The activity increased proportionally to ABTS concentration, and became saturated at above 2 mM, showing maximum activities of 1,560 units/L and 600 units/L for Lacc6 and Lacc12, respectively, and Km values of 0.152 mM and 0.316 mM for Lacc6 and Lacc12, respectively (Fig. 5A). Vmax/Km, which represents the enzyme catalytic activity at low substrate concentration, was 10,263 units/L/mM and 1,898 units/L/mM for Lacc6 and Lacc12, respectively. These findings indicate that Lacc6 is 5.4-fold more active than Lacc12 at low substrate concentration. Both enzymes were highly active at acidic pH. Notably, Lacc6 showed lower pH optimum than Lacc12 with optimum pH values of < 3.0 and 3.5 for Lacc6 and Lacc12, respectively (Fig. 5B). The effects of temperature on laccase activity were also slightly different. Specifically, Lacc12 showed a 5oC higher temperature optimum than Lacc6; however, both enzymes were essentially thermophilic, with optimum temperatures of 45oC and 50oC for Lacc6 and Lacc12, respectively (Fig. 5C).