Improvement in the effectiveness of Cryptococcus laurentii to control postharvest blue mold of pear by its culture in β-glucan amended nutrient broth

• Efficacy of C. laurentii vs. P. expansum increased with NYDB amended with β-glucan.
• C. laurentii growth increased after cultivating in NYDB amended with β-glucan.
• β-glucan stimulated the ability of C. laurentii to secrete β-(1-3)-glucanase.
• β-glucan stimulated the activities of SOD and CAT of C. laurentii.

The addition of β-glucan at 5 g L−1 to nutrient dextrose broth during the culture of Cryptococcus laurentti improved its activity subsequently to control postharvest blue mold, caused by Penicillium expansum, on pear fruit. It enhanced the colonization of the fruit by C. laurentii, increased β-(1,3)-glucanase activity in a cell-free filtrate of the culture medium, and, in C. laurentii, it increased activities of superoxide dismutase (SOD) and catalase (CAT) and decreased the malondialdehyde (MDA) content. The increase in active oxygen metabolism indicates that it may be related to the increase in biocontrol efficacy of this yeast. The use of β-glucan in the culture of this yeast was an effective method to enhance the antagonistic activity of C. laurentii.