The Enzyme-Producing Conditions Of Cellulose-Decomposing Thermoactinomyces Strain And Polymorphic Taxanomy

Thirty-three thermoactinomyces strains were isolated from the straw compost collected from Jianyang, Dujiangyang, Wenjiang, Dayi, Jiajiang, Pengzhou, Emei, Yaan, Mingshan in Sichuan province, and the University farm of Sichuan Agricultural University. A good cellulose-decompsing strain, named CN9, was screened. The CMCase producing condition was studied. At the same time, the polymorphic taxonomy of strains CN9 and DY19 were performed. The results were:1. By the method of the size of clear zones on the cellulose Congo red medium, 5 strains having good cellulose-decompsing ability were screened from the 33 thermoactimomyces. Then, by the method of filter paper weightlessness, the strain CN9 with the best cellulose-decompsing effect was selected.2. The result of liquid fermentation of CN9 showed that its filter paper enzyme activity was 0.096U/g, the enzyme activity C₁ was 0.062U/g, and Cx activity was3.866 U/g, respectively; the result of solid fermentation of CN9 showed that the filter paper enzyme activity was 3.25U/g, C₁ activity was 0.06U/g, and the C_x activity was 14.6 U/g. The CMCase producing condition of strain CN9 was explored, the results showed that the best culture materia were bran as carbon source, soybean meal as nitrogen source; Meanwhile, Ca²⁺ could advance the cellulase activity of CN9. The optimum culture condition was: incubating at 45℃, shaking at 250r/min, and culturing for 120 hours. Bran, soybean meal, Ca²⁺ and culturing-temperature as four factors, the orthogonal experiment was used to choose the optimum medium. The results indicated that the optimum condition of producing CMCase was as follow: bran 10g/L, soybean meal 4g/L, Ca²⁺0.4g/L, and the optimum culture temperature was 45℃. And the CMCase activity was 11.52 U/g under this condition.3. The result of polymorphic taxanomy to CN9 indicated that: CN9 had abundant subsreate mycelium and spore chain. Growth on the eight different culture media, the color of aerial mycelium was white or yellow, but no soluble pigment was produced; the growth temperature of CN9 ranged 28℃to 65℃, and the optimum growth temperature was 55℃; the optimum pH value for CN9 was 7-10. It was interesting that CN9 could grow on the culture medium containing 3 % NaCl. Except for D-ribose, CN9 could not make use of the other carbon sources; however, it could use most of the tested nitrogen sources; the result of chemotaxonology indicated that cell wall of CN9 had L, L-DAP, which belonged to the cell wall aminophenol type I. and the cell saccharide type C; The phylogenetic analysis of the partial 16S rDNA sequence indicated that CN9 located to the thermocoprophilus branch, which suggested that CN9 belonged to thermocoprophilus sp..4. The result of polymorphic taxanomy to DY19 indicated that DY19 had acerose subsreate mycelium and had single spore on it; the aerial mycelium was helical or slightly helical. Growth on the eight different culture media, the color of aerial mycelium of DY9 was white or yellow; but the subsreate mycelium had different color, and most was primrose, and also there was no soluble pigment produced; DY19 could grow at 45℃, and the optimum temperature was 55℃; the optimum pH value for DY19 was 8-10. DY19 could not make use of most carbon sources but the D-ribose; and could use most of nitrogen sources; the result of chemotaxonology indicated that cell wall of DY19 had meso-DAP, which belonged to the cell wall aminophenol typeâ…¢and the cell saccharide type C; The phylogenetic analysis of partial 16S rDNA sequences of DY19 indicated that it belonged to Thermopolyspora of Streptosporangiaceae.