Changes in biofilm formation due to the B. subtilis Bs916 and ΔgltB mutants in MSgg culture medium with 20 μg/mL Congo Red and 10 μg/mL Coomassie brilliant blue.

(1) B. subtilis Bs916 biofilm was dense and solid with clear lines. In contrast, the ΔgltB mutant formed an uneven biofilm with an irregular shape. (2) The net weight of the ΔgltB mutant biofilm was more than three times less than the net weight of the WT B. subtilis Bs916 biofilm.