Fig. 7.

Bioconversion for NAG by engineered strain 0419. a Scale-up bioconversion of NAG production in a 1-L fermenter. The black square indicates the concentration of NAG. The hollow circle represents the concentration of glutamate. The black circle represents the concentration of glucose consumed. b Substrate inhibition. The concentrations of glutamate used were: 1: 50 mM; 2: 100 mM; 3: 200 mM; 4: 500 mM; 5: 1 M. The glucose concentration was 50 mM. The reaction was carried out for 2 h. c Product inhibition. The concentration of NAG at 0 h represented the initially added concentration. In detail, the concentrations of NAG added initially were: 1: 0 mM; 2: 20 mM; 3: 40 mM; 4: 70 mM; 5: 100 mM. The bioconversion reactions were performed at 37 °C and 200 rpm for 2 h