以L-色氨酸生产菌E.coli TRTH为供试菌株,研究了氮源对L-色氨酸发酵的影响。利用30 L发酵罐进行分批补料发酵试验,确定了最佳有机氮源和无机氮源分别为酵母粉和硫酸铵,进一步确定酵母粉和硫酸铵的最佳用量为1 g/L和10 g/L,最后采用NaOH和氨水混合补料控制发酵液中NH4+浓度在120 mmol/L以下,发酵38 h,菌体生物量和L-色氨酸产量分别达到53.42 g/L和32.6 g/L,实现了大肠杆菌的高密度培养。

The effects of nitrogen sources on the fermentation of L-tryptophan were studied with L-tryptophan producing strain E.coli TRTH.The results showed that yeast extract and ammonium sulfate was the optimal organic and inorganic source by carrying out fed-batch fermentation of E.coli TRTH in 30-Liter fermentor.High L-tryptophan yield was obtained when 1.0 g/L yeast extract and 10 g/L ammonium sulfate were added to fermentation medium.By controlling the concentration of NH4+ less than 120 mmol/L,the biomass and production of L-tryptophan achieved 53.42 g/L and 32.6 g/L,which accessed high cell density cultivation.