Altering the sigma D factor of RNA polymerase and thereby improving the tolerance of E. coli strains to isobutanol.

Metabolic engineering optimizes the synthetic pathways of microbial cell factories, including modifying relevant metabolic pathways, eliminating enzymes related to metabolic shunts, and balancing ATP in metabolic pathways, thereby driving metabolic flux to the production of target products. However, stress conditions often occur during the fermentation process, such as organic solvent stress. High concentrations of organic solvents will destroy the cytoskeleton, destroy the cell membrane structure, significantly reduce the absorption of nutrients, and hinder the synthesis of biological macromolecules. Escherichia coli is the main host strain for the production of higher alcohols. Generally, 8.0 g/L isobutanol will cause stress to it, seriously hindering the synthesis potential of the strain. We found that overexpressing some sigma factor mutants of RNA polymerase can improve the tolerance of strains to isobutanol, and uncovered potential key genes after sequencing their transcriptomes.