During bacterial adhesion, the pH between the bacterial and adhering surfaces can vary due to the charge-regulation effect. This local pH can increase or decrease from that of the bulk solution, depending on the acid/base functional groups present on the two surfaces. In this study, we demonstrate how bacteria can alter the sorption and bioavailability of ionizable substrates via utilization of the charge-regulation effect.  We studied three different growth substrates – benzoic acid, ethylbenzene, and benzylamine – which exhibit acid, neutral, and basic functionalities, respectively. Using these growth substrates, we explored how bacterial adhesion altered their sorption and bioavailability with three GACs, including a baseline GAC, a weak-base treated GAC, and a quaternary amine (strong-base) treated GAC.  Zeta potential analysis demonstrated that the baseline carbon surface was acidic in nature while the treated carbons contained basic functional groups.  Substrate sorption on the GACs was a strong function of pH and this directly affected the bioavailability of the different growth substrates on the three different GACs.<br/> <br/>Here, we will demonstrate through experimental and numerical results how the charge-regulation effect induces changes in local pH during bacterial adhesion, which in turn alters the sorption and bioavailability of ionizable growth substrates. Overall, these findings have implications for the bioavailability of ionizable substrates at surfaces, whether sorbed or in solid form, and understanding of this effect can lead to more effective selection and design of absorbents for specific applications.<br/>

Bacterially-induced changes in the sorption and bioavailability of ionizable substrates during adhesion due to the charge-regulation effect

254th National Meeting (2017)

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