Deletion of pyruvate decarboxylase gene in Zymomonas mobilis by recombineering through bacteriophage lambda red genes

Zymomonas mobilis ZM4 is a gram negative ethanologenic bacterium used in several biotechnological applications. Metabolic engineering in this bacterium is limited because of the available genome engineering tools. In the present study, we report genome engineering in this bacterium using bacteriophage lambda Red genes. Stability of plasmid replicons RK2 (pSIM9) and pBBR1 (pSIM7) containing the lambda Red genes was found to be 78% and 74%, respectively. We demonstrate successful deletion of pyruvate decarboxylase gene by recombineering in Z. mobilis. The deletion was confirmed by PCR and by estimating the metabolites formed. Ethanol, which was the main product in wild type cells, was formed in almost negligible amount in the pdc-deleted mutant. The developed Δpdc Z. mobilis cells can be exploited for production of desired bioproducts by expression of suitable enzymes that can regenerate NAD+.