Involved in biofilm formation (PubMed:18978066, PubMed:21742882). Self-polymerizes and forms a layer on the surface of biofilms that confers hydrophobicity to the biofilm (PubMed:22571672, PubMed:23904481). The layer is stable and capable of resistance to high mechanical force compression (PubMed:28701036). Required for complex colony architecture (PubMed:18978066). May function synergistically with exopolysaccharides and TasA amyloid fibers to facilitate the assembly of the biofilm matrix (PubMed:21742882). Forms polymers. Localizes to the biofilm matrix (PubMed:22571672, PubMed:23904481). Forms a distinct layer at biofilm surfaces (PubMed:23904481). Localization to the matrix is exopolysaccharide-dependent (PubMed:22571672). Up-regulated by DegU and Spo0A. Repressed by AbrB. Overall loss in complex colony architecture and lack of fruiting body-like structures (PubMed:18978066). Disruption of the gene results in the loss of surface repellency and alters the biofilm surface microstructure (PubMed:22571672). Belongs to the BslA/BslB family.