Abstract: It is of great significance to grow the strain into the appropriate pellet form for the industrial fermentation of filamentous fungi. The morphology control in the seed culture process of Rhizopus oryzae in the 5L stirring bioreactor was investigated. The optimal conditions for the pellet formation were as follows：the spore concentration in the fermentor should be controlled in the range of （5×104）～（8.3×104）/mL, the best agitation speed was 350r/min, the best pH in the medium was maintained at 2.80, and by using residual glucose concentration of 20g/L as an empirical value the best seed age was determined at 52h. In this way, the smooth compact pellets with the diameter around 1mm were obtained. Fermentation results showed that the pellet morphology was more beneficial to the fumaric acid production than the filamentous morphology.

摘要： 发酵过程中控制菌体为适宜的菌球形态对于丝状真菌发酵的工业化放大具有重要的研究意义。本文针对米根霉在5 L发酵罐上种子培养过程中的形态学控制进行了研究，确定了最适宜形成菌球的培养条件分别为：控制发酵罐内的孢子浓度在5×104～8.3×104/mL的范围内，搅拌转速350 r/min，种子液 pH值稳定在2.80，以20g/L的葡萄糖浓度作为最佳种龄的经验值确定种子培养时间为52 h。该条件下可以获得表面光滑的直径约为1 mm的结实菌体。发酵结果表明，相比于絮状形态，菌球形态更有利于富马酸的生成。