探究磷酸盐浓度对大肠杆菌E.coli TRFP发酵生产L-异亮氨酸的影响。利用30 L发酵罐进行分批补料发酵试验,考察磷酸盐浓度对E.coli TRFP发酵生产L-异亮氨酸过程中生物量、比生长速率、L-异亮氨酸产量、发酵液中乙酸及NH4+浓度变化。结果表明,发酵初期维持低浓度磷酸盐(2 g/L KH2PO4),后期补加2 g/LKH2PO4可有效减缓菌体衰退,最终使菌体生物量和异亮氨酸产量分别提高了24.5%和12.7%,且副产物乙酸含量明显降低。

The effects of phosphate on the fermentation of L-isoleucine was studied with L-isoleucine producing strain E.coli TRFC.The effects of initial phosphate concentration in the fermentation process on biomass,the specific growth rate,yield of L-isoleucine,concentration of byproduct acetic acid and ammonium were studied by carrying out fed-batch fermentation of E.coli TRFC in 30-Liter fermentor.The results showed that maintaining the initial phosphate at the concentration of 2g/L and adding 2g/L phosphate into the broth in the late period of fermentation could effectively slow down bacterial recession.The biomass and production of L-isoleucine increased by 24.5% and 12.7%,while the amount of by-product acetic acid decreased significantly.