Gao Yi-Ping, Shi De-Xiang, Li Yuan-Hao, He Xiong Zhao, Wang Xiao-Yun, Lin Kai, Zheng Xia-Lin
Guangxi Key Laboratory of Agro-Environment and Agric-Products Safety, College of Agriculture, Guangxi University, Nanning 530004, China.
School of Agriculture and Environment, Massey University, Private Bag, Palmerston North 4410, New Zealand.
J Fungi (Basel). 2025 Mar 5;11(3):202. doi: 10.3390/jof11030202.
PfBb is a new strain with high host specificity to the target pest . We conducted a series of experiments to optimize the biphasic fermentation system of PfBb by screening the medium compositions and fermentation environmental conditions in both liquid and solid fermentations. In the liquid fermentation, glucose and yeast extract with a C:N ratio of 17:1 were the optimal carbon and nitrogen sources, respectively, for PfBb mycelium growth and blastospore production, and liquid fermentation with an inoculation concentration of 1 × 10/mL and an inoculum content of 50 mL conidial suspension, at 180 rpm/min rotation speed, pH 7 and 26 °C, favored mycelium growth. However, additional trace elements did not significantly improve liquid fermentation. In the solid fermentation, wheat bran and chaff at a ratio of 8:2 were identified as the best substrates that facilitated PfBb sporulation and conidial germination, and optimal substrates with 20% inoculum content, 50% water content, and 3-day fermentation in darkness had the highest conidia yield. The resulting conidia, stored at -20, 4, and 20 °C for one year, did not significantly change the water content, and with prolonged storage duration, conidial germination was significantly higher at -20 and 4 °C. Moreover, conidia stored at 4 °C for one year maintained its validity and virulence, which were toxic to all instar larvae of . Our results provide essential support for the commercial production of PfBb-based biopesticides.
PfBb是一种对目标害虫具有高宿主特异性的新菌株。我们进行了一系列实验，通过筛选液体和固体发酵中的培养基成分和发酵环境条件来优化PfBb的双相发酵系统。在液体发酵中，碳氮比为17:1的葡萄糖和酵母提取物分别是PfBb菌丝体生长和芽生孢子产生的最佳碳源和氮源，接种浓度为1×10/mL、接种物含量为50 mL分生孢子悬液、转速为180 rpm/min、pH值为7且温度为26°C的液体发酵有利于菌丝体生长。然而，额外的微量元素并没有显著改善液体发酵。在固体发酵中，8:2比例的麦麸和谷壳被确定为促进PfBb产孢和分生孢子萌发的最佳底物，接种物含量为20%、含水量为50%且在黑暗中发酵3天的最佳底物分生孢子产量最高。所得分生孢子在-20、4和20°C下储存一年，含水量没有显著变化，并且随着储存时间延长，在-20和4°C下分生孢子萌发率显著更高。此外，在4°C下储存一年的分生孢子保持其有效性和毒力，对[目标害虫名称]的所有龄期幼虫都有毒性。我们的结果为基于PfBb的生物农药的商业化生产提供了重要支持。
