Electrochemical studies on fermentation. I. Application of electro-energizing method to L-glutamic acid fermentation.

Abstract

An electro-energizing fermentation (E-E F) method has been developed. In this method, a direct electrical current is applied to a microbial culture to accelerate the reductive metabolism of microorganisms or to impart profitable effects to microbial cells. This E-E F method was applied to L-glutamic acid fermentation by Brevibacteriurn fiavum No. 2247. When glucose was used as a substrate, the addition of 0.01 mi s neutral red (NR), redox dye (electron carrier), to the fermentation broth at the beginning of cultivation was effective for L-glutamate (L-Glu) production. A direct current of 200_??_300 μA/cmz at 1.5 V was applied through out the cul-tivation of this bacterium. This resulted in about a 10% increase in yield of L-Glu.