The objective of this research is to evaluate the possibility of enhanced metal precipitation inside algal biofilms. The pH environment surrounding microorganisms growing in biofilms is frequently different than the environment of the bulk liquid because products of metabolic reactions are limited in their ability to diffuse out of the biofilm. This occurs with algal biofilms, in which CO2 utilization during photosynthesis results in an increase in the pH. The pH inside algal biofilms can be several units higher than the pH of the surrounding liquid. This higher pH favors removal of metals by precipitation and possibly adsorption. Laboratory studies were conducted in which biofilms of Cladophora glomerata were grown in buffered nutrient media. Copper or nickel was added to the media to study short term metal removals. Experimental results were compared to predictions of solubility based on a theoretical model of pH inside algal biofilms. Results provide evidence to support the theory that higher internal pH can result in greater metal removal by the biofilms.

Denaturation of oxidized cytochrome c (cyt c) adsorbed to a hydrophilic fused silica surface was studied by UV‐VIS attenuated total reflection (ATR) spectroscopy using a multiple optical pass system newly developed by this lab. Cyt c surface adsorption at neutral pH gave an adsorption equilibrium constant of Ka = 2 × 105 M−1 and a surface coverage at 63% of a monolayer saturation. Protein unfolding by acid denaturation was studied by equilibrating surface bound cyt c with acid buffers ranging in pH from 5 to 2. Protein orientation and surface coverage were calculated based on a theoretical model developed in previous work. The average heme tilt angle (44°) was found to be independent of pH, implicating protein‐surface interactions as the dominant factor governing adsorption. A non‐random molecular orientation distribution of cyt c on the surface was observed, providing further support for the dominance of protein‐surface interactions. It was shown that when denaturing acid buffers were removed and replaced with a neutral buffer cyt c refolded, assuming their original conformation. The combination of unique, yet applicable, science and laboratory skills involved in this project had a tremendous impact on the authors‘ undergraduate curriculum, making it ideal for capstone project development.