The resistance of polylactide to biodegradation and the physical properties of this polymer can be controlled by adjusting the ratio of L-lactic acid to D-lactic acid. Although the largest demand is for the L enantiomer, substantial amounts of both enantiomers are required for bioplastics. We constructed derivatives of Escherichia coli W3110 (prototrophic) as new biocatalysts for the production of D-lactic acid. These strains (SZ40, SZ58, and SZ63) require only mineral salts as nutrients and lack all plasmids and antibiotic resistance genes used during construction. D-Lactic acid production by these new strains approached the theoretical maximum yield of two molecules per glucose molecule. The chemical purity of this D-lactic acid was approximately 98% with respect to soluble organic compounds. The optical purity exceeded 99%. Competing pathways were eliminated by chromosomal inactivation of genes encoding fumarate reductase (frdABCD), alcohol/aldehyde dehydrogenase (adhE), and pyruvate formate lyase (pflB). The cell yield and lactate productivity were increased by a further mutation in the acetate kinase gene (ackA). Similar improvements could be achieved by addition of 10 mM acetate or by an initial period of aeration. All th...Continue Reading
Genetic improvement of Escherichia coli for ethanol production: chromosomal integration of Zymomonas mobilis genes encoding pyruvate decarboxylase and alcohol dehydrogenase II.
Versatile insertion plasmids for targeted genome manipulations in bacteria: isolation, deletion, and rescue of the pathogenicity island LEE of the Escherichia coli O157:H7 genome
Regulation of RssB-dependent proteolysis in Escherichia coli: a role for acetyl phosphate in a response regulator-controlled process
The steady-state internal redox state (NADH/NAD) reflects the external redox state and is correlated with catabolic adaptation in Escherichia coli
High-performance liquid chromatographic assay of (+/-)-lactic acid and its enantiomers in calf serum
D-Lactate dehydrogenase gene (ldhD) inactivation and resulting metabolic effects in the Lactobacillus johnsonii strains La1 and N312
Biosynthetic burden and plasmid burden limit expression of chromosomally integrated heterologous genes (pdc, adhB) in Escherichia coli
Acetate metabolism in a pta mutant of Escherichia coli W3110: importance of maintaining acetyl coenzyme A flux for growth and survival
Chromosomal integration of heterologous DNA in Escherichia coli with precise removal of markers and replicons used during construction
Metabolic analysis of Escherichia coli in the presence and absence of the carboxylating enzymes phosphoenolpyruvate carboxylase and pyruvate carboxylase.
Physically crosslinked dextran hydrogels by stereocomplex formation of lactic acid oligomers: degradation and protein release behavior
Engineering a homo-ethanol pathway in Escherichia coli: increased glycolytic flux and levels of expression of glycolytic genes during xylose fermentation
Recombinant Escherichia coli engineered for production of L-lactic acid from hexose and pentose sugars
Efficient homolactic fermentation by Kluyveromyces lactis strains defective in pyruvate utilization and transformed with the heterologous LDH gene
Flux through citrate synthase limits the growth of ethanologenic Escherichia coli KO11 during xylose fermentation.
MUTANT OF SALMONELLA TYPHIMURIUM DEFICIENT IN THE CARBON DIOXIDE-FIXING ENZYME PHOSPHOENOLPYRUVIC CARBOXYLASE.
Global gene expression analysis of glucose overflow metabolism in Escherichia coli and reduction of aerobic acetate formation
Investigating the effectiveness of DNA microarray analysis for identifying the genes involved in l-lactate production by Saccharomyces cerevisiae
Strain improvement of Sporolactobacillus inulinus ATCC 15538 for acid tolerance and production of D-lactic acid by genome shuffling
Biotechnological production of enantiomeric pure lactic acid from renewable resources: recent achievements, perspectives, and limits
Metabolic engineering of Escherichia coli for biotechnological production of high-value organic acids and alcohols
Continuous D-lactic acid production by a novel thermotolerant Lactobacillus delbrueckii subsp. lactis QU 41
Reactions upstream of glycerate-1,3-bisphosphate drive Corynebacterium glutamicum (D)-lactate productivity under oxygen deprivation
ATP limitation in a pyruvate formate lyase mutant of Escherichia coli MG1655 increases glycolytic flux to D-lactate
Production of D-lactic acid from sugarcane molasses, sugarcane juice and sugar beet juice by Lactobacillus delbrueckii
Improvement of D-lactate productivity in recombinant Escherichia coli by coupling production with growth
Homofermentative production of D-lactic acid from sucrose by a metabolically engineered Escherichia coli
Increasing reducing power output (NADH) of glucose catabolism for reduction of xylose to xylitol by genetically engineered Escherichia coli AI05
Genome-wide analysis of redox reactions reveals metabolic engineering targets for D-lactate overproduction in Escherichia coli
Creation of a cellooligosaccharide-assimilating Escherichia coli strain by displaying active beta-glucosidase on the cell surface via a novel anchor protein
Deletion of genes encoding cytochrome oxidases and quinol monooxygenase blocks the aerobic-anaerobic shift in Escherichia coli K-12 MG1655
Genetic tool development for a new host for biotechnology, the thermotolerant bacterium Bacillus coagulans
Functional replacement of the Escherichia coli D-(-)-lactate dehydrogenase gene (ldhA) with the L-(+)-lactate dehydrogenase gene (ldhL) from Pediococcus acidilactici.
Genetically engineered wine yeast produces a high concentration of L-lactic acid of extremely high optical purity
Characterization of XynC from Bacillus subtilis subsp. subtilis strain 168 and analysis of its role in depolymerization of glucuronoxylan
Pyruvate formate lyase and acetate kinase are essential for anaerobic growth of Escherichia coli on xylose
Quinone-dependent D-lactate dehydrogenase Dld (Cg1027) is essential for growth of Corynebacterium glutamicum on D-lactate
Efficient production of l-lactic acid by an engineered Thermoanaerobacterium aotearoense with broad substrate specificity
Engineering the metabolism of Escherichia coli W3110 for the conversion of sugar to redox-neutral and oxidized products: homoacetate production
Metabolic engineering for production of biorenewable fuels and chemicals: contributions of synthetic biology
Diammonium phosphate stimulates transcription of L-lactate dehydrogenase leading to increased L-lactate production in the thermotolerant Bacillus coagulans strain
Strategies used for genetically modifying bacterial genome: site-directed mutagenesis, gene inactivation, and gene over-expression
Biosyntheic transformtions are multi-step, enzyme-catalyzed processes where substrates are converted into more complex products in living organisms. Simple compounds are modified, converted into other compounds, or joined together to form macromolecules. Discover the latest research on biosynthetic transformations here.