Induced laccase secretion in Pycnoporus sanguineus and Trametes villosa with the addition of Cu as an inducer

VILLALBA LL, ZAPATA PD, SHIMIZU E, VÉLEZ RUEDA JO, MARTINA PF

Madision

Congreso; 10th International Congress on Biotechnology in the Pulp and Paper Industry.; 2007

ICBPPI

Abstract. White rot fungi secrete a wide range of extracellular enzymes involved in lignocellulosic substrates degradation. Laccase is one of the most important enzymes for biotechnology applications in the pulp and paper industry. Nevertheless, to develop industrial applications, it is essential to increase the enzyme secretion by adding inducers based on previous knowledge of gene promoter regions. Cu binding site promoters have been identified in various laccase genes. We analyzed biomass and enzyme production of two white rot fungi from the province of Misiones, Pycnoporus sanguineus and Trametes villosa, with and without the addition of SO4Cu, an enzymatic activity inducer. To determine the effect of the inducer, fungal cultures were grown on liquid medium supplemented with 0, 5 and 1 mM SO4Cu. Biomass weight was determined after filtering the mycelium from the liquid culture and oven drying. Measurements were taken at 5, 7, 10 and 14 days. Copper addition inhibited fungus growth but caused a significant increase in enzyme activity. Laccase activity in Trametes villosa was increased from 81 U/L (without Cu) to 979 U/L (0,5 mM Cu) at 14 days of cultivation, whilst in Pycnoporus sanguineus was increased from 237 U/L (without Cu) to 560 U/L (0,5 mM Cu) at 10 days of cultivation. Higher copper concentrations inhibited growth. Biomass reduction and enzyme secretion increase as a function of inducer addition are two beneficial coexisting factors for an industrial laccase application