Abstract:

Objective: To screen a Morchellas spp. strain having gastricprotective effect and higher biomass from 9 strains, and to optimize carbon and nitrogen sources for cultivation of the screened Morchellas spp. strain. Methods: Mice were randomly divided into normal group, control group and different dose administration groups. An experimental gastric damage model was established by ethanol intragastric infusion. On the basis of selection of the optimum carbon and nitrogen sources, their optimum amounts were optimized by complete combination experiments involving three levels for achieving an optimum compromise among low lesion index and high biomass and extracellular polysaccharide production. Results: The water extract of strain M1 could significantly reduce the injury index of acute gastric mucosa lesion in ethanol-induced mice and the amount of biomass was up to 10.28 g/L. In addition, the extract exhibited the best gastricprotective effect and provided inhibition rates up to 80.92% and 53.02% against gastric mucosa damage when the carbon and nitrogen sources were soluble starch and yeast extract during liquidstate fermentation. Better gastricprotective effect and higher biomass production could simultaneously be achieved by using 2.0% soluble starch as carbon source and 1.5% yeast extract as nitrogen source. As a result, the inhibition rate against grastric mucosa lesion was 76.02% and the biomass was 8.88 g/L. Conclusion: Strain M1 has the potential to protect against gastric mucosa lesion, and higher biomass during liquid-state fermentation can be achieved by using 2.0% soluble starch as carbon source and 1.5% yeast extract as nitrogen source.

Key words: Morchella escutenta, ethanol, gastric mucosa lesion, liquid-state fermentation