SURFACE PROPERTIES AND INTERACTIONS OF P. AERUGINOSA AND B. SUBTILIS WITH STAINLESS STEEL SS316 AND THEIR RELATION IN BIOFILM DEVELOPMENT

Abstract

Biofilm is ubiquitously found in a broad range of areas, such as in food, environmental, and biomedical fields, and is generally considered a major problem in the industries. It is important to determine the factors that influence cell adhesion onto surfaces that would initiate biofilm formation. In this study, several issues related to adhesion interaction between two model bacteria, P. aeruginosa and B. subtilis, and stainless steel are addressed.

This study showed the likelihood of P. aeruginosa and B. subtilis to establish biofilm and become persistent in the environment. Higher affinity was shown by P. aeruginosa when the adhesion force was quantified using AFM. . Spores of B. subtilis were also found to have higher adhesion force than its vegetative cells. This higher force has been found to be correlated with higher hydrophobicity and lower electrostatic repulsion interactions as explained by physicochemical analyses and DLVO and extended DLVO theories.

Elucidation on extracellular polymeric substances (EPS) produced by both bacterial strain showed that EPS produced by these two species were chemically dissimilar. Single Molecule Force Spectroscopy (SMFS) using AFM also revealed that the surface polymers on P. aeruginosa is more extended than B. subtilis which correlate to greater ability to stretch thus enhancing the adhesion interactions.