abstract |
To control the flow rate of a liquid culture medium in a membrane separation tank without affecting the culture conditions in a culture tank and to increase the production efficiency of a chemical by inhibiting the precipitation of a microorganism or culture cells, provided is a method for producing a chemical which comprises culturing a microorganism or culture cells in a culture tank, feeding the liquid culture medium from the culture tank to a membrane separation tank and filtering the same through a separation membrane, collecting a fermentation product as the chemical from the permeate and, at the same time, returning the unfiltered liquid culture medium not having been filtered in such a manner as combining the same with the liquid culture medium in the upstream side of the membrane separation tank, wherein a portion of the liquid culture medium fed from the culture tank is passed outside the membrane separation tank depending on the inflow side pressure of the membrane separation tank. |