Fig. 4

Verification of the effect of substrate balance on the biofilm of strains through congo red staining (A) and crystal violet test (B, C). The positive control was the S12 supplemented with 20 g/L sucrose (WT-S20), the negative control was the hasE knockout strain supplemented with 20 g/L sucrose (SE0-S20), and the experimental groups were SE3 strains induced with 0 g/L (SE3-0), 3 g/L (SE3-3), and 5 g/L (SE3-5) sucrose, respectively