Objectives Lepista sordida (Schum.: Fr.) Sing. is a type of edible Agaricus mushroom. It exhibits several activities including immunomodulation, and antioxidant and anti-fungal properties. The objective of this investigation was to investigate the fermentation and extraction conditions of polysaccharides from the mycelium of L. sordida.
Methods This single parameter experiment was performed to identify the optimal culture conditions including culture temperature, culture cycle and initial pH. Furthermore, an orthogonal experimental design L9 (34) was used to evaluate the combination effects of carbon sources, nitrogen and minerals on the extracts from mycelia. Extraction conditions optimization including the ratio of water to material (v/w), temperature and extraction time based on response surface methodology was employed to identify the optimum conditions.
Results The maximum mycelium dry weight was obtained when cultured in an optimal composition of sucrose 30 g/L, yeast extract 6 g/L, KH2PO4 0.1 g/L and MgSO4 1 g/L at temperature 28° C, culture cycles of 7 days and initial pH 7.0. The optimum conditions for polysaccharide extraction from L. sordida mycelia were a ratio of water to material of 72.1:1, temperature 92.6° C and time 2.9 hours. Under these conditions, the predictive and practical extraction efficiency was 16.5% and 16.5±0.1%, respectively.
Conclusions The results are helpful for building an efficient and controllable model to improve the extraction efficiency for industrial production of bioactive polysaccharides from L. sordida.
Acknowledgments This study as supported by the Guangdong Provincial College Students Innovation and Entrepreneurship Training Program (Nos. DC2016062 and DC2016063).