We are interested in understanding how biopolymers change their size and shape as a function of solution chemistry. This work is being done in collaboration with Dr. Kevin Wilkinson of the CABE group at the University of Geneva.
The biopolymers produced by soil microorganisms are of most interest to us. These macromolecules are one component of natural organic matter. The fate of toxic compounds and nutrients in the environment depends on the association of these compounds with the natural organic matter that is present. Many more references on this subject can be found at the CABE webpage.
The bacterial polymers are difficult to purify and work with. Therefore, we began by studying a model biopolymer, xanthan. Xanthan is of similar size and charge as the polymers present on the bacteria. We studied the conformation of xanthan as a function of salt concentration. Here are some preliminary results.
When no salt is present, xanthan molecules are highly rigid and elongated. When salt is added, the polymer becomes more flexible and can coil and bend.