REACTION KINETICS OF VERSATILE PEROXIDASE FOR THE DEGRADATION OF LIGNIN COMPOUNDS

The H2O2-dependent degradation of adlerol by a crude versatile peroxidase from Bjekandera adusta, a new ligninolytic enzyme, was investigated. Adlerol is a non-phenolic beta -O-4 dimer whose structural architecture represents the most abundant unit of the valuable renewable biopolymer lignin. Lignin removal plays a key role in utilizing lignocellulosic biomass in biorefineries. Steady-state analyses in the mu L scale showed saturation kinetics for both, H2O2 and adlerol with quite sensitive response to H2O2. This was characterized through slow transient states (lag phases) prior steady-state and were enhanced by increasing H2O2 concentration. The major reason for such phenomena was found to be an accumulation of compound III (E super( III)) via reaction of compound II (E super( II)) with H2O2; instead with adlerol to the enzyme's ground state E super( 0) in order to restart another catalytic cycle. As result, the enzyme deviated from its normal catalytic cycle. A corresponding threshold was determined at greater than or equal to 50 mu M H2O2 and an adlerol to H2O2 ratio of 15:1 for the given conditions.