Produção de basidiomas e enzimas ligninolíticas de Ganoderma lucidum em resíduos de licuri

Abstract

Ganoderma lucidum (Curtis) P. Karst is a medicinal fungus (Basidiomycota, Polyporaceae) popularly known as "Lingzhi" in China, "Reishi" in Japan and "Mushroom King" in Brazil, which has been cultivated in several lignocellulosic materials. In the present study, the formation of mycelium as well as the production of ligninolytic enzymes and basidiomata of this species were evaluated in waste fruit shell, leaf and bract endemic palm of the Brazilian semi-arid region, Syagrus coronata (Martius) Beccari (licuri) by solid state fermentation. The optimal cultivation conditions were the same for all three types of substrates tested (pH 6.5, C/N ratio of 40 and 30°C of temperature) and were established from assays in Petri dishes and contour graphic analysis and response surface methodology. The enzymatic activity of laccase and manganese peroxidase were determined using spectrophotometric methods at intervals of 7 days by cultivating the strain in the three substrates selected for 28 days of incubation. The activity of the laccase was determined at 420 nm, using ABTS: 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) as the enzymatic substrate, and the activity of the manganese peroxidase at 610 nm by oxidation of phenol red. The highest peak activity for laccase (13,80 U/L) was found in bract substrate in 14 days of incubation and did not differ significantly from the others at 95% of statistical confidence. That substrate also resulted in the highest peak of activity for manganese peroxidase (14,92 U/L), which only occurred after 28 days of incubation, differing from the previous one at 5% probability. The assay for the production of basidiomata was performed in polypropylene bags. The only substrate that did not promote the formation of the basidiomata was the fruit shell. The biological yield did not differ significantly at 95% confidence in the bract (33,53 g/kg) and leaf (37,48 g/kg) substrates. The biological efficiency also was not statistically different in the bract (3,35%) and leaf (3,75%) substrates. Thus, it is believed that the licuri wastes are potential substrates and can be used in the bioconversion processes for the formation of the mycelium and basidiomata as well for ligninolytic enzymes production in G. lucidum.