The present invention in various aspects and embodiments provides engineered bacterial strains having a modified genome that provides advantages in maintenance and biosynthetic processes when cultured at large scale. The present invention further provides methods for large-scale fermentation using the bacterial strains. In various embodiments, the strain engineering yields a reduction in cellular responses to micro-environmental stimuli imposed in large scale bioreactors.

This invention provides a recombinant Escherichia coli (E. coli) host cell for producing a Klebsiella pneumoniae (K. pneumoniae) O-antigen, wherein the E. coli host cell comprises a polynucleotide encoding the K. pneumoniae O-antigen, including methods of producing and purifying the K. pneumoniae O-antigen.