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Pentitol metabolism in Lactobacillus casei.
Journal of Bacteriology
|December 1, 1979
Summary
Lactobacillus casei metabolizes ribitol and xylitol through a unique pathway, producing ethanol, acetate, and lactate. Key enzymes involved in pentitol metabolism are not strictly regulated by glucose.
Area of Science:
- Microbiology
- Biochemistry
- Metabolic pathways
Background:
- Lactobacillus casei exhibits metabolic versatility.
- Pentitol utilization involves specific enzymatic pathways.
Purpose of the Study:
- Investigate the fermentation products of Lactobacillus casei grown on ribitol and xylitol.
- Elucidate the metabolic pathway and regulation of pentitol utilization in Lactobacillus casei.
Main Methods:
- Culturing Lactobacillus casei on ribitol and xylitol.
- Analyzing fermentation products (ethanol, acetate, lactate).
- Enzyme activity assays for key metabolic enzymes.
Main Results:
- Heterolactic fermentation producing ethanol, acetate, and mixed D-/L-lactate observed.
- Pentitols converted to ribulose 5-phosphate or xylulose 5-phosphate via unique enzymatic steps.
- Initial pentitol metabolism enzymes (pentitol:phosphoenolypyruvate phosphotransferase, penititol phosphate dehydrogenase) showed no stringent regulation by glucose or glycolytic intermediates.
Conclusions:
- Lactobacillus casei employs a distinct pathway for pentitol metabolism.
- The pentose pathway is crucial for metabolizing pentitol-derived intermediates.
- Enzyme regulation in this pathway is not tightly controlled by host glycolytic status.