Bioconversion of Isoflavones and the Probiotic Properties of the Electroporated Parent and Subsequent Three Subcultures of Lactobacillus fermentum BT 8219 in Biotin-Soymilk

This study was aimed at an evaluation of the potential inheritance of electroporation effects on Lactobacillus fermentum BT 8219 through to three subsequent subcultures, based on their growth, isoflavone bioconversion activities, and probiotic properties, in biotin-supplemented soymilk. Electroporation was seen to cause cell death immediately after treatment, followed by higher growth than the control during fermentation in biotin-soymilk (P less than 0.05). This was associated with enhanced intracellular and extracellular β-glucosidase specific activity, leading to increased bioconversion of isoflavone glucosides to aglycones (P less than 0.05). The growing characteristics, enzyme, and isoflavone bioconversion activities of the first, second, and third subcultures of treated cells in biotin-soymilk were similar to the control (P greater than 0.05). Electroporation affected the probiotic properties of parent L. fermentum BT 8219, by reducing its tolerance towards acid (pH 2) and bile, lowering its inhibitory activities against selected pathogens, and reducing its ability for adhesion, when compared with the control (P less than 0.05). The first, second, and third subcultures of the treated cells showed comparable traits with that of the control (P greater than 0.05), with the exception of their bile tolerance ability, which was inherited to the treated cells of the first and second subcultures (P less than 0.05). Our results suggest that electroporation could be used to increase the bioactivity of biotin-soymilk via fermentation with probiotic L. fermentum BT 8219, with a view towards the development of functional foods.