The Ability of Bacillus licheniformis Protease to Remove Bacillus cereus and Pseudomonas aeruginosa biofilm

Abstract

Microbial biofilms are active communities of microorganisms attached to a surface and surrounded by a self-produced matrix composed of extracellular polymeric substances, acting as a shield against desiccation, cleaning procedures and antimicrobial substances. No matter which biomolecule is most responsible in the matrix formation, all these extracellular polymeric substances can nevertheless be broken down with different enzymes leading to a disruption of the biofilm matrix and the removal of the biofilm. Enzyme treatments can be used to break down extracellular polymeric substances as an alternative when standard cleaning agents do not give satisfactory results in removing biofilms. The aim of the study was to analyze the activity of a protease from B. licheniformis against the biofilm formed by B. cereus and P. aeruginosa. Fluorescent microscopy and confocal laser scanning microscopy was performed in order to assess the effect of the enzyme on the biofilm structure and to characterize the biofilm formed by both microorganisms. The results show that the enzyme used was more active against the B. cereus biofilm matrix compared to the activity on the P. aeruginosa biofilm matrix.