Fig. 4

EcMEL1-7 strains catalyzed the production of NAS and melatonin and the effect of different concentrations of glycerol in conversion medium. a Production of NAS and melatonin by fermentation of the EcMEL1-7 strains for 96 h in shake flasks as described in method 2. b The production of NAS and melatonin by fermentation of EcMEL7 with different concentrations of glycerol. Data are the means ± standard deviations of triplicate experiments. The absence of error bars indicates that the error was smaller than the symbol size