pH及溶氧对重组大肠杆菌发酵生产5-氨基乙酰丙酸的影响

以重组大肠杆菌DALA为实验菌株，研究了该菌株在机械搅拌通风发酵罐发酵过程中pH以及溶解氧对5-氨基乙酰丙酸（ALA）积累的影响。结果发现，发酵前期（0～27 h）pH保持为6.5；稳定期后期（28～48 h），pH为6.0时有利于5-ALA的积累。其次，通过控制转速与通气量调节发酵液中的溶氧，发现发酵前期转速为500 r/min，通气量为2 vvm；稳定期后期，转速降低至250 r/min，通气量减少为1 vvm，有利于重组菌DALA发酵生产5-ALA，在此条件下发酵5-ALA的产量可达到3.46 g/L。

Effect of pH and dissolved oxygen on the fermentation production of 5-aminolevulinic acid by recombinant Escherichia coli

Using the recombinant Escherichia coli DALA as experimental strains, the effects of pH and dissolved oxygen on the 5-aminolevulinic acid (5-ALA) during fermentation in mechanical stirred fermentation tank were researched. The results showed that the pH was 6.5 in the early period of fermentation (0-27 h), and in the late period of stable stage (28-48 h), the pH was 6.5, which was conducive to the accumulation of 5-ALA. Besides, by controlling the rotate speed and the aeration to adjust dissolved oxygen in the fermentation liquid, it showed that in the early period of fermentation, the rotate speed was 500 r/min and aeration was 2 vvm. In the late period of stable stage, the rotate speed and aeration were reduced to 250 r/min and 1 vvm, respectively, which was conducive to the fermentation production of 5-ALA by recombinant E. coli. Under the conditions, the yield of 5-ALA was up to 3.46 g/L.