Solid-state fermentation of cornmeal with the ascomycete Morchella esculenta for degrading starch and upgrading nutritional value

摘要

The ability of the ascomycete Morchella esculenta to degrade starch and upgrade nutritional value of cornmeal during solid-state fermentation (SSF) was studied. On the basal medium, a-amylase activity of M. esculenta reached its maximum value of 215 U g(-1) of culture on day 20 after inoculation. Supplementation of glucose, yeast extract to the basal medium caused a significant increase in either the degradation rate of starch or the mycelial biomass as compared with control (P < 0.01). Through orthogonal experiments, the theoretical optimum culture medium for SSF of this fungus was the following: 100 g cornmeal, ground to 30-mesh powder, moistened with 67 ml of nutrient salt solution supplemented with 3 g yeast extract and 10 g glucose per liter. Under the optimum culture condition, the degradation rate of starch reached its maximum values of 74.8%; the starch content of the fermented product decreased from 64.5 to 23.5%.