Evaluation of Favorable Conditions to Improve Biomass Production and Antioxidant Activity by the Egyptian Ganoderma resinaceum EGM and G. mbrekobenum EGDA (Agaricomycetes)

Physiological studies were performed to investigate the optimal mycelial growth parameters for Ganoderma resinaceum EGM (AC: LN774970) and G. mbrekobenum EGDA (previously identified as Ganoderma sp. EGDA, AC: LN774971). The study found that the highest growth of mycelia was at 11 d for Ganoderma species. The nutritional studies were carried out to know the best growth conditions including temperature, culture media, pH, carbon source, and nitrogen source. The most appropriate temperature for the highest growth for Ganoderma species was at 30°C; this benefit enables the cultivation of these species in the spring. The most favorable media for their growth was potato dextrose broth as semi-synthetic followed by Saburaoud broth as synthetic media. They also could grow at pH ranges from 3.0-9.0, with the highest mycelial growth at pH 5.0. This study confirmed that both Ganoderma species prefer glucose as a carbon source and peptone as an organic nitrogen source. Decolorization of poly R associated with peptone was 21.37% and 18.66% for both EGM and EGDA strains, respectively. The highest cellulase production was achieved after 11 d of incubation with activity reached 0.305 μmole/mL/min and 0.236 μmole/mL/min for G. mbrekobenum EGDA and G. resinaceum EGM, respectively. The highest laccase activity was obtained after 8, 12 d of incubation with a value of 5.53 μmole/mL/min and 31.32 μmole/mL/min, for EGM and EGDA strains, respectively. Moreover, the highest peroxidase activity for both EGM and EGDA strains was recorded after 26 and 20 d of incubation with a value of 0.333 μmole/mL/min and 0.230 μmole/mL/min, respectively. G. mbrekobenum EGDA possessed higher flavonoids and phenolic compounds (4.098 mg/g and 6.298 mg/g dry weight, respectively) than G. resinaceum EGM (1.137 mg/g and 2.420 mg/g dry weight, respectively).