| Suillus luteus is a superior ectomycorrhizal fungus, and has nutritional and medicinal value. Research has shown that there are two peaks about the mycelium biomass with the change of the initial pH after a period of cultivation time, and the decline of culture pH was larger when the initial pH higher than 5.5. In order to investigate the reasons for this phenomenon and further study the impact of the initial pH on the mycelium growth and medium acidification. The experiment make the mycelia grow in different pH condition of medium. Interaction between Suillus luteus mycelium and pH of culuture media was studied through investigation on the variation of biomass, the pH values of the substrates and so on. The result shows that, the type and amount of organic acids secreted by the mycelium is different in different initial pH. Oxalic acid can be produced in pH4.5~7.0, and acetic acid can be produced in pH5.0. The secretion of oxalate from unit of mycelium increases with the increase of initial pH. In the range of pH4.5 ~ 6.0 the concentration of oxalate ionized H+ accounted for the medium of the overall percentage increased in the concentration of H+ increases with increasing pH. When the pH is 7.0, the concentration of oxalate ionized H+ is the medium concentration of H+ increased 16 times. The mycelium of pre-culture at pH 6.0 conditions is good for secretion oxalate, and the acidification of the oxalate on culture is decreasing with the culture time long. There is significant correlation among the pH values of the substrates,consumption of sugar and the mycelium biomass. The rate of secretion of oxalate is slow in pH4.5~7.0 after 12 days. Potassium has inhibition influence on mycelium growth, and the rate of secretion of H+ is significantly lower with the increase of potassium concentration. The pH values of the substrates may affect the way of the mycelium metabolizing organic acids. The mycelium also secretes some particular substances to change the medium pH. |
PDF Full Text Request