Data.docx

In this work, we first use glucose and glycerol as co-carbon source to improve 2′-FL production from 2.67 to 3.62 g/L. Then, the effect of the deletion of the genes arcA or iclR on 2′-FL production by E. coli FL-B21 was investigated. Knockout of arcA and iclR was surprisingly useful for avoiding acetate formation. Moreover, the arcA mutant FL-011 displayed higher 2′-FL production and higher lactose and glycerol utilization efficiency than the control strain FL-B21. The 2′-FL production of the arcA mutant FL-011 was 5.04 g/L. To maximize 2′-FL production by FL-011, systematic optimization of the culture medium composition and induction conditions was performed. As a result, the production of 2′-FL reached 7.1 g/L in shake-flask culture.