G. hansenii strain was used in this study. This strain has been isolated from inoculums of a strain screened in homemade vinegar and then induced by high hydrostatic pressure treatment. It has a strong ability to produce BC more than three times as that of its initial strain. It was deposited as CGMCC3917 at China General Microbiological Culture Collection, Beijing, China and was maintained on glucose agar slants containing: 2% glucose (w/v), 0.5% yeast extract (w/v), 0.1% K2HPO4 (w/v), 1.5% MgSO4