Dissertation > Excellent graduate degree dissertation topics show

Study on the Screening of Doramectin-producing Strains by Nitrogen Ion Implantation and Optimization of Fermentation

Author: YangShiHong
Tutor: ChenXin;ZhangXiaoLin
School: Wuhan Polytechnic University
Course: Microbial and Biochemical Pharmacy
Keywords: Doramectin Streptomyces avermitilis mutation optimization of fermentation medium precursor
CLC: S859.79
Type: Master's thesis
Year: 2011
Downloads: 10
Quote: 0
Read: Download Dissertation

Abstract


Doramectin,is new macrolide antibiotics and an avermectin derivative with higher and wider antiparasitic activity in veterinary medicine and pesticides,which was biosynthesis by feeding cyclohexanecarboxylic acid in the fermentation process of Streptomyces avermitilis with bkdFGH gene deletion.It is one of the most effective agricultural pesticides and antiparasitic agents with a potential development . In this paper , we studied the screening methods of high doramectin-producing strains with 96-well plates , and selected high doramectin-producing strain with precursor and end-products resistance experiments and N+ mutation . Then , we optimized the fermentation medium.Meanwhile,the effect of precursor on doramectin biosynthesis were researched.The main results were as follows:1.According to screening strain by the precursor resistance experiment,a high doramectin-producing mutant was achieved,which was 60.62% higher than the initial strain.And The minimum inhibiting concentration of CHC was 300μg/μL for this strain.2.According to the mutagenic effects of the high doramectin-producing strain by nitrogen ion implantation with different dosage,the two- summit survival curves was obtained.3.According to the studied on the growth of Streptomyces avermitilis in both solid medium and liquid medium,we found that growth were both good.However,CHC and CaCO3 were insoluble and irreplaceable in the liquid fermentation medium,so use 96-well plates to screen high doramectin-producing strains we must overcome this difficulty.4.Initial studies to optimize carbon and nitrogen sources,inorganic nitrogen sources , inorganic salts and trace elements the doramectin production were performed by single factor experiments and two factor experiment of carbon and nitrogen sources.And the fermentation medium for the strain of XJ-CHC150-17 was optimized by response surface analysis.The results showed that optimum fermentation medium is（g/L）:corn starch 75,dry yeast 18,KCl 1.35,MgSO4 0.16, K2HPO4·3H2O 1.8, FeSO4·7H2O 0.012, Na2Mo4·2H2O 0.045, NH4Cl 0.09,CoCl2·6H2O 0.005,CaCO3 2,pH7.0,and the doramectin yield in the optimum fermentation medium was 103.54μg/mL that increased 1.80 times compared with that using the original medium.5.According to the study of fermentation conditions, the results showed that 30mL medium volume in 250mL shaking flask,initial pH 7.0,seed age 72h,seed inoculum 6% without glass beard,the doramectin production was maximum.6.According to effect of precursor on doramectin biosynthesis,it was suitable for cultivating 48h feeding 300μg/mL CHC.And we found that amino acids inhibited the doramectin biosynthesis obviously meanwhile among low -grade fatty acids sodium propionate as a precursor is superior to other precursor for promoting doramectin biosynthesis . By feeding of 0.1% sodium propionate into the fermentation broth at the 4th day of cultivation,the doramectin production was 139.89μg/mL,38.20% higher than that in the condition without any addition of precursor.7.According to orthognnal design of sodium acetate anhydrous,sodium propinonate and trisodium citrate dehydrate, doramectin yield was increased 9.39%.

Related Dissertations

  1. Study of Mutation and Breeding of Griseofulvin Produccing Strain FS80,TQ927
  2. Breeding of Fungal α-amylase High-producing Strain by Genome Shuffling,TQ925
  3. Study on the Breeding of High Efficient Detoxification Strains and Suggestion Parameters of Solid Fermentation on Cottonseed Meal,S816.6
  4. Incidence and Mechanisms of Insecticide Resistances to Organophosphates and Carbamates in Colorado Potato Beetle, Leptinotarsa Decemlineata (Say),S435.32
  5. Screening, Bio-Characteristics and Biopulping Application of a High Pectin-Degrading Baeterial Strain by Ultraviolet-Ray Mutation,TS713
  6. Preliminary Studies on Constructing Brassica Napus L Mutant Library by EMS Inducement,S565.4
  7. Research on the Mutation Breeding of Flavomycin and Regulation of Fermentation Techniques,TQ920.6
  8. Mutation Inducing Breeding of Avilamycins Production and Optimization of Fermentation Conditions,TQ927
  9. The Study on Breeding and Fermentation Conditions of a Selenium-Riched Yeast and Its Application Research,TS201.25
  10. The Study of Mutation in the CRX Gene Associated with Late-onset Genetic Retinitis Pigmentosa (RP),R774.1
  11. Effect of Single and Double Mutations of Yeast H3K79L、H4K20L on the Function of ELP3 and Expression of SSA3,Q75
  12. Screening of Pigment-free Pullulan High Producing Microorganism and Research of Optimal Culture Media,TQ920
  13. Study on Transformation and Biosynthesis of Saikosaponin in Adventitious Root Culture of Bupleurum Chinense DC.,R284
  14. Influences of Temperature on SCF/c-kit Prolifertation Pathway and Cell Cycle of Rat Spermatogonial Cells Cultured in Vitro,R698
  15. The Significance of Expression and Genetic Mutation of Cx26, Cx32 in the Pathological Skin Scar and Scar Carcinoma,R739.5
  16. CHST6 Mutations and Histopathologic Study in Macular Corneal Dystrophy,R772.2
  17. High glucose in human umbilical vein endothelial cells expression of renin precursor,R543.5
  18. Chinese people early-onset type 2 diabetes , IGT / IFG patients were paired box gene 6 gene mutation / mutation screening,R587.1
  19. Special morphology precursor synthesis route inorganic oxide,TB383.1
  20. To Explore the Value of Plasma NT-proBNP and Hypersensitive C-reactive Protein in Evaluating the Prognosis of the Patients with Acute Coronary Syndrome,R541.4

CLC: > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > Animal Medicine ( Veterinary Medicine) > Veterinary Pharmacology > Veterinary drugs
© 2012 www.DissertationTopic.Net  Mobile