche), following the manufacturer's instructions, with 25ϫ coverage (5). Then, the 541,712 reads generated, with a length of 133,195,988 bp, were assembled using GS De Novo assembler (version 2.3; Roche). The N50 contig was 294,108 bp, and the largest contig assembled was 542,263 bp. This assembly generated 55 large (Ͼ500 bp) contigs, with a length of 5,243,714 bp. The 517,103 reads (95.45% of the total) were assembled into 11 scaffolds composed of 88 contigs, with a length of 5,243,714 bp. The N50 scaffold was 2,741,105 bp, and the average length of the scaffolds was 476,701 bp.The order of scaffolds was determined by a similarity search among published references and confirmed by a PCR size check. Gaps both within and between scaffolds can be closed by longrange PCR (using MG Taq-HF DNA polymerase; Macrogen, Seoul, South Korea) and subsequent Sanger sequencing using an ABI 3730 capillary sequencer. The sequences from ABI 3730XL sequencing and scaffolds were completely assembled into one circular genome using Phred/Phrap/Consed software and annotated with Prokaryote Genomes Automatic Annotation Pipeline (PGAAP) software (8).The complete genome is composed of a circular chromosome of 5,280,350 bp (54.8% G ϩ C content), including 4,912 coding genes, 84 tRNAs, and 25 rRNAs. A total of 3,824 coding genes (77.85% of the total) have putative functions assigned on the basis of annotation.We found the genes acetoin dehydrogenase (budC), acetolactate synthase (budB), and alpha-acetolactate decarboxylase (budA), a putative transcriptional regulator (budR), and a putative 3-hydroxybutyrate dehydrogenase (bdh), which is involved in the production of 2,3-butanediol...

eHere we report the full genome sequence of Klebsiella oxytoca KCTC 1686, which is used in production of 2,3-butanediol. The KCTC 1686 strain contains 5,974,109 bp with G؉C content of 56.05 mol% and contains 5,488 protein-coding genes and 110 structural RNAs.