Improved glucosamine and N-acetylglucosamine production by an engineered Escherichia coli via step-wise regulation of dissolved oxygen level.

Influence of dissolved oxygen (DO) levels (10%, 20%, 30% and 40%) on the glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) production by recombinant Escherichia coli was investigated. It was found that the highest specific GlcN and GlcNAc production rates were obtained at different DO levels at different culture stages. Namely, the highest specific GlcN and GlcNAc production rates were obtained at 20% during 0-2h, 30% during 2-8h, 40% during 8-12h, and 30% during 12-18h. Accordingly, a step-wise DO control strategy was proposed, namely DO was controlled at 20% during 0-2h, 30% during 2-8h, 40% during 8-12h and 30% during 12-18h. With this DO control approach, the total production of GlcN and GlcNAc reached 72.89gL(-1), which was 1.37 times that without DO control (53.31gL(-1)). The developed step-wise DO control strategy may be useful for the industrial GlcN and GlcNAc production by recombinant E. coli.