Abstract: This study aimed to investigate the effect of different concentrations of stalk-derived quality modification factor (QMF) solution on the biomass of Pleurotus ostreatus mycelia over a 7-day culture period and the effects of 0.5% QMF solution on dynamic changes in DPPH and hydroxyl radical scavenging capacity, total antioxidant activity (T-AOC) and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX). The results showed that the 0.5% QMF treatment led to an increase in the mycelial dry weight of Pleurotus ostreatus by 19.31% on the 7th day compared with the control group. Additionally, despite no marked change in the DPPH radical scavenging activity, there was an 8%—11% increase in the hydroxyl radical scavenging activity after cultivation for 5, 6, 7 days, and an increase in the total antioxidant capacity up to 32% on the fifth day was also found during the first 5 days of cultivation compared with the control group. Moreover, the activities of SOD, POD, CAT and APX after cultivation for 3, 4, 5 days showed increased levels compared with the control group (P ＜ 0.05). These observations show that treatment with 0.5% QMF solution can increase the mycelial biomass while apparently enhancing the antioxidant activity of Pleurotus ostreatus mycelia.

Key words: Pleurotus ostreatus, quality modification factor from stalk, liquid-state cultivation, antioxidation