Ashley Steere, ± John Warner+, Silvana Andreescu*
Department of Biomolecular Science, Clarkson University, Potsdam , NY 13699
Phenol and phenolic derivatives are major industrial and agricultural by-products that can be found in soil and surface waters. Due to their toxicity and harmful effects, phenolic compounds are among United States Environmental Protection Agency (US-EPA) priority contaminants. In this presentation, we report the use of alginate-chitosan microcapsules with immobilized enzyme for the removal of phenol from wastewaters. Both chitosan and alginate are nontoxic natural biopolymers, making them an excellent choice for environmental applications. The method is based on the combined use of enzymatic oxidation of the substrate and subsequent adsorption of the reaction product onto the corresponding biopolymer. The enzyme (tyrosinase) was immobilized into the core of the microcapsule. A second polymeric layer was then used to prevent enzyme leaching, stabilize the capsule and trap the reaction product inside the core. Six types of microcapsules were studied for their phenol degrading properties. The capsules were tested for their stability, enzyme leaking, reproducibility and long-term functionality and storage conditions. The capsules with a chitosan core/alginate shell that were additionally crosslinked with glutaraldehyde showed superior phenol degradation properties, faster removal and greater reproducibility from one capsule to another. Freezing the capsules in water caused a significant decrease in their ability to degrade phenol, most likely the result of freeze fracturing of the capsules. Whereas, capsules stored at room temperature also showed a decrease in phenol removal as compared to capsules stored between 2-8 degrees Celsius. This effect was most likely due to inactivation of the tyrosinase because of temperature.
±Class of 2007, Elmira College, Biology-Chemistry, participant in NSF-REU program in Environmental Science and Engineering, Clarkson University, 2006
+ Class of 2008, Clarkson University, Chemistry and Biomolecular Science
*Project Mentor and Associate Professor of Chemistry, Clarkson University (eandrees@clarkson.edu)