STICKY BUSINESS: IMPACT OF ACID-BASE INTERACTIONS ON THE SURFACE POTENTIAL OF MICROORGANISMS

Many studies have shown that bacterial adhesion to mineral surfaces is a function of aqueous geochemistry and mineral surface charge. Studies have also shown that the metabolic state of the organism influences the strength of adhesion to a surface. In this research we document the influence of mineral composition and surface charge on bacterial adhesion and proliferation. Two strains of non-pathogenic bacteria (Enterococcus faecalis and Escherichia Coli) were grown in Tryptic Soy broth in the presence and absence of microspheres of different composition (glass, polystyrene, and iron). Bacterial populations were counted and growth rates were normalized to surface area to identify any influence of the microsphere composition on bacterial proliferation. Microspheres with attached bacteria were used to make colloid probes and the outer surfaces of the bacteria were analyzed via force spectroscopy. Our results indicate slight differences in bacterial surface properties related to microsphere composition as determined by force-separation distance profiles collected in aqueous media. Bacterial growth rates were significantly affected by microsphere composition.