樟疫霉拮抗链霉菌S-03菌株发酵条件优化及其稳定性探究

Fermentation Condition Optimization and Stability of Streptomyces S-03 Strain,a Phytophthora cinnamomi Antagonist

樟疫霉(Phytophthora cinnamomi)可以侵染植物,导致根腐病。前期研究发现,阿劳琼链霉菌(Streptomyces araujoniae) S-03对根腐病病原菌樟疫霉有较好的抑制作用,但该菌的发酵条件、发酵液的稳定性和化学性质还不清楚。本研究采用单因素和正交试验设计对S-03菌株的发酵条件进行优化,并对发酵产物的稳定性及化学性质进行研究。结果显示:优化后的培养基抑制率提高了89.72%;配方为可溶性淀粉45g/L、黄豆饼粉20g/L、(NH;);SO;1 g/L、KCl 1 g/L;发酵条件为起始pH 8、接种量2%、装液量75 mL/250 mL、发酵时间7 d、发酵温度28℃、转速160 r/min。抑菌活性物质能耐受酸性条件但对碱性环境敏感,不能耐受60℃以上高温,对紫外光照有很好的稳定性。经正丁醇萃取可获得较大量的抑菌活性物质,表明活性产物的化学极性较低。菌株S-03发酵液能有效抑制疫霉菌丝生长,使其皱缩干瘪,对离体植物叶片也有较强的防治效果,防效达到80.00%。研究结果表明,菌株S-03发酵液能有效抑制樟疫霉生长,活性物质有较好的稳定性及离体叶片防治效果,具有良好的应用前景。

Phytophthora cinnamomi can infect plants, causing root rot. Previous studies have found that Streptomyces araujoniae S-03 had a good inhibitory effect on the root rot pathogen, but the fermentation conditions, stability and chemical properties of the fermentation broth are still unclear. Herein, the single factor and orthogonal experimental design were used to optimize the fermentation conditions of strain S-03,and the stability and chemical properties of its fermentation products were explored. The results showed that the optimized medium increased the inhibition rate by 89.72%. The medium contained soluble starch 45 g/L,soybean meal 20 g/L,(NH;);SO;1 g/L, and KCl 1 g/L. The optimized fermentation conditions included initial pH 8, inoculum volume 2%, liquid filling volume 75 mL/250 mL, fermentation time 7 d, fermentation temperature 28 °C, and rotation speed 160 r/min. Antifungal active substances could withstand acidic conditions but were sensitive to alkaline environments. Meanwhile, they could not tolerate high temperatures above 60 ℃,and had good stability to ultraviolet light. A large amount of antifungal active substances could be obtained by n-butanol extraction, indicating low chemical polarity of the active products. The fermentation broth of strain S-03 could effectively inhibit the growth of P. cinnamomi hyphae, making them shrink and shrivel, and the strong control effect on isolated plant leaves reached 80.00%. The results demonstrated that the fermentation broth of strain S-03 can effectively inhibit the growth of P. cinnamomi and that the active substances have good stability and control effect on isolated leaves, indicating a good application prospect.