Characteristics of new anthraquinone derivative-decolorizing versatile peroxidase produced by Bjerkandera adusta strain CCBAS 930

Abstract

The aim of the study was to purify and characterize a peroxidase synthesized by the B. adusta strain CCBAS 930. Moreover, optimal pH and temperature, substrate specificity (2,2′-azino-bis(3-ethylben-zothiazoline-6-sulfonate (ABTS), veratryl alcohol (VA), guaiacol (GA), o-dianisidine, 2,6-dimetoxyphenol (2,6-DMP), 2-methoxy-1,4-benzohydroquinone (MBQH2), 2,6-Dimethoxy-1,4-benzohydroquinone (DBQH2)) and the influence of different ions (Al3+, Mn2+, Mg2+, Ca2+, Cu2+, Fe2+, Co2+, Ag2+, Cd2+, Hg2+, and K+ and organic solvents (ethanol, methanol, DMSO, ethyl acetate, n-hexane, diethyl ether, and dichloromethane) on VP/Ba activity were determined. The purified VP/Ba had an RZ value (A407/A280) of 1.85, 45 kDa and an N-terminal sequence VTXPGKVNVVENSA. The catalytic activity of VP/Ba measured by the oxidation of 2,6-DMP with/without Mn2+ was noted at optimum temperature values of 50 °C and 55 °C, respectively. After 24h incubation in different pH conditions (pH = 3.0–7.0), residual VP/Ba activity ranging from 30 to 50% with the optimum at pH = 5.5 (50%) was observed. All the seven substrates tested were oxidized by purified VP/Ba, but the oxidation ratio of 2,6-DMP, VA, GA, and o-dianisidine in the presence of Mn2+ was higher. The highest activity of VP/Ba was detected in the presence of 0.1 mM Al3+, Cu2+, Ca2+, and Mn2+ ions (126%–176%), while Ag2+, Hg2+, Ni+, and K+ at all the concentrations tested (5, 1, and 0.1 mM) significantly decreased its activity. Organic solvents e.g. ethanol, methanol, DMSO, ethyl acetate, n-hexane, diethyl ether, and dichloromethane, partially decreased the activities of VP/Ba measured without and with Mn2+, with residual activities ranging from 10.33% to 69.16% and from 50% to 68.75%, respectively.