To study the mechanism of re-activation of Zymomonas mobilis pyruvate decarboxylase apoenzyme by its cofactors thiamin diphosphate and Mg2", cofactor-free enzyme was prepared by dialysis against I mM-dipicolinic acid at pH 8.2. This apoenzyme was then used in a series of experiments that included determination of: (a) the affinity towards one cofactor when the other was present at saturating co...

The production of ethanol by Zymomonas mobilis NRRL B-4286 was studied in fed-batch cultures. Initial percent (w/v) glucose, rate of feed, and quantity of 50%; (w/v) glucose feed were varied. Glucose inhibition of growth rate occurred at concentrations greater than 8% (w/) Feed was begun after 4 h incubation. Feed volume was ca. 36%; of starting batch volume to get ca. 10%; (w/v) ethanol at har...

Genome-scale model reconstruction represents a major tool in the field of Metabolic Engineering .This paper reports on a study about data integration issues in the process of genome-scale reconstruction of the metabolic model of the bacterium Zymomonas mobilis, a promising organism for bioethanol production. Data is retrieved from the Entrez Gene, KEGG, BioCyc and Brenda databases, and the seve...

Simultaneous saccharification and fermentation of dextrin£zed cassava starch to glucose and alcohol, respectively, were carried out by co-immobilized Zymomonas mobilis and immobilz'zed glucoamylase (IG). Calcium alginate-entrapped cells and IG (4 : 1 ratio) gave an alcohol productivity of 0.30 glgww cellslh in a batchfermentation process. For continuous fermentation, 54.3 gil alcohol was produc...

The Erwinia uredovora crtB, crtE, crtI, and crtY genes required for beta-carotene biosynthesis were introduced by conjugal transfer into an ethanol-producing bacterium, Zymomonas mobilis, and a phytopathogenic bacterium, Agrobacterium tumefaciens, in which no carotenoid is synthesized. The transconjugants of Z. mobilis and A. tumefaciens carrying these genes appeared as yellow colonies and prod...

The effects of temperature on the kinetic parameters kcat and Km, for three isolates of the highly conserved monomeric enzyme 3-phosphoglycerate kinase (PGK), were investigated in detail using a rapid automated kinetics apparatus. PGK was purified from the thermophilic bacterium Thermoanaerobacter sp. Rt8.G4 (optimum growth temperature 68 degrees C), the mesophile Zymomonas mobilis (optimum gro...