Objective To optimize the clarifying filtration procedure for Clostridium botulinum culture.Methods Cl.botulinum type A culture was subjected to clarifying filtrations of grades 1 and 2 by combination of various types of filters,based on which the optimal combination was screened.The Cl.botulinum types A,B,E and F in scale-up culture was subjected to clarifying filtration by the optimal combination.Results The combination of P700K + 50P used for clarifying filtrations of grades 1 and 2 of Cl.butulinum type ...