Primary Studies On Actinomycete M34 And Separation Of Antimicrobial In Gredients From The Fermentation Broth

Actinomycete sp.strain M34,isolated from soil samples Mountain Shizi of Huazhong Agricultural University,has been studied on strain identification, antimicrobial activity,metabolites stability and extraction and purification.The results are as follows:1.Accordin g to morpholo gical,physiolo gical and biochemical characteristics of strain M34,it was identified as the taupes of Actinomycete.2.By means of mycelium growth rate method,the results showed that the effective inhibition rate for Bipolaria maydis and Sclerotinia sclerotiorum could reach up to 93.2%and 90.3%,respectively.The bioassay results showed that the fermentation broth of strain M34 had more than 80%inhibition rates against Rhizoctonia solani,Colletotrichum gloeosporioides;more than 70%inhibition rate against Thielaviopsis paradoxa,Gibberella zeae,Botrytis cinerea and Penicillium italicum.By means of a gar diffusion method,the fermentation broth of strain M34 (31℃,36h) a gainst A grobacterium tumefaciens,Staphylococcus aureus had obvious inhibitive effect,the diameters of inhibition zones were 31 mm and 23 mm, respectively;but the diameters of inhibition zones against Bacillus thurin giensi, Rhodococcus facian,Agrobacterium rhizogens were only 17mm,15mm,12mm, respectively;the fermentation broth of had no inhibitive effect against Ralstonia solanacearum.The results of potted test indicated that the effective prevention and cure rate for Sclerotinia sclerotiorum.Were 76.01%and 55.13%,respectively.3.The results of the stability tests indicated that antimicrobial activity of fermentation broth had a few varieties when strain M34 was successively cultivated 10 generations;the diameter of inhibition zone of the 10^th generations had reduced 37.5%(9mm).And it was unstable to temperature,the diameters of inhibition zones had minished 8.9%when heated for 30 min,the acyivity had obvious decline.And it was also unstable to acid,at room temperature,the activity of active in gredient produced by strain M34 had obvious decline except pH6-8.But it was stable to UV radiation. 4.The results of pH paper chromatography and paper electrophoresis indicated that the bioactive substances were neutral,Doskochilova Solvent System identification showed that the paper chromatography of the the bioactive substances of the fermentation broth was resemble to a kind of the actinomycins.