对蜱致病性球孢白僵菌培养条件的优化

Optimization of cultural conditions of Beauveria bassiana pathogenic for ticks

摘要:

对前期筛选得到的具有生防潜力的杀蜱真菌Beauveria bassiana AT17菌株进行相关生物学性状的研究, 建立一套规范的实验室培养的技术和方法, 同时对其液固双相发酵技术进行优化, 在于提供优质高效的生防材料, 为其真菌制剂的规模化生产提供实践和理论基础。通过采用单因素筛选方案对其最适基础培养基、温度、pH值、碳源、氮源、微量元素及液固双相发酵配方进行研究, 发现该菌株在PDA、PPDA、PDAY、SDAY、SMAY 5种培养基上均能较好生长, 在PDA上生长最快, 在PDAY上产孢量最大。温度对菌丝的生长和产孢影响显著, 25 °C菌丝生长最快, 且产孢量最大。B. bassiana AT17菌株在pH 4?10范围内均可生长, 在偏碱性环境内生长最快, 在pH 5?6的偏酸性环境内产孢量最大。综合评价真菌各项指标后, 葡萄糖和酵母粉为菌丝生长和产孢的最佳碳源和氮源, 固体物料麦麸+玉米粉+米粉与基础培养液3/4 SDAY按2:1均匀混合后, 添加0.05% K+可作为菌株固体发酵的最佳物料配方组合。

Abstract:

The aim of this study was to establish and optimize standard laboratory techniques for cultivation and fermentation of a strain of Beauveria bassiana (B. bassiana AT17), which has shown potential biological activity against ticks. This will provide practical and experimental supports for the further research on preparation of biocontrol agents. Condition optimization was conducted by single factor experiment. The factors studied were basic culture medium, temperature, pH, carbon sources, nitrogen sources, microelements and liquid fermentation medium. The results showed that B. bassiana AT17 could grow well on PDA, PPDA, PDAY, SDAY and SMAY medium. Comparatively, B. bassiana AT17 had the fastest growth on PDA and the highest spore yields on PDAY. Temperature was the major factor that affects on growth speed and yields of B. bassiana AT17. It showed that 25 °C was the optimal temperature for both hyphal growth and the sporulation. B. bassiana AT17 could grow at pH 4?10 with the fastest growth in alkali condition, and produce optimal sporulation at pH 5?6. Based on all of fungal indexes, glucose and yeast were the best carbon and nitrogen sources. The best solid fermentation medium was wheat bran+indian meal+rice flour mixed with 3/4 SDAY containing suitable K+ in proportion of 2:1.