Fig. 6

Optimization of L-carnosine production by the engineered enzyme in the whole-cell reaction. A, Different temperature. B, Different reaction time. C, Different initial pH. D, Different ratio between β-AlaOMe and L-histidine. The left Y-axis represents titer and the right Y-axis represents the relative yield. The highest titer was set as 100%. The reactions were performed by the whole-cell with a final OD₆₀₀ = 20 in a buffer of 100 mM Na₂CO₃. The substrate concentrations were tentatively set at 10 mM β-AlaOMe and 50 mM L-histidine, except for the figure D, in which 10, 20, 30, 50 and 100 mM β-AlaOMe were respectively added with 50 mM L-histidine