Optimisation of medium and culture conditions for the production of antifungal substances toColletotrichum musaebyTrametes elegansSR06

An endophytic fungus SR06 was isolated from a leaf of Amomum villosum Lour., which had a high antagonistic effect on Colletotrichum musae with an inhibition ratio of 41.20%. The antifungal substances could be secreted into fermentation broth, which had a high inhibitory activity. Strain SR06 was identified as Trametes elegans according to internal transcribed spacer sequence analysis. Response surface methodology (RSM) was used to optimise the process parameters of antifungal substances production. Using the Plackett–Burman design, three variables (glucose, yeast extract and MgSO4·7H2O) exerted significant effects on antifungal substances production. Then RSM experiments were conducted to further optimise the three variables. The optimal medium components were 26.45 g/L glucose, 10 g/L peptone, 14.96 g/L yeast extract and 1.49 g/L MgSO4·7H2O, and the optimal initial pH was 6.0, with a culture temperature of 28°C and a shaking speed of 180 rpm. Under the optimised conditions, a significant improvement in the production of antifungal substances by T. elegans SR06 was accomplished, and the inhibition zone diameter was up to 29.2 mm after culturing for 7d. The average control efficacy of the fermentation supernatant of SR06 against C. musae was 51.29% on banana fruits, which was significantly higher than that of the fungicide carbendazim.