Effect of reducing agents in an aerobic amino acid fermentation

This study focuses on the effects of the reducing agents, dithiothreitol (DTT) and glutathione (GSH), on amino acid production in aerobically growing Corynebacterium glutamicum . The problem of reducing agent addition affecting the dissolved oxygen level was solved by positioning the culture at a high dissolved oxygen level and feeding the reducing agent into the fermentor. We show that it is possible to lower the redox potential even in a highly aerobic environment. The addition of DTT to the fermentation during the growth phase caused a significant increase in specific amino acid production rate and total amino acids produced, as compared with a control. In contrast, GSH had an inhibitory effect. © 1992 John Wiley & Sons, Inc.