分阶段调控关键因素提高白僵菌固态发酵产孢量

Improvement of sporulation by Beauveria bassiana in solid state fermentation using stage key factors control strategy

采用分阶段调控关键因素策略,对白僵菌固态发酵过程进行优化。优化后最佳发酵模式为:初始含水量为65%,发酵至48 h将含水量调为68%;发酵至20 h和40 h分别适当翻料;0～48h(适应期)发酵温度为25℃,48～108 h(快速生长期)发酵温度为24℃,108～168 h(稳定期)发酵温度为28℃;同时,48～108 h按通气比1:2通气,0～48 h和108～168 h不通气。采用上述关键因素调控策略后,白僵菌固态发酵产孢量达18亿孢子/g(干培养基),与优化前相比产孢量提高约360%,效果显著。

The processes of solid fermentation by Beauveria bassiana were optimized by stage key factors control strategy. After optimization, the optimal fermentation conditions and modes were obtained as follows： the initial water content was 65%, and the water content at 48 h was regulated to 68%. The culture materials were mixed well at 20 h and 40 h, respectively. The temperature of fermentation was controlled at 25℃ during 0 -48 h （ adaptive phase ）, 24℃ during 48 - 108 h （ rapid growth phase ） and 28℃ during 108 - 168 h （ stationary phase ）. The aeration ratio was maintained at 1：2 during 48 -108 h, but without any aeration during 0 -48 h and 108 -168 h. Under the optimum conditions and modes, the sporulation of the B. bassiana in solid-state fermentation could reach to 18 - 109 conidia/g （ dry weight ）, and the sporulation was increased by about 360%.