Preliminary Study On Actinomycetes Resource Of Anti-animal Pathogrens From Desert And Saline-alkali Soil Of Xinjiang

In this experiment,412actinomycetes were isolated from typical desert areas and salinesoil in Xinjiang Province were chose as the main research object, and12kinds of animalenteric pathogens as target bacteria were studied. The antimicrobial activity, the taxonomicstatus, isolation of bioactivity compounds from excellent strains metabolites and fermentationcondition optimization were studied. The main results and conclusions were outlined asfollows:(1) This study showed that39.6%actinomycetes have inhibiting activity to8animalpathogens by agar block experiment. These actinomycetes exhibited a higher inhibit activityagainst the gram-positive bacteria compared with the gram-negative bacteria. And26.0%and22.3%of the actinomycetes showed antagonism against bovine Streptococcus agalactiae andswine Staphyloccocus aureus. The strains of inhibition diameter D≥15.0mm were screenedby fermentation liquor experiment, and12kinds of pathogenic bacteria as target bacteria. Theresults were basically identical with agar block experiment. The strains XJ1625and XJ68H02had high antibacterial activity. The inhibition diameters were around30.0mm to thebovine Streptococcus agalactiae and swine Staphyloccocus aureus.(2)11excellent antagonistic strains were obtained and identified through the method ofpolyphasic taxonomy, XJ6-2is Streptomyces coeruleofuscus, XJ1-5-10is Streptomycesfimicarius, XJ2-9is Streptomyces griseoplanus, XJ2-5-1is Streptomyces fradiae, XJ19-11isStreptomyces variabilis, XJ1202is Streptomyces luridus, XJ1625is Streptomycesflavidovirens, XJ2-9-7is Streptomyces kurssanovii, XJ68H02is Streptomyces ferralitis, XJ617is Streptomyces massasporeus. And the sequence similarity of XJ1-6-5was below98.0%,it may be a potential new species, and need further evaluation.(3) With avian Staphyloccocus aureus CVCC548for target bacteria, determined theantibacterial activities by agar diffusion plate method. The result indicated that the strain XJ1625and XJ68H02had a good stability to the pH, temperature, uv and proteinase K, can beextracted by different organic solvent extraction. But the strain XJ68H02had better stabilitythan the strain XJ1625, the active substances extracted more easily, and have higher fermenting liquid titer and smaller MIC. So the strain XJ68H02be used the further research.(4) The fermentation process optimization of strain XJ68H02was tested by orthogonalexperiment. With avian Staphyloccocus aureus CVCC548for target bacteria, by agardiffusion plate method to determine their antibacterial activities. The results showed thatsoybean powder was optimized the fermentation medium, in the seed age of36h, inoculumsize7.0%, initial pH of7.5, cultured132h under35℃, the titer of the strain can reached933.77μg/mL and increased about2.8times.