Abstract:In order to improve the biological activity and utilization of soybean isoflavone，the target strain producing β-glucosidase was screened from human lactic acid bacteria preserved in the laboratory in a special medium containing aescin and iron citrate.The transformation ability of soybean isoflavone was determined by high performance liquid chromatography and the water holding capacity，acid production rate and the number of viable bacteria in the end of fermentation were analyzed.The results showed that among the 12 target strains screened out from 140 strains of lactic acid bacteria，strain 58 and strain m91 had the strongest ability to produce soybean isoflavone aglycones with the total amount of 59.64 mg/L and 58.06 mg/L，respectively，which were more than 8 times of that of the original soybean milk，significantly higher than that of other lactic acid bacteria （P＜0.05）.The results showed that the water holding capacity of strain 58 was 35.10 %，the number of viable bacteria was 8.78 lg（CFU/mL），it took 11.50 h to reach the end of fermentation，and the acid production rate was fast.By 16S rDNA sequencing and phylogenetic analysis，the optimal strain 58 was Lactobacillus plantarum.