Fig. 6

High-level melatonin production in a fermenter. a Fed-batch fermentation of EcMEL8. The cultures were added 0.1% L-arabinose at 18 h. The red arrow indicates the time (23 h) at which tryptophan, methionine, and 3% glycerol were added to the fermenter. The NAS and melatonin concentrations were measured at 29 h, 35 h, 47 h, 59 h, 71 h, and 83 h. b Fed-batch fermentation of EcMEL8 after optimization. Those were induced at 24 h with 0.1% l-arabinose. Tryptophan, methionine, and 3% glycerol were added to the fermenter at 36 h. The NAS and melatonin concentrations were measured at 60 h, 84 h, 108 h, 132 h, 156 h, and 180 h. (n = 2)