Enzimas celulolíticas de macro-basidiomicetos isolados do cerrado tocantinense cultivados em biomassas lignocelulósicas residuais da agroindústria do açaí (euterpe spp.)

Abstract

The aim of this work were to isolate and evaluate macro-basidiomyc ete fungi, from the cerrado in Tocantins, with the capacity of growth in biomass of açaí byproduct and enzymatic production. The macro-basidiomycetes were grown in solid medium enriched wi th acaí berry (FC) fiber lignocellulosic substrates, or açaí seed fiber (FS) or potato broth, supplemented or not with glucose. The fungi were evaluated for mycelial growth diam eter, mycelial growth rate index and mycelial growth rate. The enzymatic production was performed using FC and FS as substrates, by submerged and solid culture. Solid-state cultivation (SSC) were made with five different formulations of the substrates. Co-cultivation betw een the macro- basidiomycetes and Trichoderma asperellum BC-2 A70882D isolates were performed in Petri dishes containing the PDA or MEA media. Among the eight macro-basidi omycete isolates, FPB 173 was selected for cultivation in submerged medium in monoculture and cocultivated with T. Asperellum BC-2 A70882D, for evaluation of the enzymatic activities of β - glucosidase, xylanases and lipases. Plate cultures containing BDA-C, FC-C and FC-S medium showed a significant difference in the mycelial growth diameter for the FPB 166 isolate, and the FPB 166 and FPB 173 had better mycelial growth index. In solid state cultures, the best formulation observed for all enzymes was F1. The FPB 167 line presented higher activity for β-glucosidase, and for CMCase, with 0.187 Ugss -1, 0.245 U.gss -1, respectively. The best observed activities for pectinase were FPB 166 (0.664 U.gss -1) and FPB 173 (0.615 U.gss -1), and for xylanase, FPB 169 (0.766 U.gss -1). In the submerged culture, the co-culture of FPB 173 and T. asperellum had the highest β -glucosidase activity in the substrates FC and FS, with 0.384 U.mL-1 and 0.366 U.mL -1 , respectively. For lipase, differences between the monoculture of T . asperellum and the cocultivation of FBP 173 and T. asperellum (0.747 U.mL-1 and 0.632 U.mL -1, respectively) were observed. In the results of the enzymatic activity of xylanase, monoculture of T. asperellum in FC, after 48 and 168 hours, reached 1,824 U.mL-1 and 1,732 U.mL -1, respectively. The biomass of the açaí agroindustry, when used as a carbon source or as a medium enrichment factor, for macro-ba sidiomycetes or cocultures in cultivation processes, were significant for mycelial growth and production of enzymatic complexes.