Biochemical characteristics and fermentation of glucose and starch by rabbit caecal strains of Bifidobacterium globosum.

Two strains of Bifidobacterium globosum were isolated from caecal contents of rabbits in a search for potential probiotics. Both strains fermented glucose, galactose, pentoses, maltose, raffinose and starch. Common coccidiostats (monensin, salinomycin) and antimicrobial growth promotors (avoparcin, bacitracin, nitrovin, virginiamycin) supplied at 10 mg/L inhibited their growth in cultures with glucose. Fermentation parameters of bifidobacteria on glucose and starch differed. More formate and ethanol and less lactate were produced during growth on glucose than during growth on starch. When growing on starch, the two strains of bifidobacteria produced 1 mol lactate per 5.6 and 5.7 mol acetate, respectively. Corresponding values during growth on glucose were 17.3 and 8.4 mol of acetate per mol of lactate. Starch-grown cells accumulated more saccharides than cells grown on glucose (1.48 vs. 0.41 and 3.12 vs. 1.18 mmol glucose units per 1 g of dry matter, respectively).