초록
<P>The effects of different yeast extracts (YEs) and the growth-limiting factors (L-leucine) on the growth of<I>Escherichia coli</I>and the yield of L-tryptophan (Trp) were investigated in this study. YE A was most beneficial for the Trp production and DCW among five YEs. The maximum DCW was 0.646 g/L (36.6% higher than the control) when 0.4845 g/L Leu was supplemented in 100 ml media in a 500 ml flask, and the maximum yield of Trp was 0.0259 g/L, which was about 52.4% higher than the control (0.0170 g/L). Furthermore, the maximum DCW was up to 23.9 g/L (34.3% higher than the control) when 0.4845 g/L Leu was supplemented in a 10 L fermenter, and the maximum yield of Trp was 0.983 g/L, which was about 34.8% higher than the control (0.729 g/L). These results indicated that Leu was beneficial for the growth of<I>Escherichia coli</I>and the yield of Trp.</P>