Effects Of Carbon And Nitrogen Nutrient On Growth Development And The Extracellular Enzyme Activity In Pleurotus Geesteranus

Most edible fungi fell into saprophytic fungus whose growth required nourishment absorbed from the external world. Carbon and nitrogen were two major nutrient elements. During the cultivation of Pleurotus geesteranus, the choice of carbon and nitrogen sources,suitable C/N and N% played an important role in mycelial growth and fruitbody growth with high yield and high quality. In this experiment, Pleurotus geesteranus was used as testing material. The utilization of carbon sources, nitrogen sources, C/N and N% and the law of extracellular CMCase, HCase, Laccase, Guaiaualoxidase, produced by mycelia were studied. The results laid a foundation for further research on nutrient physiologic of Pleurotus geesteranus. Meanwhile the outcomes provided an important reference for selecting excellent medium.1. At the stage of cultivating maternal strains, the utilization of Pleurotus geesteranus with five different carbon sources from D-fructose, Glucose, Maltose, Soluble starch, Sucrose, Lactose and six kinds of nitrogen sources from Yeast extract, Peptone, NH₄Cl, (NH₄)₂SO₄, KNO₃, NH₄NO₃, Urea in completely synthetical medium were studied. The producing law of extracellular enzymes in carbon and nitrogen sources mediums were also studied. The results showed that the optimum carbon source was Maltose and the optimum nitrogen source was Yeast extract and Peptone. During the mycelium growth, extracellular enzyme activity of CMCase, HCase, Laccase, Guaiaualoxidase, had something to do with certain kinds of carbon sources or nitrogen sources, but had no relationship with mycelial growth rate. When C-source was Maltose or D-fructose, N-source was Yeast extract and Peptone, it was beneficial to the production of CMCase and HCase. As to Laccase, the optimum C-source were Maltose and Soluble starch, the optimum N-source was Yeast extract, Peptone and (NH₄)₂SO₄. When C-source were Maltose and Soluble starch, N-source was Yeast extract and Pepotone, it was beneficial to the production of Guaiaual oxidase.2. When maternal strains were cultivated, as far as Pleurotus geesteranus was concerned. There were 25 treatment group were designed when C/N was from 10: 1 to 50:1 and N% was from 0.1% to 0.7%. The results were indicated, the optimal C/N was among10:1 and 30:1; more suitable N% was among 0.4% and 0.55%. Four kinds of extracellular enzyme need different C/N and N% during mycelium growth period. Extracellular CMCase were higher when N% was 4% and C/N was among 20:1 and 30:1. When N% was 4% and C/N was 30:1, N% was 7% and C/N was 30:1 or N was 7% and C/N was 50:1, these treatment groups were beneficial to the production of HCase. As to Laccase, the optimum treatment groups were that N% were among 5.5% and 7%, but the variation of C/N did not play the important role in the production of Laccase. when N% was 7% and C/N was among 20:1 and 40:1, the treatment groups were beneficial to the production of Guaiaual oxidase.3. Using cotton seed hull, wood-sawdust and wheat bran as to major components of cultivation medium, there were 12 cultivation medium treatments were designed. The results indicated that the optimal C/N for Pleurotus geesteranus was 39.21:1～51.32:1 and N% was 0.82%～1.06%.4. The effects of C/N and N% of cultivation medium on four kinds of extracellular enzyme activity were great, but the effect on changing law of enzyme activity was small. The change of enzyme activity was related to fruitbody development. At the stage of trophic growth, the extracellular Laccase and Guaiaual oxidase were higher. At fruitbody development stage, these two kinds of enzyme activities decreased. The two kinds of extraeellular enzyme activities showed a tendency to increase after fruitbodies were harvested. At the stage of trophic growth, the extracellular CMCase, HCase activities were lower. The enzyme activity began to increase when it entered the stage of reproductive growth..The activity peak appeared coincidentally with the mature period of the fruitbody. After fruitbodies were harvested, these two kinds of extraeellular enzyme activities showed a tendency to decline.5. After measuring days of primordium formation and biological efficiency of culture medium with different C/N and different N% treatments, the conclusions of correlation testing showed that there was no significant correlation between biological efficiency and days ofprimordium formation.