一株拮抗香蕉枯萎病芽胞杆菌的液体发酵培养基优化

Optimization of Liquid Fermentation Medium of an Antagonistic Bacillus sp. against Banana Fusarium Wilt

筛选原料廉价且适合芽胞杆菌HD34分泌拮抗香蕉尖孢镰刀菌古巴转化型4号生理小种(Fusarium oxysporum f.sp.cubense(FOC),race 4)活性物质的液体发酵培养基,为后续芽胞杆菌HD34大规模液体发酵奠定基础。通过拮抗实验,以抑菌圈直径大小为指标找出芽胞杆菌HD34液体发酵基础培养基,采用正交试验确定液体发酵培养基成分的比例,利用显微观察拮抗物质对病原菌的影响。适合芽胞杆菌HD34生长的基础培养基成分为玉米粉、大豆粉、磷酸氢二钠,金属离子影响不明显,HD34在正交9号组合A3B3C2(玉米粉2%,豆粉1%,Na_2HPO40.1%)表现出最强活性,抑菌圈直径达到27.60 mm,显微镜观察发现芽胞杆菌HD34的发酵滤液对香蕉枯萎病原菌菌丝具有致畸作用。芽胞杆菌HD34在正交9号组合(A3B3C2)培养条件下,发酵滤液对病原菌菌丝具有破坏作用,该液体发酵培养基具有潜在应用推广价值。

T he purpose of this experi ment is to find a cheap liquid fermentation medium that is suitable for Bacillus sp. HD34 to produce antagonistic substances against Fusarium oxysporum f. sp. cubense(FOC) that can cause Fusarium wilt of banana, which can lay the foundation for large-scale liquid fermentation of Bacillus sp. HD34 in future. The composition of liquid fermentation medium of Bacillus sp. HD34 was determined by the antagonistic experiment with the inhibition zone as indicators combined with the effect of the active antimicrobial substances against pathogen was based on microscopic observation, using orthogonal test to determine the proportion of the composition of liquid fermentation medium. The most suitable liquid fermentation medium for the growth of Bacillus sp. HD34 was formed from corn flour, soybean meal, disodium hydrogen phosphate, the effect of metal ions was not obvious. Bacillus sp. HD34 showed the strongest antimicrobial activity in 9 orthogonal combination A3B3C2(Corn Flour 2%, Bean Flour 1%, Dibasic Sodium Phosphate 0.1%), the inhibition zone was 27.60 mm. The fermentation liquor of Bacillus sp. HD34 had destructive effects on the pathogen hyphae by microscopic observation. Under the condition of 9 orthogonal combination(A3B3C2), the fermentation broth of Bacillus sp.HD34 showed destructive effects on the pathogen hyphae,which has potential application promotion value.