Process analysis of l-lysine fermentation with Corynebacterium glutamicum under different oxygen and carbon dioxide supplies and redox potentials

Abstract

The production of l-lysine by a homoserine and leucine requiring strain of Corynebacterium glutamicum ATCC 21513 was studied. O 2 limitation caused a decrease in both substrate consumption rate and the conversion efficiency of substrate to l-lysine, concomitant with formation of l-lactate and isobutyric acid. The maximum conversion rate into l-lysine was obtained at 30–35% dissolved oxygen saturation and at a redox potential up to −140 mV. Increased CO 2 levels increased biomass yield and considerably decreased formation of organic acids. Under optimal oxygen conditions, without CO 2 addition, a decrease of 33% in isobutyric acid and 26% in lactate production and an ncrease of 20% in l-lysine production were obtained compared with cultures grown under 15–20% of O 2 saturation.