Streening Of Actinomycetes With Antagonistic Activity From The Soil And Study On Its Metabolites

The primary studies on screening of actinomycetes from 26sample in soil.126 strains of actinomycetes were separated. From the screening of the fungicidal activities, we found 1 strain named S76, the metabolites of which had strong fungicidal activities. Chemical constituents also studied in its metabolites. The main results are as follows:1 26 strains with high antibacterial activity were obtained by antagonistic activity in plate. By means of mycelium growth rate, the fermentation products of the 26 strains had a certain degree fungicidal activity. Most of fermentation products acted on Alernaria longipes, Fusarium bulbigenum, Macrophoma kawatsukai and Fusarium solani. 22 Strains'inhibition rate beyond 70% against Alernaria longipes, and 15 in excess of 70% against Fusarium bulbigenum, Macrophoma kawatsukai and Fusarium solani.2 The result of bioactivity showed that, the fermentation product of S76 had very strong inhibition against many familiar microorganisms on agriculture in vitro or in vivo. The results of mycelium growth rate showed that the fermentation broth of S76 exhibited more than 90% inhibiting efficacy against most of tested fungi, against Macrophoma kawatsukai, Fusarium solani achieved 100% for example. The result of spore germination indicated that the inhibition rate of the culture against Exserohilum turcicum, Colletotrichum gloeosporioides and Cytospora sp. were 75.9%, 70.2%, and 74.4%. The inhibition zone of restrain Escherichia coli, Staphylococcus aureus, Bacillus subtilisand Caudida sp. were 21cm, 23cm, 20cm and 25cm.The result of pot test proved that the fermentation of S76 indicated 87.0% of protective efficacy and 76.9% for therapy。3 By means of observation on substrate mycelium, aerial mycelium, spore and sporothrix, Culture characteristics, Biochemical and physiological characteristics, S76 strain was primarily identified as Streptomyces.4 6 compounds were obtained from the secondary metabolites of S76 by silica gel-column chromatogram and preparation-TLC. 3 compounds'structures were identified on the analysis of the chemical reaction and their spectral data(MS, 1H NMR, 13C NMR).It isβ-sitosterol(Ⅴ),bis(2-ethylhexyl) phthalate(Ⅰ) and 2,5-dihydroxyphenylacetic acid(Ⅳ).