Combination Of Drug-Resistant To Breeding High Qinlingmycin-Producing Strains And Research Of The Optimization Of Fermentations

Streptomyces qinlingensis sp.nov. was isolated by pesticide institute of Northwest A&F University from the soil of qinling mountainous areas in shaanxi province, China. Earlier stage studies showed that the fermentation products of the strain of Streptomyces qinlingensis sp.nov exhibited strong fungicidal activity against pathogenic fungi and bacteria., but In the fermentation product the biological activity material content is very low, limited to its further research and the development. In order to development the potential value of Streptomyces qinlingensis sp.nov, from three aspects to research it:first is combination drug-resistance breeding of high qinlingmycin-producing strain ; second is optimization fermentative condition of high production strain; third is feeding precursors of high production strain. The main results are as follows:(1) The application of combination drug-resistance breeding of high qinlingmycin produ- cing strain'findings indicated that through the combination streptomycin and gentamicin resistance to selective breeding high producting strains is one effective breeding method. Through combination drug-resistance breeding, three high producing strains named GS-4-04, GS-4-05 and GS-4-06 were obtained. The fermentation broth of GS-4-04, GS-4-05 and GS-4- 06 exhibited higher fungicidal activity against 5 species of bacterium and 4 species of fungus compared with the fermentation of the primitive strain, GS-4-04's antibacterial activity increased 20.1 to 28.9 percent, and its pathogenic fungi toxicity is 0.4 to 2.4 times to the original strain ; GS-4-05's antibacterial activity increased 19.4 to 28.9 percent, and its pathogenic fungi toxicity is 1.7 to 4.6 times to the original strain ; GS-4-06's antibacterial activity increased 25.0 to 33.3 percent, and its pathogenic fungi toxicity is 1.5 to 5.4 times to the original strain.(2) The fermentation optimizations to high qinlingmycin-producing strains showed that, the strain of GS-4-04's optimal fermentative condition was: 5g/Lglucose, 10g/Lmillet, 3g/L pepton, 2g/L Ca²⁺,and the optimal pH was 7.0,most suitable volume of cultivated liquid was100mL,vaccination quantity was 10%,fermentation time was 96h-120h;the strain of GS-4-05'optimal fermentative condition was: 15g/Lglucose, 5g/Lmillet, 4.5g/Lpepton, 2g/L Ca²⁺,and the optimal pH was 7.0,most suitable volume of cultivated liquid was100mL,vaccination quantity was 10%,fermentation time was 96h-120h;the strain of GS-4-06'optimal fermentative condition was: 5g/L glucose, 15g/Lmillet, 4.5g/Lpepton, 2.5g/L Ca²⁺,and the optimal pH was 7.0,most suitable volume of cultivated liquid was100mL,vaccin- ation quantity was 10%,fermentation time was 96h-120h..(3) The research which feeding the precursors to the high production strains indicated that: during GS-4-04's fermentation 24h～60h to added 0.05 percent the L-arginine, GS-4-05's fermentation 36h～48h to added 0.1 percent the L-arginine, GS-4-06's fermentation 48h～60h to added 0.1 percent the L-arginine, after fermentation to 96h the antibacterial activity of the three resistant mutant strains'fermentation compared with the no precursor substances fermented liquid has increased.