The Influence Of Cultivature PH On The Enzyme Activities Of The Krebs Cycle In Suillus Luteus

Suillus luteus (L.:Fr.) Gray is a kind of exogenous mycorrhizal fungi with high nutritional and medical value.The optimum growth pH of the bacteria is relatively low. If it grows in the medium higher than the optimal pH condition, it will regulate the pH of the environment by secreting acidic substances. The activity of 8 kinds of enzymes of the Krebs cycle in the different cultural pH conditions was studied to understand how the environment pH influences its growth and metabolic.The results showed that, the effect of pH of the cultural medium on the enzyme activity is greate.In the liquid culture conditions,the pH in that cultural condition the fungi get the highest enzyme activities in per unit mass of fresh mycelium of CS, ACO, IDH, a-KGDH, SCS, SDH, FUM, MDH are about 5.0,6.0,6.0,6.0,5.5,5.5,5.5,5.5. The enzyme activities are 37.512,27.93,30.456,40.392,0.489,0.317,0.024 and 0.211 U/gfresh mycelium. The patterns of activities of those enzyme varing with pH of the cultural medium are like two curves.All the pH of the highest enzyme activity of the 8 kinds of enzymes in per gram protein is 2.5. The enzyme specific activities are 6.372,68.504,1.25,3.95,81.29,68.503,4.66 and 43.28U/mg protein. In the different pH liquid environment, the enzyme activities of the fresh mycelium in the Krebs cycle were highest in the range of pH5.0 to 6.0. The enzyme specific activities were the highest in the condition of low pH.