柑橘内生放线菌CR20发酵培养基的优化

Optimization of fermentation medium for endophytic actinomycete CR20 from citrus

从柑橘根部分离得到1株对多种植物病原菌具有拮抗活性的放线菌菌株CR20,经鉴定属于链霉菌(Streptomyces sp.)。为提高该菌株产生抗生素的能力,通过单次单因子试验和正交试验,对其发酵培养基进行优化筛选,获得最佳培养基配方:葡萄糖1.5%、淀粉1%、花生饼粉3%、(NH4)2SO41%、Na Cl 0.4%、CaCO30.2%、Fe SO4·7H2O 0.1%、KH2PO40.1%,优化后的发酵培养基对柑橘炭疽病菌的抑制率达到84.66%,比初始发酵培养基提高130.18%。为进一步明确菌株CR20的最佳发酵时间,采用优化后的培养基配方,利用5 L全自动发酵罐对其进行培养,获得最佳发酵时间为96 h。

Endophytic actinomycete CR20 with antagonistic effect on many plant pathogens was isolated from the root of citrus,it was identified as Streptomyces sp.In order to improve the antibiotic producing ability of CR20,the fermen-tation medium was optimized using one-factor-at-a-time and orthogonal test.The results showed that culture medium containing 1.5%glucose, 1%soluble starch, 3%peanut powder, 1%（ NH4 ） 2 SO4 , 0.4%NaCl, 0.2%CaCO3 , 0.1%FeSO4· 7H2 O and 0.1%KH2 PO4 was the best, and the inhibition rate of Colletotrichum gloeosporioides from citrus reached to 84.66%and was 1.3 times higher than of that before optimization.Based on the optimized medi-um,the optimum fermentation time of the strain CR20 is 96 h in 5 L automatic fermentor.