为提高丁酸梭菌的发酵生物量,首先在厌氧瓶水平确定了0 h添加0.2 mmol/L乙醛可以有效提高细胞数,后在10 L发酵罐规模研究了葡萄糖和乙醛共补料策略对丁酸梭菌发酵性能的影响。结果表明:采用葡萄糖和乙醛共补料能获得较高的生物量(11.37×10~8CFU/mL),相对于葡萄糖补料发酵(9.93×10~8CFU/mL)和批发酵(9.39×10~8CFU/mL)分别提高了14.5%和21.1%。发酵8 h时,丁酸和乙酸的比生成速率相对于葡萄糖补料发酵分别降低18.9%和17.3%,而乙醇的比生成速率却提高了9.7%,实现了高生物量和低产酸的相对统一。乙醛的添加使NADH的氧化由丁酸合成途径部分向乙醇合成支路迁移,增强了乙醇的合成效率,降低丁酸、乙酸的积累,提高了丁酸梭菌的生长效率。

In order to improve the biomass of Clostridium butyricum,acetaldehyde addition with an optimized concentration of 0.2 mmol/L at 0 h was first ensured at the anaerobic bottles level,which can significantly increase the biomass,and then,the effects of glucose co-feeding with acetaldehyde strategies on the fermentation characteristics of Clostridium butyricum in a 10 L bioreactor were investigated.The results showed that glucose co-feeding with acetaldehyde enhanced the cell growth(11.37×10~8 CFU/mL),which was 14.5% and 21.1% higher than those of glucose fed-batch culture(9.93×10~8 CFU/mL) and the batch culture(9.39×10~8 CFU/mL).Furthermore,the specific productivity of butyrate and acetic decreased by 18.9% and 17.3%,and the specific productivity of ethanol was increased by 9.7% glucose fed-batch culture,achieving the unity between a higher biomass and a lower acid production simultaneously.The addition of acetaldehyde promoted the NADH oxidation from butyrate biosynthesis pathway to the ethanol biosynthesis branch,which enhanced the ethanol synthesis with the reduced accumulation of butyrate and acetate,and the cell growth efficiency of Clostridium butyricum was improved simultaneously.