| China is a large agricultural country with a great amount of straw resource whose annual straw output is 600～700 million tons. Each year a large number of straw is burnt because it can't be properly used which has Caused resource waste and environmental pollution. At the same time as large-scale use of chemical fertilizers, organic matter content gradually decreased in recent years and soil became hardened and impervious. Decomposition the waste straw quickly through the role of microbial agents to field soil will not only find a way for the giant amount of straw which piled everywhere in our villages but also is conducive to fertility increased and sustainable agricultural development, and will protect the environment at the meanwhile. Which meet the require of establishing a resource-saving and environment-friendly society.10 fungal strains and 2 strains of actinomycetes which can excrete cellulase efficiently were selected From the forest soil, farm soil, rotting straw and so on where cellulose decomposing bacteria surrounded by the method of plate-selection through determining the cellulase activity on congo-red plate. The strains were screened for sodium carboxymethyl cellulose enzyme(CMCase) and filter paper activity(FPA) of the enzyme assay. The highest cellulase producing strains were 51 which produced sodium carboxymethyl cellulose enzyme(CMCase) at 4.90U/mL and strain 104 whose filter paper activity is at 1.78U/mL.Strains antagonistic with each other were abandoned and then the rest were constructed by the orthogonal combination of strain compatibility. Then had the two activities of cellulase(CMCase and FPA) determined. The results show that only team 7 reflects the strain compatibility of co-strains enzyme production capacity while the remainders only reflects the combination of enzyme production capacity of the average strain, or low activity. A complex system which may decomposite straw efficiently formed by team 7 Obtained through a set of orthogonal co producing ability of the fungal cellulase composition with 2 strains of bacteria and four strains of yeast which stored in our laboratory formed. Select corn stalks and rice straws which are representative in China as experiment materials. Decomposite them with the complex system. After 30 days, the straw weight loss, size became much smaller, color became black with dark reddish brown liquid exudation. Through determination, the weight loss of corn stalks and rice straw reached 59%and 52%, significantly better than the commercially available agents(37%; 20%)and outstand the blank one(7%,6%). By morphological observation and microscopic examination, cellulase produced strains 51, R19, P11,104 and R18 were identified with results below:51 is Aspergillus strains, R19 is Penicillium, P11 is of Mold for the tooth stem twin genera,104 is Cephalosporium Corda, R18 is Mucor.Through single factor experiment, fermentation factors of team 7 which consists of five strains of fungi was studied and optimization of fermentation conditions was found in order to provide the basis for industrial production and follow-up experiments. The results showed that the best compatibility strain inoculation is 4mL, the most suitable culture temperature is 25℃, optimum growth pH is at 6.5, the best nitrogen source were complex nitrogen content of NH4Cl and yeast extract while the best carbon source is soluble starch, the best culture time is 4days. Optimized medium consist of soluble starch 10g, NH4CI 10g, KH2PO4 2g, MgSO4 0.5g, yeast extract 5g. Through the optimization of culture factors, the cellulose production activity of team 7 consisting of five strains of fungi rose from 6.01U/mL to 7.12U/mL, with a increase of 1.11U/mL, increased by 18.47% than the original.With Industrial and agricultural production and the use of cheaper agricultural waste as materials, solid fermentation agents was made by composite system according to national standards-"Agricultural Microbial Agents". Then the appearance of agents, effective viable microbe amount, cellulase activity, water rate, pH and so on were determined with the standards listed in "Agricultural Microbial Agents", the results showed that the agent looked brown and it is dry, loose with hand clenched while with a appearance of small granules. The effective number of microbe is 2.6×108/g which is about 5 times of the national standard(0.5×108/g), cellulase activity is 39.29U/g higher than the stated standard 30.00U/g, water content is 8.66% which is in the confine of the standard, pH of the agent is 6.78 which is between the national standard range(5.5 to 8.5). |
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