Cellulose Production from Glucose Using a Glucose Dehydrogenase Gene (gdh)-Deficient Mutant of Gluconacetobacter xylinus and Its Use for Bioconversion of Sweet Potato Pulp(Genetics, Molecular Biology, and Gene Engineering)

概要

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A gene fragment encoding a putative pyrroloquinoline quinone glucose dehydrogenase (PQQ GDH) was cloned from a bacterial cellulose (BC)-forming acetic acid bacterium, Gluconacetobacter xylinus (=Acetobacter xylinum) strain BPR2001, which was isolated as a high BC producer when using fructose as the carbon source. A GDH-deficient mutant of strain BPR2001, namely GD-I, was then generated via gene disruption using the cloned gene fragment. Strain GD-I produced no gluconic acid but produced 4.1g・l^<-1> of BC aerobically in medium containing glucose as the carbon source. The ability of strain GD-I to convert glucose to BC was approximately 1.7-fold higher than that of the wild type. Strain GD-I was also able to produce 5.0g・l^<-1> of BC from a saccharified solution, which was derived from sweet potato pulp by enzymatic saccharification. Supplementation of ethanol during aerobic cultivation further increased the concentration of BC produced by strain GD-I to 7.0g・l^<-1>. The rate of conversion from glucose to BC under these cultivation conditions was equivalent to that of strain BPR2001 cultivated with fructose as the carbon source.
2005-04-25