Table 2.

Fed-batch transformation experiment using different lysine feeding strategies

Feed strategy	l- lysine (g/L)	Hydroxylysine (g/L)	2-OH-PDA (g/L)	Molar yield (hydroxylysine/l-lysine) (%)
1	150.1 ± 3.6	63.4 ± 3.6	46.2 ± 1.3	38.1 ± 1.1
2	170.8 ± 5.2	75.3 ± 2.5	54.9 ± 2.6	39.9 ± 1.9
3	159.6 ± 4.1	110.5 ± 5.1	80.5 ± 2.9	62.6 ± 2.3

l-Lysine was fed using three different strategies. (1) First, 150 g/L lysine and 180 g/L α-ketoglutaric acid were added at the start of the reaction. (2) l-Lysine was initially added at 60 g/L and α-ketoglutaric acid at 72 g/L. When the concentration of l-lysine dropped to 30 g/L, 60 g/L l-lysine and 72 g/L α-ketoglutaric acid were added to the reaction mixture. (3) A feeding rate of 2 g/(L·h) l-lysine and 2.4 g/(L·h) α-ketoglutaric acid was maintained throughout the reaction