The broad host range vector pBBR1MCS-2 has been evaluated as an expression vector for Zymomonas mobilis. The transformation efficiency of this vector was 2 Ã— 103 CFU per 'g of DNA in a recombinant strain of Z. mobilis ZM4/AcR containing the plasmid pZB5. Stable replication for this expression vector was demonstrated for 50 generations. This vector was used to study xylose metabolism in acetate resistant Z. mobilis ZM4/AcR (pZB5) by over-expression of xylulokinase (XK), as previous studies had suggested that XK could be the rate-limiting enzyme for such strains. Based on the above vector, a recombinant plasmid pJX1 harboring xylB (expressing XK) under control of a native Z. mobilis promotor Ppdc was constructed. When this plasmid was introduced into ZM4/AcR (pZB5) a 3-fold higher XK expression was found compared to the control strain. However, fermentation studies with ZM4/AcR (pZB5, pJX1) on xylose medium did not result in any increase in rate of growth or xylose metabolism, suggesting that XK expression was not rate-limiting for ZM4/AcR (pZB5) and related strains.
Jeon, Y. J., Svenson, C. J., & Rogers, P. L. (2005). Over-expression of xylulokinase in a xylose-metabolising recombinant strain of Zymomonas mobilis. FEMS Microbiology Letters, 244(1), 85-92. https://doi.org/10.1016/j.femsle.2005.01.025