Potential application of catalase-peroxidase from Comamonas terrigena N3H in the biodegradation of phenolic compounds

Comamonas terrigena N3H is a gram-negative rod-shaped bacterium that was is olated from contaminated soil in Slovakia. This bacterium showed remarkable biodegradation properties. We investigated the expression and functioning of two catalase isozymes in this bacterium. The typical catalase could be i nduced by cadmium ions, whereas the catalase-peroxidase enzyme was constitu tively expressed. Since C. terrigena lacks the key enzyme for complete degr adation of phenols (phenolhydroxylase), we analysed the possible removal of phenol by the two catalases of this bacterium. Addition of phenol to the c ulture medium led to increased expression of the catalase-peroxidase. Apply ing oxidative stress prior to phenol administration markedly induced the ex pression of the typical catalase, irrespective of the nature of the added a gent. Thus, the rate of phenol degradation is rather reduced under these co nditions, while growth of the cells is not impaired. We concluded that phen ol peroxidation in C. terrigena can be largely attributed to the action of a catalase-peroxidase. The potential application of this enzyme in the remo val of phenol from the environment is discussed.