The fungal strain FBV40 was isolated from soil containing decayed wood in Ba Vi National Forest and capable of producing an extracellular laccase in the TSH1 medium. Two isozyme such as Lac1 and Lac2 were purified were estimated to be 55 and 60 kDa by SDSPAGE. The optimum pH and temperature for the enzymatic activity of Lac1 were and 60°C with ABTS using as the substrate. | Vietnam Journal of Science and Technology 55 (4C) (2017) 180-185 PURIFICATION AND CHARACTERIZATION OF LACCASE INVOLVED IN THE DECOLOURIZATION OF SYNTHETIC DYES AND 2,3,7,8-TCDD CONGENER DEGRADATION BY THE WHITE ROT FUNGUS ISOLATED FROM BAVI FOREST OF VIETNAM Phung Khac Huy Chu1, 2, Nguyen Hai Van3, Dang Thi Cam Ha3, * 1 2 The Chemical Command, the Ministry of Defence, No 1, Phan Van Truong, Ha Noi Graduate University of Science and Technology, VAST, 18 Hoang Quoc Viet, Ha Noi 3 Institue of Biotechnology, VAST, 18 Hoang Quoc Viet, Ha Noi * Email: phunghuychu@ Received: 30 June 2017; Accepted for publication: 17 October 2017 ABSTRACT The fungal strain FBV40 was isolated from soil containing decayed wood in Ba Vi National Forest and capable of producing an extracellular laccase in the TSH1 medium. Two isozyme such as Lac1 and Lac2 were purified were estimated to be 55 and 60 kDa by SDSPAGE. The optimum pH and temperature for the enzymatic activity of Lac1 were and 60°C with ABTS using as the substrate. Kinetic constants Km and Vmax of Lac 1 were µM and 200,000 µM/mins with ABTS as substrate. Cl-, SDS, and EDTA at any concentration (2 mM; 5 mM and 10 mM) strongly inhibited the activity of laccase. The enzyme was stable in the presence of several metal ions including Ni2+ (1 mM), Cu2+ (1 mM and 3 mM), Ca2+ (3 mM and 4 mM); in the presence of Cu2+ (2 mM) and Ca2+ ( mM, mM and mM), laccase even showed the increase in the activity. The presence of metal ions Mn2+, Mg2+, Fe2+ completely inhibited the enzymatic activity at any examined concentration. The crude enzyme, as well as Lac 1, was able to decolourization dye from the textile industry from Ministry of Defence. This strain was able to degrade 2,3,7,8-TCDD isotop with initial concentration 2,000 ng-TEQ/L at rates over % after ten days cultivation in the TSH1 medium. In the presence of three strains FBV40, FBVLa1 and FBD154 with the ratio 1:1:1, the degradation of this .
