Study On Fermentation Biology Of Suillus Luteus (L.: Fr.) Gray

Liquid fermentation of mycorrhizal fungus Suillus luteus(L.: Fr.) Gray were studied in this paper. The mycelia obtained from BioFlo5000-120L fermentor was made into mycorrhizal inoculum and its storing temperature and active life were studied. At the same time, the infection capacity of different type inoculums association with Pinus tabulaeformis Carr. were tested and drought resistant and biochemistry reaction mechanism of mycorrhizal seedlings were probed.The main results were following:1. The superior strain Suillus luteus SP7 selected from 17 strains grew best in modified MMN medium. The inoculum type of flask was tested and the results showed that the fermenting period was shortened by 4d and the mycelial biomass enhanced by 16.11% with liquid fungi seed in contrast to agar solid seed.2. Carbon and nitrogen sources, media ingredients and fermenting technics of Suillus luteus SP7 were studied with single factor test and orthogonal test. The results showed that the optimal carbon and nitrogen sources were wort and yeast extract respectively. The optimal ingredients of the medium was made of wort 270mL/L, yeast extract 6.7g/L, KH₂PO₄ 0.25g/L, MgSO₄·7H₂O 0.3 g/L, CaCl₂ 0.19g/L, FeCl₃ 4.8mL/L, citric acid 0.1 g/L, VB₁50mL/L. The optimum shake flask technics was media capacities 50mL/500mL, seeding volumes 10%, initial pH value 5.5～6.5, seed ages 8～9d, rotation speeds 150 rpm～175rpm, cultural temperature 25℃. Anti-foam hasn't remarkable influence on the biomass. The fermentation type of Suillus luteus belongs to batch fermentation. Fermenting periods of shake flask was 9d. The maximum mycelia was 11.52g/L and 35.51% was enhanced by. Nutrition metabolization and the change of pH values were realized.3. Fermentor cultivation and kinetics of Suillus luteus were studied. The influence of dissolved oxygen, pH value and seeding volumes in 5L fermentor to mycelia were realized by 4 batch tests. Consequently the kinetics model of Suillus luteus was following: growth kinetics model: substrate consumption model: -In 120L fermentor, with best conditions design, the fermenting period was 204h and the mycela biomass could reach a new high level of 12.56g (dry weight) /L (media). The mycelia biomass was enhanced by 10.76% in contrast to 5L fermentor before best design and 71.49% was enhanced by before the initial biomass in shake flask and almost developed its all potential.4. The active life of solid inoculum, liquid inoculum and capsule inoculum in different temperature were studied. The results revealed that in 4℃conditions, the period of validity of solid inoculum and capsule inoculum was both 5 months and that of liquid inoculum stored in 4% glucose solution and 4% NaCl solution were 3.5 and 0.5 months respectively.5. The infection capacity of solid, liquid and capsule inoculum of Suillus luteus association with Pinus taebulaeformis seedlings was tested. The results revealed that 3 kinds of inoculum showed relative high infection rates to seedlings. Liquid inoculum was upmost for 71%, solid inoculum for 63% and capsule inoculum lowest for 60%.6. Several growth and drought resistant indexes of mycorrhizal and non-mycorrhizal seedlings were studied. The biomass, seedling height, ground diameter, root/shoot rate and the number of lateral roots of mycorrhizal seedlings were enhanced in different degree in contrast to the control. Drought resistant test seedlings showed that free water and bound water of mycorrhizal seedlings were enhanced by 7.56% and 60.39% respectively in contrast to the control. Water potential was enhanced by 13.33% and chlorophyll was increased by 17.14% on mycorrhizal seedlings. The SOD and POD viability of mycorrhizal seedlings were increased by 17.2% and 54.55% respectively. Pro. content was increased by 102.53% and MDA was lowered by 6.71%.Liquid culture of Suillus luteus was broken through and its optimal fermentive technic was obtained. The mycelium was made into inoculum by certain technics. The inoculum not only has long active life, but also remarkable effect of promoting growth of Pinus tabulaeformis. At the same time, the drought resistance capacity of mycorrhizal seedlings was strengthened. This proved favourable application foreground of Suillus luteus in forestation and vegetation restoration of Pinus tabulaeformis in arid and self-arid area sufficiently.