This paper is concerned with estimation and control of the yield in the process of clarifying fermentation broths for the production of cephalosporin C by ceramic membrane.Three parameters (volume concentration ratio in pre-concentration step

a; volume dilution ratio in diafiltration step

b; volume concentration ratio in post-concentration step

c) are introduced in the model to estimate the yield of cephalosporin C.The equations for estimating overall yield and the piecewise functions for estimating real-time yield are put forward.The yields are compared with the operation modes of continuous feed diafiltration (CFD) and intermittent feed diafiltration (IFD) by model calculation and experiment.The results show that the model is helpful for optimizing the microfiltration process by enhancing the yield and reducing the overall operation time.By using the model in this paper

the yield of cephalosporin C can be controlled effectively in the process of membrane filtration.