The effect of metal salts on the activity of the phenol oxidase complex enzymes of bacteria of the genus Azospirillum

Recently, much attention has been paid to the development of technologies for biodegradation of organopollutants and the search for promising biodestructors. The environmental accumulation of lignin-like compounds and synthetic dyes poses a huge threat not only to ecosystems and biodiversity, but also to human health. Phenol oxidases are enzymes with broad substrate specificity, with oxidizing ability towards various polyphenols and aromatic amines. Therefore the use of phenol oxydases as bioremediation agents is promising due to their unique catalytic properties. In this work we present the results of a study of the effect of metal ions on the activity of the azospirilla phenol oxidase complex. It was demonstrated that extracellular laccases of lignin- and Mn-peroxidases of strains Azospirillum baldaniorum Sp245 and Azospirillum brasilense SR80 are quite stable in the presence of the studied metal salts. The enzymatic activity decreased and the effectiveness of the organopollutants’ biodegradation efficacy was inhibited in the presence of Zn2+ ions. The laccase and lignin-peroxidase activity induced by copper ions positively correlated with the ability of lignin degradation by azospirillum. Analysis of the obtained data showed that inhibitors and inducers of authentic extracellular phenol oxidases of both fungi and bacteria are typical for azospirillum enzymes.