Improved ethanol productivity from lignocellulosic hydrolysates by <italic>Escherichia coli</italic> with regulated glucose utilization.

Background: Lignocellulosic ethanol could offer a sustainable source to meet the increasing worldwide demand for fuel. However, efficient and simultaneous metabolism of all types of sugars in lignocellulosic hydrolysates by ethanol-producing strains is still a challenge. Results: An engineered strain <italic>Escherichia coli</italic> B0013-2021HPA with regulated glucose utilization, which could use all monosaccharides in lignocellulosic hydrolysates except glucose for cell growth and glucose for ethanol production, was constructed. In <italic>E. coli</italic> B0013-2021HPA, <italic>pta</italic>-<italic>ackA</italic>, <italic>ldhA</italic> and <italic>pflB</italic> were deleted to block the formation of acetate, lactate and formate and additional three mutations at <italic>glk</italic>, <italic>ptsG</italic> and <italic>manZ</italic> generated to block the glucose uptake and catabolism, followed by the replacement of the wild-type <italic>frdA</italic> locus with the <italic>ptsG</italic> expression cassette under the control of the temperature-inducible λ pR and pL promoters, and the final introduction of pEtac-PA carrying <italic>Zymomonas mobilis pdc</italic> and <italic>adhB</italic> for the ethanol pathway. B0013-2021HPA was able to utilize almost all xylose, galactose and arabinose but not glucose for cell propagation at 34 °C and converted all sugars to ethanol at 42 °C under oxygen-limited fermentation conditions. Conclusions: Engineered <italic>E. coli</italic> strain with regulated glucose utilization showed efficient metabolism of mixed sugars in lignocellulosic hydrolysates and thus higher productivity of ethanol production. [ABSTRACT FROM AUTHOR]