Biodegradation of Polyaromatics Synthesized by Peroxidase-Catalyzed Free-Radical Polymerization

Polymers formed from peroxidase-based free-radical polymerization reactions were characterized for rates of mineralization against lignin and humic acid controls. Degradation studies were carried out in soil systems over 202 days and cumulative net CO₂ was determined. Whereas mineralization of the humic acid and alkali lignin controls totaled ca. 20% at the end of the test exposure, there was essentially no net mineralization of the hydrolytic lignin control. Mineralization of the test samples totaled 5% for poly(p-ethylphenol) and 11% for poly(m-cresol). At the same time, mineralization of the poly(p-phenyl phenol) totaled 64%. Conversely, the readily biodegradable polymers cellulose and PHB reached values of 91 to 97% in less than 60 days. Our data suggest that the mineralization kinetics of the enzymatically derived polyaromatics mimic those of the naturally occurring heteropolymers.