用Maxwell-Wagner分布实时在线检测啤酒酵母浓度

On-line and In-situ Measuring Concentrations of Beer Yeast based on maxwell-Wagner Dispersion

酵母的存在会改变发酵液的电特性，发酵液在无线电频率范围内的电特性可用电容率和电导率充分地描述。实验证实发酵液在无线电频率范围内的电容率增量是测量频率和生物量浓度的函数。基于对发酵液电容率分布的研究，本文提出了测量酵母浓度的新方法。用本方法不用取样就能对发酵液中的酵母浓度进行实时在线测量，而且测得的是活的酵母浓度。

This paper concerns a device and a method which monitor yeast concentrations on-line andin-situ, in a fermentation process. The Presence of microbial cells would affect the dielectrical properties ofmicrobial suspensions. At radio-frequencies, the intrinsic passive electrical properties of cell suspensions arecompletely specified by its conductivity and permittivity. At radio-frequencies the dielectric permittivity of cellsuspensions are monotonic function of the measuring frequency and cell density. Based on this understanding anew method for measuring biomass concentration is proposed. Using this method the biomass concentrations aremeasured on-line and in-situ without taking samples from the bioreactor, and only viable cells are detected.