Palanivel Sathishkumar - Laboratory of Bioprocess and Engineering, Department of Biochemistry, Periyar University, Salem – ۶۳۶ ۰۱۱, Tamil Nadu, India.
Thayumanavan Palvannan - Laboratory of Bioprocess and Engineering, Department of Biochemistry, Periyar University, Salem – ۶۳۶ ۰۱۱, Tamil Nadu, India.Corresponding author

Pleurotus florida produces two extracellular laccase (L1 and L2) isoenzymes and the L1 isoenzyme is dominantly involved in the dye decoloration process. L isoenzyme was successfully purified to 6.4 fold with a yield of 36% and had a specific activity of 52.6 U mg^-1 of protein. The purified laccase was monomeric with an apparent molecular mass of ≈54 kDa. The optimum pH and temperature of the LI isoenzyme was found to be around 5.5 and 50ºC, respectively. L1 isoenzyme showed a half life of 2 h at 60 ºC and at 4 h it retained around 25% residual activity. The kinetic parameters suggest that the order of affinity towards the tested substrates was syringaldazine > ABTS > DMP > guaiacol. Interestingly, L1 isoenzyme was not significantly inhibited by chloroform and benzene, whereas above 50% of laccase activity was inhibited by acetone, dimethyl sulfoxide and methanol.

Decoloration, Isoenzyme, Laccase, Pleurotus florida, Purification, White-rot fungi