초록
<P><B>Abstract</B></P> <P> <I>Corynebacterium glutamicum</I> is known to produce organic acids under anaerobic culture conditions, in particular, lactic, succinic, and acetic acids. Our study is focused on acetic and succinic acid production using a lactate dehydrogenase-deficient strain of <I>C. glutamicum</I>. Usually, with this bacterium, the organic acid production process is based on an initial aerobic growth phase, followed by a rapid deoxygenation and an anaerobic production phase. In our study, we demonstrated that this strategy was unfavorable for the production of organic acids. Conversely, we showed that applying the best transition strategy based on progressive deoxygenation significantly increased the concentration of organic acids up to 640%. This was observed either by applying controlled dissolved oxygen concentrations or by decreasing the steps of gas flow rates. Our results also showed that applying constant oxygen transfer flux throughout the culture, and thus in the absence of the anaerobic phase, promoted constant production yields (approximately 0.5mol of succinate or acetate per mole of glucose). In this case, acetate production (120mM) was favored over succinate production (132mM), resulting in a decrease in the molar ratio of products (succinate/acetate) from 4.8 to 1.1 between progressive deoxygenation and constant OTR cultures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A rapid deoxygenation disadvantages organic acids production using <I>C. glutamicum</I>. </LI> <LI> Succinate production is multiplied by a factor 7.4, changing deoxygenation strategy. </LI> <LI> Microaerobiosis favored acetate production at the expense of succinate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>