Screening Of Multi-antibiotic Resistances Actinomycetes And Analysis On Feimentation Products

Screening of multi-antibiotic resistances actinomycetes is a efficient method with strong purpose.3 kinds of antibiotics were useed for screen the actinomycetes isolated from soil samples in this work,in order to provide a convenient and efficient way for strain screening works.In this work,after soil samples from 4 different districts were pretreated,the screening of actinomycetes were carried out on the isolation medium plus 2μg/mL penicillin and 75μg/mL K2Cr2O7. 20 actinomycetes were got.And then 3 kinds of antibiotics (streptomycin, gentamicin and rifampicin) were used to isolate these 20 actinomycetes, and gained an actinomycete strain which performed 40μg/mL streptomycin, 10μg/mL gentamicin, 150μg/mL rifampicin-resistances. This actinomycete was named the No.1 actinomycete.Mycelium shape,mycelium concentration,pH value and inhibitory activity on Bacillus subtilis and Micrococcus luteus of No.1 actinomycete were studied. And the optimal fermetation period was determined as 10 days by investigating the fermetation condition and active component production.Bacillus subtilis (ATCC 6633) and Micrococcusluteus (ATCC 9341) were treated as bioassay -guided,which were uesd to determinated the bioactivity of supernatant and mycelium extract.Use vernier to determinate the inhibition zones.The reasults showed that , supernatant and mycelium extract of No.1 actinomycete have antibacterial activity to Bacillus subtilis and Micrococcusluteus both.The antibacterial activity to Micrococcusluteus is higher.Supernatant and mycelium extract were used to react with asparagine synthetase. The reasults showed that both supernatant and mycelium extract had high inhibitory activity. The inhibitory activity of supernatant was higher than mycelium extract.Supernatant and mycelium extract were studied by measuring the temperature and acidity-alkalinity stability. The reasults showed that the activity of supernatant was significantly effected by the temperature and the pH.Contrarily the activity of mycelium extract was not effectedThis No.1 actinomycete strain was identified as Streptomyces based on its morphological and physiological properties, 16SrDNA sequence and Blast analysis. The reasults showed that the similarity of 16SrDNA of between No.1 actinomycete and Streptomyces griseus is 99 %.