Activity analyses of extracellular laccase enzymes induced by 2,5-xylidine and Kraft lignin

CHED 1090

Ryan C. McDonald, mcdonaldr@etown.edu and Leah R. Eller, ellerl@etown.edu. Department of Chemistry & Biochemistry, Elizabethtown College, One Alpha Dr, Musser 222, Elizabethtown, PA 17022
Redox enzymes present a “green” method of dealing with many environmental remediation problems. Enzymes produced by the addition of inducing agents often differ in activity than constitutive enzymes. Ganoderma tsugae, collected locally from Elizabethtown, PA, was isolated on potato dextrose agar and used to inoculate malt extract broth liquid cultures. 2,5-xylidine and Kraft lignin were added to the growth media as inducers. Laccase enzymes, of the blue copper family of proteins, were isolated and purified from these cultures. The activity of these enzymes with regard to optimum pH, growth time and growth medium was compared to the corresponding activity of constitutive enzymes using UV-visible spectroscopy. The ability of the induced enzymes to degrade persistent organic pollutants was then tested. Various aromatic compounds, halogenated and non-halogenated, were exposed to the induced enzymes and monitored for degradation by gas chromatography, GC-MS spectrometry, and NMR spectroscopy.