Environmental Drivers of Ganoderma resinaceum and Ganoderma enigmaticum Mycelial Growth on Malted Sorghum and Associated Changes in Antioxidant Activity and Mineral Composition: Implications for Pito Bio-Enrichment.

Ganoderma species are increasingly recognized as promising sources of bioactive compounds for food and nutraceutical applications. This study evaluated the effects of temperature, light regime, and inoculum size on the mycelial growth of Ganoderma resinaceum and Ganoderma enigmaticum cultivated on malted sorghum, with implications for future pito bio-enrichment. A factorial design was used with temperatures of 25°C, 30°C, and 35°C, light conditions of complete darkness or a 12 h light/12 h dark cycle, and inoculum sizes of 2%, 4%, 6%, and 8%. Significant treatment effects on mycelial length were observed for both species at all incubation days (p < 0.001). Mycelial growth was fastest at 30°C in the dark with 6% to 8% inoculum; by day 6, GE308D and GR308D had attained the maximum mycelial length of 8.7 mm. GE308D (53.00% ± 0.10%) and GR308D (49.00% ± 0.10%) had the largest mycelial masses. GR308D showed the strongest antioxidant activity (EC50 6.7 ± 0.10 mg/mL), whereas GE302D showed the weakest (13.6 ± 0.11 mg/mL). Potassium was highest in GR254D (472.00 ± 17.00 mg/kg), phosphorus in GE308D (940.67 ± 21.50 mg/kg), magnesium in GR308D (4004.00 ± 92.00 mg/kg), calcium in GE308D (884.00 ± 16.00 mg/kg), and sulfur in GR308D (213.00 ± 15.00 mg/kg). These findings identify 30°C, darkness, and 6% to 8% inoculum as favorable conditions for biomass production, enhanced antioxidant activity and mineral enrichment.