Effect of inducers and culturing processes on laccase synthesis in Phanerochaete chrysosporium NCIM 1197 and the constitutive expression of laccase isozymes

Phanerochaete chrysosporium NCIM 1197 constitutively secretes considerable level of extracellular enzyme laccase in defined growth medium. Effect of several inducers on laccase production was attempted and found that copper sulphate alone at 30 mM concentration accelerate the laccase production at 3.5-fold increase compared to control. Solid-state fermentation using wheat bran as substrate exhibit, maximum laccase activity of 48.89 ± 1.82 U/L on day 5, whereas it was only 30.21 ± 1.66 and 22.56 ± 1.22 U/L, respectively, in batch fermentation in a laboratory scale bioreactor and in static liquid culture on the same day. The molecular weight of partially purified laccase was found to be 62 kDa. The presence of isoforms as evidenced through Native PAGE reveals that, supplementation of inducers only accelerates the laccase production and are not at all involved in the isoform expressions.