电容法在线活细胞量传感器在黑曲霉带渣发酵生产柠檬酸中的应用

Study on Online Capacitance Viable-Cell Mass Monitoring in Citric Acid Fermentation by Aspergillus niger in Complex Medium with Corn Dregs

以黑曲霉带渣发酵生产柠檬酸的培养过程为对象,探讨了用电容法在线活细胞量传感器测量复合培养基中可结团丝状菌的活细胞量的可能性。通过实验确定了仪器的最佳分析条件:低通滤波值为60,测定频率为双频(580,10 085 kHz)。实验结果表明,电容法活细胞量传感器的电容值与活细胞量之间有着较好的线性对应关系,其线性相关系数为0.994。在发酵培养液采用带渣发酵的情况下,考察了在线活细胞电容值与常规的离线测定菌浓方法,如细胞干重、波长600nm处吸光度OD600和菌体离心体积之间的关系结果表明,在0～20 h,各离线参数与电容值之间的线性相关系数最好的仅为0.91。同时利用在线活细胞传感器的电容值能较好地估计出比生长速率,比通过在线间接参数OUR、CER估计更准确。因此,电容传感器为黑曲酶带渣发酵提供了一个可靠的工具。

In this paper,cultivations of Aspergillus niger grown on an complex medium with corn dregs were performed.The feasibility of measuring online capacitance viable-cell mass of Fila-fungus grown on a complex medium was discussed.This study confirmed that the best measurement conditions were doubled frequency of 580 kHZ,10085 kHZ and low pass filter of 60.The result proved the relationship between capacitance and viable-cell mass with a correlation coefficient（R2） of 0.993 8.While complex medium with corn dregs was adopted,conventional off-line biomass determinations of several parameters,including DCW,optical density at 600nm wavelength（OD600）,packed mycelial volume（PMV） were performed throughout the bioprocess and then compared with on-line viable-cell concentrations measured using a capacitance probe.As a result,the best correlation coefficient（R2） is 0.907 2.During the same time frame,we compared the results determined by on-line indirect estimation methods including oxygen uptake rate（OUR） and carbon dioxide evolution rate（CER）,and reached at the conclusion that the specific growth rates estimated by on-line capacitance measurement could be more reliable during citric acid fermentation.Therefore,it is concluded that a capacitance probe is a practical tool for real-time viable biomass monitoring in a complex medium with corn dregs.