JP2008263945A5 - - Google Patents

Claims (6)

  The fermentation broth of E. coli having the ability to produce lactic acid is filtered through a separation membrane, the product is recovered from the filtrate, and the unfiltered liquid is retained or refluxed in the fermentation broth, and the fermentation raw material for E. coli is used. A method for producing lactic acid by continuous fermentation added to the fermentation broth, wherein a porous membrane having pores with an average pore diameter of 0.01 μm or more and less than 1 μm is used as the separation membrane, and the difference between the membranes A method for producing lactic acid by continuous fermentation, wherein the filtration is carried out at a pressure of 0.1 to 20 kPa. ^2. The continuous fermentation according to claim 1, wherein the porous separation membrane has a pure water permeability coefficient of 2 × 10 ⁻⁹ m ³ / m ² / s / pa to 6 × 10 ⁻⁷ m ³ / m ² / s / pa. For producing lactic acid.   The method for producing lactic acid by continuous fermentation according to claim 1 or 2, wherein the porous membrane has an average pore size of 0.01 µm or more and less than 0.2 µm, and a standard deviation of the average pore size is 0.1 µm or less. The method for producing lactic acid by continuous fermentation according to any one of claims 1 to 3, wherein the membrane surface roughness of the porous membrane is 0.1 µm or less. The method for producing lactic acid by continuous fermentation according to any one of claims 1 to 4, wherein the porous membrane is a porous membrane comprising a porous resin layer. The method for producing lactic acid by continuous fermentation according to any one of claims 1 to 5, wherein the membrane material of the porous membrane is a polyvinylidene fluoride resin.