Artificial cultivation and nutritional evaluation of proteins from a wild Ganoderma gibbosum strain

Ganoderma gibbosum is a medicinal fungus widely distributed in China, but the scarcity of its wild resources has limited its application and potential economic value. In this research, we collected a macrofungus from the wild, isolated using tissue culture technique, and identified by morphological characteristic analysis combined with ITS sequencing and homology-based phylogenetic analysis. A DNA fragment of approximately 650 bp was obtained and the fungus was identified as G. gibbosum. Furthermore, the fungus was cultured in liquid medium and artificially cultivated for fruiting body development. The crude protein contents and amino acid compositions of the mycelia, artificially cultivated and wild fruiting bodies were systematically evaluated to assess the nutritional value. Protein quality was evaluated by calculating the amino acid score (AAS), chemical score (CS), score of ratio coefficient of amino acids (SRC) and essential amino acid index (EAAI), referring to the most recent version of the international amino acid reference patterns. The results revealed that 17 kinds of amino acids were detected, and the essential amino acid contents were superior to the WHO/FAO reference protein pattern value in the hydrolysates of samples. The most abundant essential amino acid in mycelia was Lys, whereas that in both artificially cultivated and wild fruiting bodies was Met. The SRC values were between 25.30 and 69.84, and the EAAI values were between 75.15 and 94.43, which basically conformed to the requirements of current international reference patterns. The study provides a scientific basis for further utilization of this fungus.