The Identification Of Streptomyces Sp JD211and Studies On Its Secondary Metabolites

Actinomycetes are important microbial resources in the world, in this thesis, a strainof actinomycetes (JD211) isolated from Davidia involucrate in Lushan, JiangXi provincechose as the main research object. The growth characteristics, taxonomic status,fermentation condition optimization, the antifungal activity, isolation and identified ofbioactivity compounds from strain JD211metabolites were studied. The main results andconclusions were outlined as follows:1. Based on the results of morphological characteristics, biology characteristics,biochemical and physiological characteristics and16S rDNA sequence of the strain JD211,it was identified as Streptomyces naraensis, named as Streptomyces JD211.2. The fermentation medium and cultivation conditions of Streptomyces JD211wasoptimized investigated by single experiments. Filter by media types, carbon and nitrogensources screening. The optimize composition of the Streptomyces JD211use carbon fromhigh to low is glycerol>sucrose=soluble starch> starch> glucose> lactose> maltose.The Streptomyces JD211use nitrogen from high to low is hormone> yeast ectract>nitrate> beef extract> urea> peptone. The optimize composition of fermentation mediumwere as follows: glycerol30g/L, yeast extract10g/L, ammonium sulfate5g/L, NaCl5g/L,CaCO33.5g/L; and the optimum fermentation condition: medium volume50mL/250mL、initial pH7.0、inculation volume7.5%、cultivation temperature30℃、cultivation time144h.After optimization, the bacteria growth mass and antibiotic activity of Streptomyces JD211improved by62.49%and23.53%.3. The fungicidal activities of the fermentation product of Streptomyces JD211wereevaluated by mycelium growth rate. The bioassay results showed that fermentation brothhave bioactivity against12test plant pathogenic fungi. In particular, over90%myceliumgrowth inhibition rate on plant pathogenic fungi Magnaporthe pryzae、 Phytophthoraparasitica and Rhizopus. The bacteriostatic mechanism of the fermentation broth ofStreptomyces JD211against plant pathogenic fungi were initially researched. The resultsshowed that the antibacterial could deformity and damaged the mycelium of test plantpathogenic fungi. In addition, the antibacterial substances could significantly inhibited thegrowth of conidiophores.4. The purification of the antimicrobial substances produced strain JD211was studied.The activities products of Streptomyces JD211was determine as glutarimide antibiotics.The antimicrobial substances were diffluent in n-butanol and ethyl acetate; slightly solublein chloroform; dissoluble in the weak polar solvent such as benzene、ether and petroleum. The results of silica column chromatography experimental showed that use1:5petroleumether: ethyl acetate as the eluent have the greatest antibacterial activity. The results of TLCexperimental showed that Rf value of0.53and0.6have the antibacterial activity. TheLC-MS/MS results showed that samples3,4and Cycloheximide has the same molecularweighe:281.25. The MRM results showed that sample3,4contains a large amount ofactive substance. The infrared spectra results showed that Cycloheximide and sample3aresame as glutarimide antibiotics. They all have the unique glutaryl six-membered ring. It’sdetermined that sample3is a glutarimide antibiotics. But Cycloheximide and sample3might have some differences in the structure.5. Stability test of activities products of Streptomyces JD211had been carried out toacid, alkali, temperature and ultraviolet radiation. The activities products of StreptomycesJD211were stable to temperature and ultraviolet radiation. The activities products wasstable under pH7.0, but the inhibition rate were lower obviously under alkali.