Study On Production Of Protein Feed From Corn Straw By Treatment Of Microorganism

High-yield cellulase bacteria were isolated from rumen. After the primary screening test by cellulose-congo red agar medium, the second one by flask cultivation and then solid fermentation, A Bacillus X4 was obtained. This strain not only was capable of degrading cellulose, but also possessed the ability to fix Nitrogen. The optimum PH of it was at 7.0, The suitable temperature for the growth of )Q was about 37癈. The strain X4 was able to symbiosis well with other selected strains in the co-fermentation. The yeast called Y2 was separated from rumen too. The experiments showed that yeast Y2 matched better with mixed strains. And it grew quickly with reducing sugar which was produced by other selected strains in the co-fermentation resulting in higher biomass.According to characteristics of the multi-microorganisms symbiosis and their metabolism, the corn straws were pretreated with the ammonia and white-rot fungi Lx, Trichoderma koningii Oud C413, high activity Aspergillus niger Sy, rumen bacterium X4 and rumen yeast Y2 were carefully selected and were inoculated on pretreated corn straws powder for multi-strains co-fermentation. The result of orthogonal experiment showed: with the fermentation temperature 30癈, PH 5.0, After 9 days, the contents of raw proteins reached 24.61% While the degradation ratio of cellulose was 48.37%.The suitable condition of protoplast formation and regeneration of yeast Y2 were studied. The result of experiment showed that: the early exponential phase cells (about 24h) were easy to form protoplast, under the action of 1.5% snail enzyme and 0.1% (3 -mercaptoethanol, the ratio of protoplast formation was about 95% in 60 minutes. On the conditionthat 0.6mol/l sucrose was used as osmotic stabilizer, the ratio of protoplast regeneration was the highest. The ratio of its regeneration was 6.32%.A mutagenic strain called Y2' was achieved using irradiating protoplasts by He-Ne laser ( A =632.8nm). Its biomass yield increased as much as 1.31 times than that of starting strain. And it match excellently with other mixed strains. The esterase(EST) isoenzyme electropheresis bands of the mutagenic strain Y2' compared with that of starting strain changed dramatically. The result of co-fermentation utilizing 2' indicated the content of crude protein in production reached 28.10% while at the same time the degradation rate of cellulose came to 51.12%.