两阶段搅拌转速控制策略发酵生产柠檬酸

采用3 L机械搅拌式发酵罐研究黑曲霉发酵生产柠檬酸的培养条件,考察了不同梯度的发酵转速对黑曲霉生长、柠檬酸产量以及残糖的影响。结果显示,在固定控制条件下,固定转速500 r/min时发酵情况最好,产酸均达到12.9 g/dL,糖酸转化率为86%,生物量为42.6 g/L。根据实验结果进行了两阶段转速控制发酵,结果产酸为14 g/dL,转化率94.6%。在此基础上进行了分批补料发酵优化,与两阶段搅拌转速控制分批发酵相比,柠檬酸产量(17.2 g/L)提高了22.8%,糖酸转化率(95.5%)提高了2.2%。

Strategy of Two-Stage Agitation Rate for Citric Acid Production

The effects of agitation seed on the growth of Aspergrillus niger CCTCC M2013172, citric acid production,dissolved oxygen and residual sugar were studied in a 3 L batch fermenter in this study. The results revealed that 500 r/min was the relative optimal condition and under this condition the yield of citric acid is 12.9 g/L,the conversion rate is 86% and the biomass is 42.6 g/ L.Base on the result,a two-stage agitation ratecontrolling strategy was proposed,in which agitation rate was controlled at 600 r/min in the first 16 h and then switched to 500 r/min after wards. By this controlling strategy,the yield of citric acid reached 14 g/L,the conversion rate reach to 94.6%. And then the two-stage agitation rate controlling strategy was combined with fed-batch fermentation technology,and the yield of citric acid reached 17.2 g/L,the conversion rate reached 95.5%.