柠檬酸连续流加补料发酵的工业化研究

The industrialization study on citric acid continuous flow and supplementary food fermentation

针对传统柠檬酸发酵工艺的不足,在300 m3新型空气能发酵罐上,对黑曲霉(Aspergillus niger)Wm1-016连续流加补料发酵生产柠檬酸进行了工业化研究,优化了培养条件和控制方法,并确定了最佳的补料条件参数。结果表明:采用孢子直接接种和一罐式发酵,菌种生长期和产酸期采用2段控温方式,即0~32 h控制在(39±1)℃、32 h以后控制为(36±1)℃;采用3D射流空气分布器进行3段风量控制,即菌种生长期1∶0.15vvm、补料期1∶0.18 vvm、补料结束后1∶0.15 vvm。流加计量罐式补料装置,补料流加速度为0.1~4.0 m3/h,最适初糖浓度80~120 g/L,最佳补料培养基为含葡萄糖浓度500 g/L的淀粉糖,并加入0.03%的(NH4)2SO4。在以上优化条件下,柠檬酸产量从146.8 g/L提高到180.1 g/L,提高了22.7%。

A continuous flow and supplementary food fermentation method for citric acid production by Aspergillus niger Wm1-016 was proposed and studied in a 300 m new air source fermenter to overcome the disadvantage of conventional citric acid fermentation method. The industrialization study was carried out in one-fermenter fermentation.The direction spore inoculating was adapted. The subdivision control of temperature was applied and the culture temperature for the growth phase( 0 ~ 32 h) and acid production phase( after 32 h) were( 39 ± 1) ℃ and( 36 ± 1) ℃,respectively. The 3D jet flow air distributor was used and the ventilation rate for the growth phase,fed-batch phase and end of fermentation were 1∶ 0. 15 vvm,1∶ 0. 18 vvm,and 1∶ 0. 15 vvm. A fed-measurement tank was added and the flow acceleration was set to be 0. 1 ~ 4. 0 m3/h. The optimal initial sugar concentration was 80 ~ 120 g /L,and the optimum fed-batch medium was the starch sugar with 500 g /L glucose and 0. 03%( NH4)2SO4. In general,the citric acid production was increased from 146. 8 g /L to 180. 1 g /L,which was increased about 22. 7%.