Estudo comparativo do cultivo de Ganoderma spp. em resíduos lignocelulósicos amazônicos visando a obtenção de inibidores de protease

Abstract

The cultivation of macrofungi has a long tradition in Asian countries. Among the cultivated species, those belonging to the Ganoderma genus stand out due to their medicinal properties. However, this genus still presents taxonomic classification ambiguities, and the content of active substances in these fungi is often variable depending on the cultivation conditions, substrate type, and lineage. The objective of this study was to compare a strain of Ganoderma isolated in the Amazon and a commercial strain regarding molecular characteristics, productive aspects, transformation of lignocellulosic residues, nutritional composition of basidiomata, and the synthesis of bioactive molecules. The fungi Ganoderma lingzhi (commercial strain) and Ganoderma sp. (isolated in the Amazon region) were initially molecularly identified. After species confirmation, they were cultivated in residues from acai seeds and sawdust from guaruba-cedro and marupa (marupa I, marupa II, and marupa III). The residues underwent physical-chemical and structural characterization analyses before and after the fungi cultivation. Biological efficiency (BE), yield, and loss of organic matter (LOM) were evaluated as productive parameters. The produced basidiomata were subjected to proximate composition analysis, different protein extractions, detection of protease inhibitors' activity, fibrinolytic activity, FTIR-ATR, and terpene analysis. Following the fungi's growth, a significant reduction in moisture, ash, nitrogen, and total protein levels in the cultivation substrates was observed. Structurally, the fungi caused a disorganization of the microfibrillar arrangement of the lignocellulosic residues. Regarding productive parameters, G. lingzhi and Ganoderma sp. showed higher BE and LOM when cultivated in marupa I and II-based substrates. Guaruba-cedro provided higher yields, particularly for G. lingzhi (3.81%). In terms of nutritional composition of the basidiomata, G. lingzhi presented higher levels of total carbohydrates (average value of 72%) and energy value (average of 388.1 ± 0.58 kcal/100 g) compared to Ganoderma sp., with an average of 53% of total carbohydrates and 242 ± 1.6 kcal/100 g. Conversely, Ganoderma sp. exhibited higher levels of proteins (36%) and total fibers (average of 48%). For protein activities, the extraction in Tris-HCl provided higher protein and protease levels for Ganoderma sp., while G. linzhi cultivated in acai displayed higher fibrinolytic activity (132.67 mm2). Aqueous extracts of Ganoderma sp. in marupa III and marupa II exhibited higher inhibitory activities against trypsin (390.09 UI/mg protein) and papain (255.67 UI/mg protein), respectively. G. lingzhi cultivated in guaruba-cedro showed higher chymotrypsin inhibition. The FTIR spectra confirmed variations in the chemical profile according to the substrate and the extractor, yet all exhibited protein fingerprints. Comparing the commercial strain with the Amazonian isolate of Ganoderma sp., the latter showed significant potential in obtaining proteolytic inhibitors.