Biofilm surface layer protein A (BslA) is a surface-active biofilm protein in a soil bacterium called, Bascillus Subtilis. This Biofilm adheres to surface substrates in plant roots, forms an extremely hydrophobic layer and protects the plant against external threats such as microbes. If, however it is deposited onto human tissue surfaces it can cause chronic infections. Thus, studying this biofilm’s extraordinary mechanical stability and structure can help with developing new concepts for molecular design of biomaterials. In this talk results from Sum Frequency Generation (SFG) Spectroscopy, an interface-specific technique, to study BslA and its mutants at the air/water interface are reported. SFG was used to better understand which residues in this protein play a crucial role in forming such a unique biofilm structure.