T WENTY-THREE different bacterial and fungal isolates were grown and screened for their capability to transform soy glycosides to their aglycone forms with higher titer of antioxidant activity compared to unfermented soy flour. Most of the bacterial isolates showed higher amounts of daidzein than of genistein, which are the aglycone products of daidzin and genistin. After fermentation of soybean flour using bacterial and fungal isolates, the content of isoflavone aglycones varied from 0.0 to 431.89 µg/g compared to unfermented autoclaved soybean flour. Extracellular β-glucosidase activity was ranged from 1.22 to 11.56 mU/mL and 0.3-534.3 U/mL for bacterial and fungal isolates, respectively, while, bacterial cell-bound β-glucosidase ranged from 44.72 to 128.89 mU/mL. Most of the bacterial isolates more efficiently transformed daidzin and genistin into the aglycones than fungal isolates. Among the tested bacterial isolates, the most potent one was selected, characterized according to the morphological and 16S rDNA sequence analysis and identified as Bacillus licheniformis NRC24.

EIGHT lactic acid bacterial (LAB) isolates were obtained from food and non-food sources and identified by 16S rRNA gene sequence analysis. Based on the sequencing results, the isolates belong to two species of lactobacilli, Lactobacillus plantarum and L. rhamnosus. These strains were then compared with a reference strain, Lactobacillus casei, to assess various probiotic properties, such as haemolytic activity, histamine formation ability, stress tolerance under certain stress conditions, antibiotic susceptibility and in vitro adhesion ability. Moreover, bile salt hydrolase (BSH) activity was evaluated both qualitatively and quantitatively. The results showed that none of the isolates demonstrated any haemolytic activity or histamine formation. The isolated strains were also tolerant to acidic and alkaline conditions (pH 2.5, 3.5 and 9) for 3 and 6 h, as well as osmotic (3 M NaCl) and heat (55 and 70°C) stress, but were more responsive to oxidative and bile stress. The bacterial isolates also expressed high amounts of BSH, ranging from 90 to 142 U/mg in active cells, compared to L. casei (74 U/mg), which may be useful in cholesterol reduction. All bacterial isolates were resistant to vancomycin and susceptible to amoxicillin, cloxacillin and penicillin. All isolates were also highly hydrophobic (>70%), indicating that they are not easily flushed from the intestines.