Screening Of Antagonistic Actinomycetes Of Several Forest Pathogeny And Study On Bioactive Metabolite

512 strains of actinomycetes were separated from the soil collected in 10 samples forest litters in Huoditang Mts . Though elementary classified,292 strains were used for antagonistic experiment. Though test of ferment liquid bioactivity and biological test, N.O 268 strain was screened. Some studies were go along. The main results were as follows:1.GA,Asa,Aa and K2Cr2O7(150mg/L) were fit into isolation of actinomycetes in this kind soil samples.2.In every soil samples, streptomyces were dominant genus. In Streptomyces,Roseosporus and Aureus and Griseofuscus were dominant groups.3.The results of agar plate antagonism experiment showed that: 14 and 42 and 45 and 50 and 162 and 89 and 68 and 289 strains had better bioactivity to many forest pathogenies. By means of test of ferment liquid inhibition, 42 and 189 and 268 strains had better bioactivity to many forest pathogenies. The result of biological test showed that 268 strain had better prevent effect. The prevent effect was 64.7%.4.Extraction experiment of ferment liquid of N.O 268 strain showed that the Ethyl acetate fraction had best bioactivity. And TLC method was used. The result revealed that the bioactivity was caused by one weaker polarity substance. The characteristics of this bioactive substance were studied. The results showed that this bioactive metabolite did not have volatility. It was acid and heat and UV stable.5.The bioactivity sustenance had a certain degree inhibition to mycelium. The results of mycelium growth rate showed that the value of EC50 against Dothiorella gregaias and Valsa sordida and Valsa mali were 0.0076ml/ml and 0.0061ml/ml and 0.0043ml/ml respectively. The value of EC50 against Fusarium spp and Colletotrichum gloeosporioides were 0.0531ml/ml and 0.0497ml/ml respectively.6.It was proved through orthogonal experiments that the optimumcul fermental conditions for producing the antibiotic active substance were soybean cake(10g/L)and peptone(3g/L)and glucose(10g/L) and NaCl(2.5g/L)and FeSO4(0.01g/L) and pH≈8.00 and inoculate with 48 hours seed-age and 2% inocula and culture for 200 ml 6days, 150 dr/min.7. By means of observation on substrate mycelium, aerial mycelium, spore and rothrix , cultural characteristics,Biochemical and physiological characteristics, NO.268 was primarily identified as a variety of Streptomyces griseochromogenes.