基于活细胞量测量的利福霉素发酵过程氮源优化策略

Studies on the Measurement of Viable Biomass in the Optimization of Rifamycins SV Fermentation Process

在发酵生产利福霉素SV的过程中,其菌丝体的生长代谢情况及产物发酵合成都与有活力的菌丝量密切相关。介绍了在线活细胞传感仪测定活细胞量的方法,它利用细胞的介电特性,能够排除发酵液中固含物的干扰,测得的电容值与活细胞浓度呈线性相关,可以作为工艺优化过程中的关键参数。通过电容变化反映的前期生长出现的二次生长现象,进行了通过使用迟效氮源豆饼粉代替了原培养基中价格昂贵的速效氮源蛋白胨,成功消除了发酵前期由于氮源利用转换造成的生长停滞期,利用豆饼粉情况下培养前期的OUR和CER达到了14.8和15.3 mmol/L/h,明显高于利用速效氮源蛋白胨A组的8.6和11.3 mmol/L/h,保证了持续较高的比生长速率,对于促进菌体的氧消耗速率的增加和维持有着重要的作用,明显有利于利福霉素的合成与速率的维持,氮源替代组的发酵效价达到了5969±19 U/ml,与对照组(5030±17U/ml)相比显著提升发酵单位18.7%以上。

The amount of viable biomass is an important physiological parameter,which is correlated with the cell growth,metabolism and productivity during the rifamycins SV fermentation process. The measurement of viable biomass was studied employing on-line Biomass Monitor. It was able to utilize the dielectric properties of cells,and the capacitance measurement was correlated well with the viable biomass concentration excluding the interference of solid materials. At the same time, there was close connections among the capacitance measurement,OUR,CER and mycelial morphology. The diauxic growth phenomenon in the former fermentation was detected using capacitance detection,and the slow-release nitrogen source soyben powder instead of the original expensive fast-release nitrogen source of peptone was used for rifamycins SV fermentation,successfully eliminated the diauxic growth caused by nitrogen source using the conversion of stagnation,the physiological parameters of OUR and CER reached and maintained at 14. 8 and 15. 3 mmol /L /h at early growth phase,significantly higher than that under peptone conditions for only 8. 6 and 11. 3 mmol /L /h,which promote the continued higher rifamycin SV biosynthesis,the fermentation titer reached to 5969 ＋ 19 U /ml,which was18. 7% higher than that of control（5030 ＋ 17 U /ml）.