The effect of various inducers and their combinations with copper on laccase production of Trametes versicolor pellets in a repeated-batch process

The aim of this study was to increase laccase production in Trametes versicolor ATCC 200801 pellets by using various inducers and their combinations under repeated-batch conditions. Because copper is an effective inducer for laccase production, the effect of Cu on laccase production in this strain was tested first. The optimal Cu concentration for the highest laccase production was 0.5 mM. Following this preliminary study, the effect of other inducers [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), syringaldazine, guaiacol, and 2,5-xylidine] on laccase production was determined. Copper was determined to be the most efficient inducer among the inducers used. Therefore, the synergistic effect of each inducer with Cu on laccase production in this strain was investigated. While the maximum laccase activity was 0.60 U/mL in stock basal medium (SBM) alone, the highest enzyme activities detected were 4.76 and 2.87 U/mL in SBM + 0.05 mM ABTS and SBM + 1 mM 2,5-xylidine, respectively. Maximum laccase activities obtained from the combination of the inducers were 33.61 and 26.49 U/mL in SBM + 0.5 mM Cu + 0.5 mM 2,5-xylidine and SBM + 0.5 mM Cu + 0.05 mM ABTS, respectively. These were the most efficient combinations for laccase production.