Extracellular dextranase activity produced by human oral strains of the genus Bifidobacterium.

Abstract

Three strains of anaerobic, dextranase-producing, gram-positive, rod-shaped bacteria were isolated from human dental plaque associated with root carious lesions. The isolates produced a molar ratio of acetate to lactate from glucose fermentation ranging from 1.1 to 1.9. Each strain also produced fructose-6-phosphate phosphoketolase. The isolates were identified as belonging to the genus Bifidobacterium, but from their carbohydrate fermentation patterns they did not appear to be strains of Bifidobacterium dentium. These microorganisms fermented high-molecular-weight dextrans. A partial characterization of the dextranase activity was included in this study and revealed an extracellular dextranase with a pH optimum of 7.1. Analysis of the dextran degradation products demonstrated the liberation of saccharides larger than 1 glucose unit. It was concluded that this enzyme used an endohydrolytic mode of dextran cleavage.

• Authors: A G Kaster, L R Brown
• Journal: Infection and immunity (Infect Immun) Vol. 42 Issue 2 Pg. 716-20 (Nov 1983) ISSN: 0019-9567 [Print] United States
• PMID: 6642650 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Dextranase
• Glucose

Topics

• Bifidobacterium (enzymology, genetics, isolation & purification)
• Carbohydrate Metabolism
• Dental Plaque (microbiology)
• Dextranase (genetics, metabolism)
• Fermentation
• Glucose (metabolism)
• Humans
• Kinetics
• Species Specificity