Efeito do inóculo sobre a expressão de lacase por Lentinus crinitus CCIBt2611.

Abstract

The basidiomycete fungus Lentinus crinitus (L. crinitus), abundantly found in Brazil, is recognized for its ability to degrade cellulose, hemicellulose, and lignin, classifying it as a white-rot fungus. However, laboratory experiments have revealed that cultures stored for extended periods, such as those used in this study, tend to diminish the production of ligninolytic enzymes. In this context, the study aimed to assess whether the addition of toxic and recalcitrant compounds during inoculum production could stimulate the expression of laccase, a ligninolytic enzyme. Using the fungal isolate L. crinitus CCIBt 2611, which was maintained through successive subcultures in potato, dextrose and agar (PDA) medium, the inoculum was produced in PDA medium, as well as in PDA medium supplemented with wastewater from soluble coffee production (WSCP) and hydrothermal liquefaction of algae (HLA). Ten mycelial growth discs (7mm in diameter) were inoculated into Kirk liquid medium, incubated stationary and agitated (100 rpm) for 16 days. Every three days, samples (5mL) were taken for laccase activity determination, using ABTS oxidation, along with pH measurement. In the PDA, ARCS-supplemented PDA, and HLA-supplemented PDA inocula, a peak of laccase production was observed at day 9, with values of 18.53 U/L, 18.39 U/L, and 31.91 U/L, respectively, in stationary cultivation. Crude enzymatic extracts exhibited optimal pH and temperature of 3.0 and 60 °C, respectively. The results indicated that the use of toxic wastewater, HLA, as an inoculum, activated the expression of laccase in L. crinitus CCIBt 2611, displaying similar characteristics.