氮源对L-苏氨酸发酵的影响

以L-苏氨酸生产菌TRFC为供试菌株，研究了氮源对L-苏氨酸发酵的产量和糖酸转化率的影响。首先通过摇瓶实验确定发酵的最佳无机氮源和有机氮源分别为硫酸铵和酵母粉，进一步利用10L罐补料分批发酵确定硫酸铵和酵母粉的最佳用量，继续优化培养条件，采用发酵中后期流加硫酸铵和糖氨混合补料等措施，L-苏氨酸产量得到进一步的提高。在最优发酵条件下，通过10L罐补料分批发酵36h，产酸可达118.9g/L，糖酸转化率为47.6%。

THE EFFECT OF NITROGEN SOURCE ON L-THREONINE FERMENTATION

The effects of nitrogen sources on the production of L-threonine and conversion rate of glucose were studied with L-threonine production strain TRFC. The effects of different nitrogen sources on L-threonine yield and cell mass were evaluated on shake-flask scale. The results showed that ammonium sulfate and yeast extract was the optimal inorganic and organic source, respectively. High L-threonine yield was obtained when 2.0g/L yeast extract and 10g/L Ammonium sulfate were added to fermentation medium. L-threonine production was further increased by continuous feeding of 50% ammonium sulfate during metaphase and by feeding of glucose and ammonia mixture. Under these optimal conditions, the L-threonine production of 118.9g/L was achieved, and the conversion rate of glucose was 47.6%.