苏芸金杆菌发酵水平与溶氧关系的研究

在对苏芸金杆菌(Bacillus thuringiensis,B.t)发酵生理特性研究的基础上,证实了B.t发酵过程中发酵液中溶氧(DO)浓度是影响发酵永平的关键因素。在12L玻璃发酵罐试验中,通过优化供氧条件,使发酵水平(活芽孢数)得以提高。如搅拌转速由300r/min增加至600r/min,菌数可提高47.1%;适当增加搅拌器直径,菌数可提高13.6%。发酵全过程采用变转速控制,菌数比300 r/min定速控制提高36%,轴功耗较600r/min定速控制节约50%。在20t发酵罐放大试验中,调整内部结构后,使溶氧水平提高,菌数比改造前增加了15.3%。

Relationship of Bacillus Thuringiensis Fermentation Level and Dissolved Oxygen

Based the fermentation physiology study for Bacillus thuringiensis (B.t), The results show that the concentration of dissolved oxygen (DO) in the fermentation broth is the key factor affecting fermentation level in B.t fermentation process. In the experiments of 12 L glass fermentor, the fermentation level (number of living gemmae) increases through improving the condition of oxygen supply. For example, raising the agitation speed from 300 r/min to 600 r/min, the unmber of bacteria (NB) will be increased 47.1%. Enlarging the agitator diameter properly, NB will be increased 13.6%. When the speed control in the whole fermentation process is variable, NB is increased 36% in comparing with that of the constant speed control (CSC). Furthermore, the shaft Power assumption is saved 50% in comparing with that in the CSC at 600 r/min. In the amplified experiments of 20 m~3 fermentor, after adjusting the inner structure; DO is increased and NB is also increased 15.3% in comparing with that in the original structure.