ABSTRACT
Growth and metabolic activity of several new, human origin isolates of Bifidobacterium strains were investigated. All tested bifidobacteria strains were grown well on the native soymilk medium without any additional nutrients. The fermentation processes cultured with initial cell concentrations in 105 -107 cfu/ml resulted in 108 cfu/ml after 8-12 h of incubation in soymilk, and were kept viable up to the end of fermentation (48 h). Volumetric productivities of B. bifidum B3.2, B. bifidum B7.1 and B. breve B9.14 were 1.6 × 10¹° cfu/L.h, 4.5 × 10¹° cfu/L.h and 7.6 × 109 cfu/L.h, respectively, whereas these values of B. lactis Bb-12 and B. longum Bb-46 probiotic strains were 2.7 × 109 cfu/L.h and 1.0 x 10¹° cfu/L.h. The α-galactosidase activities were also detected in the intracellular fraction of the disrupted cells. Productions of lactic and acetic acids were in the range of 23-60 mmol/L and 2.4-5.6 mmol/L, respectively. Molar ratios of acetate to lactate in all tested strains varied from 0.05-0.1 that are very promising for further technological development of probiotic fermented soy-based food products.