Abstract: The anti-Saccharomyces cereviviae effect and notable medicinal value of Lycoris radiata alkaloids highlight the importance and necessity of total alkaloids extraction before ethanol fermentation from L. radiata bulbs. In the present study, one-factor-at-at-time experiments were conducted to explore the extraction efficiency of total alkaloids from L. radiata bulbs with respect to five operating parameters including extraction solvent type, temperature, extraction time, solid-to-liquid ratio and pH. The results showed that the extraction efficiency of total alkaloids was up to 28.70 mg/g under the following conditions: methanol as extraction solvent, solid-to-liquid ratio of 1:15 (g/mL), temperature of 60 ℃, pH 11.0 and extraction time of 1 h. Further, the fermentation performance of L. radiata bulbs for producing ethanol was compared before and after the removal of total alkaloids. As a result, the presence of total alkaloids had dramatic inhibitory effect on glucoamylase activity and the growth of S. cereviviae and little effect on α-amylase activity. This can preliminarily explain the inhibitory mechanism of Lycoris radiata alkaloids on ethanol fermentation.

Key words: Lycoris radiata, alkaloids extraction, ethanol fermentation, inhibitory mechanism