The strains of L. plantarum B1–6 was prepared for two successive transfers in de Man–Rogosa and Sharp broth (MRS, pH 6.2). The microorganism was propagated in MRS at 37 °C for 24 h,and the activated culture was again inoculated into MRS broth at 37 °C for 16 h. The cells were harvested by centrifugation at 5000 g at 4 °C for 10 min, and washed twice with sterilized physiological saline and then resuspended in sterilized physiological saline. This cells suspension was ready to serve as inoculum for soy whey fermentation.