Fig 13. Effect of the addition of different substrates on the accumulation of each intermediate and product.

The highest values of the products per g dry cell weight and per hour were calculated by Eq (2).

$$\text{v}=\frac{\mathrm{\Delta }\text{C}}{\mathrm{\Delta }\text{t}\times \text{X}}$$ (2)

where v is the highest value (μmol/g h) of each intermediate or product, △C is the amount of accumulated amount (μmol/L) of the products during the bioconversion, △t is the bioconversion time (h) corresponding to the highest value of each intermediate or product, and X is the amount of cells in dry cell weight (g/L). The amount of the added substrates were 111111.11 μmol/L (Glu), 13000.00 μmol/L (Leu), 7000.00 μmol/L (Phe), 5000.00 μmol/L (Tyr), 1500.00 μmol/L (Ca), and 1000.00 μmol/L (pC) respectively. The bioconversion medium contained 833.33 μmol/L glucose. Values in each figure are the mean of three replications and shown with standard deviation. Different letters in the figure indicate the data were significantly different at the level of p<0.01 in Tukey test.