Light-emitting diode enhances the biomass yield and antioxidant activity of Philippine wild mushroom Lentinus swartzii

Lentinus swartzii is a basidiomycetous fungus that usually grows on fallen logs during rainy season. In this study, the effects of color light-emitting diode (LED) on the mycelial biomass, fruiting body production, and antioxidant properties of L. swartzii were evaluated. The inoculated culture bottles and fruiting bags were incubated under the three-color LEDs (red, green, and blue), and dark condition (control) in a chamber. Phenolic content and scavenging activity mycelia and fruiting bodies ethanol extracts were also analyzed. In liquid culture, red LED cultures produced the highest mycelial dry weight (0.464 g), while green LED cultures registered the highest number of primordia (6.0). The initiation of primordia was not stimulated under red LED and dark condition. However, in fruiting body production, fruiting bags exposed under red LED showed the shortest period of incubation for mycelial ramification (21.20 days), produced the maximum yield of fruiting body (35.73 g) and biological efficiency (7.14%). All LED mycelial extracts exhibited higher radical scavenging activities (RSA) than catechin, and green LED mycelial extract registered the highest phenolic content (PC) (34.21 mg GAE g-1 sample). The red LED fruiting body extract recorded the highest RSA (28.06%) and PC (26.08 mg GAE g-1 sample). Therefore, cultivation of L. swartzii in red LED chamber is a practical technique for enhancing biomass production and antioxidant properties.