Effect of different compounds on the induction of laccase production by Agaricus blazei

Laccases are polyphenol oxidases produced by many fungi and have many applications in textile, food and beverage, and pulp and paper industries. Laccase production can be induced using aromatic or phenolic compounds that mostly affect the transcription of laccase-encoding genes. In this study, we analyzed laccase and biomass production by Agaricus blazei in the presence of different concentrations of nitrogen, copper, and inducers such as pyrogallol, veratryl alcohol, xylidine, vanillin, guaiacol, and ethanol. Laccase production by A. blazei U2-4 reached 43.8 U/mL in the presence of 2.8 g/L nitrogen and 150 μM copper. However, addition of copper to the cultivation medium decreased biomass production. Different compounds differentially induced laccase production by A. blazei. Moreover, different concentrations of these inducers exerted different effects on laccase activity. Ethanol (1.0 mM), guaiacol (0.5 mM), and vanillin (0.5 mM) were the best inducers and increased laccase activity by 120% (A. blazei U2-2), 30% (A. blazei U2-3), and 9% (A. blazei U2-4), respectively. In contrast, pyrogallol and xylidine decreased laccase activity but increased biomass production.