dehydrogenase(GDH)and glutamate synthase((}GAT)were investigated in glutamine production by
fermentation of Cor几、mebacteriunr爪utarrricurrr NS611 after 3 h of in-situ nitrogen starvation. It was shown that
the strain in the later growth phase entered naturally into in-situ nitrogen starvation by controlling the initial
concentration of urea and the biomass was slightly decreased. The pH value reached 6.5 again in the culture
system, which confirmed the beginning of nitrogen starvation in the culture system. After 3 h nitrogen starvation
the activity of GS was increased over two folds and the time of high activity of GS persisted three folds longer in
the gradient fed nitrogen system than that in the normal fed batch. The higher activity of GDH was also
maintained. The glutamine production increased by 72%than the original technology of nitrogen starvation and
the time of fermentation was shortened by above 12 h.
Keywords
nitrogen ,
Coryoebacteri a nr刁utanricum NS611，glutamine, in-situ nitrogen starvation, gradient fed
glutamine synthetase
