一株蓝莓溃疡病拮抗菌发酵条件优化及稳定性研究

Optimization of Fermentation Conditions and Stability of an Antagonistic Strain of Blueberry Canker

为了明确最有利于蓝莓溃疡病生防链霉菌CX3发酵的营养条件和发酵条件,采用碳氮源筛选法确定发酵培养基的最佳碳源、有机氮源和无机氮源,通过正交设计试验确定碳、氮源的最佳配比,同时,采用单因素法对优化后的CX3发酵液的稳定性进行测定。优化后的发酵培养基配方为:葡萄糖60 g,花生饼粉40 g,硝酸钾4 g,氯化钠4 g,碳酸钙4 g,水1000 mL,pH 7.0。最佳发酵条件为:发酵温度28℃,摇床转速150 r·min-1,初始pH为7、发酵时间6 d、菌株种龄6 d、种子液与培养基体积比5%。优化前的抑菌直径是15.93 mm,优化后是24.88 mm,优化后的抑菌圈直径增加8.95 mm。发酵液稳定性测定结果表明:发酵液耐碱但对pH小于4的酸性环境敏感;对温度耐受性好,121℃时发酵液失活,易贮存,常温保存15 d,发酵液亦可保持较好的抑菌活性。本研究筛选获得的拮抗菌株CX3的发酵培养基条件经优化后,发酵液抑菌能力显著提高,且发酵液的理化性质稳定,开发前景广阔,为蓝莓溃疡病的生物防治提供了新的生防因子。

In order to clarify the nutrient conditions and fermentation conditions which were most conducive to the fermentation of blueberry ulcer disease-resistant Streptomyces CX3,the carbon and nitrogen source screening method was used to determine the best carbon source,organic nitrogen source and inorganic nitrogen source of the fermentation medium,the optimal ratio of carbon and nitrogen sources were determined by orthogonal design experiments,and at the same time,the stability of the optimized CX3 fermentation broth was determined by the single factor method.The optimized fermentation medium formula was glucose 60 g,peanut meal 40 g,potassium nitrate 4 g,sodium chloride 4 g,calcium carbonate 4 g,water 1000 mL,pH 7.0.The optimal fermentation conditions were fermentation temperature 28℃,shaker speed 150 r·min-1,initial pH 7,fermentation time 6 d,strain age 6 d,and the volume ratio of seed liquid to medium 5%.The inhibitory diameter before optimization was 15.93 mm,and after optimization was 24.88 mm,the diameter of the inhibition zone after optimization increased by 8.95 mm.The results of the fermentation broth stability test showed that the fermentation broth was alkali-resistant but sensitive to acidic environments with a pH of less than 4.It had good temperature tolerance,the fermentation broth was inactivated at 121℃and was easy to store,it could be stored at room temperature for 15 days,and the fermentation broth could also be maintained good antibacterial activity.After the optimization of the fermentation medium conditions of the antagonistic strain CX3 obtained in this study,the antibacterial ability of the fermentation broth was significantly improved,and the physical and chemical properties of the fermentation broth were stable.The development prospects are broad,which provides a new biocontrol factor for the biological control of blueberry canker.