Studies On Mutagenesis Of Thermomonospora Fusca With (60) Co Gamma Rays And Its Application In The Fermentation Of Dung

In the intensive breeding of modern stockbreeding, the dung of livestock and fowl has led to more and more serious pollution of environment. It is a effective and good resolved way that dung is transformed the feedstuff by the fermentation. To achieve the destiny, the content of cellulose of the dung must be decreased, especially the dairy dung.The intention of this study is that a high cellulase-producing mutant strain was obtained by the mutagenesis of Thermomonospora fusca that can produce the heat-resistant and alkaline-resistant cellulase with Gamma Rays. Then, after the best conditions of growth and cellulase-producing of the mutant were mensurated and compared with those of the original strain, the best fermented conditions of it were achieved. At last, the mutant was used to ferment the dairy dung, and made the dung done the feedstuff. The research also studied the security of fermented dung as feedstuff.The main results and conclusions were as follows:1. The radiant dose of mutagenesis to the spore suspension was chosen 1. 2Kgy after the test of death rate was done by the grads-dose radiation to the original strain. A high cellulase-producing mutant strain AV5 was obtained by screening using the methods of transparent zone and shaking culture. After primary mensuration, the activity of producing cellulase of mutant strain AV5 was enhanced for 1.8 times comparing with that of the original strain at least. And the activity was steady.2. By a series of studies of biology and cellulase between the original strain and AV5, it is obvious that the maximal activity of the cellulase was 0.803IU/ml, which was 3.1 times higher than the activity of the original strain, and the heat-resistant activity of cellulase was strengthened. At the same time, the output of organism was increased. Then, the optimization conditions of fermentation was primarily described as below: 60°C in first 2 days and 55°C in residual, a initializing pH to 8. 0, and lasting for 7 days.3. After the AV5 and original strain were respectively inoculated in the sterilized dung of cattle, the dung was fermented through those best conditions illustrated as above. By the sterilized dung as comparison, the reducing rate of the CF of dung of inoculating AV5 was 32.95%, which is 1. 7 times higher than the reducing rate of the original strain.4. The acute and subacute toxicity experiments were done to the...