Flexibility of the metabolism of Corynebacterium glutamicum 2262, a glutamic acid-producing bacterium, in response to temperature upshocks.

In order to test the temperature sensitivity of glutamate production metabolism, several temperature shifts, from 33 to 37, 38, 39, 40 or 41 degrees C, were applied to the temperature-sensitive strain, Corynebacterium glutamicum 2262, cultivated in a 24-h fed-batch process. Whereas glucose was entirely dedicated to biomass synthesis when cells were grown at 33 degrees C, applying temperature upshocks, whatever their range, triggered a redistribution of the carbon utilisation between glutamate, biomass and lactate production. Although increasing the culture temperature from 33 to 37, 38, 39 or 40 degrees C resulted in final glutamate titers superior to 80 g/l, temperatures resulting in the best chanelling of the carbon flow towards glutamic acid synthesis were 39 and 40 degrees C. Moreover, this study showed that the higher the temperature, the slower the growth rate and the higher the lactate accumulation.