Advanced Genomic Engineering Strategy based on Recombineering Protocols to “Tailor” Escherichia coli Strains

Abstract

A systematic approach based on bacteriophage Lambda (Lambda Red) and flippase-flippase recognition targets (FLP-FRT) recombinations was proposed for genomic engineering of Escherichia coli. For demonstration purposes, DNA operons containing heterologous genes (i.e. pac encoding E. coli penicillin acylase and palB2 encoding Pseudozyma antarctica lipase B mutant) engineered with regulatory elements, such as strong/inducible promoters (i.e. Ptrc and ParaB), operators, and ribosomal binding sites, were integrated into the E. coli genome at designated locations (i.e. lacZYA, dbpA, and lacI-mhpR loci) either as a gene replacement or gene insertion using various antibiotic selection markers (i.e. kanamycin and chloramphenicol) under various genetic backgrounds (i.e. HB101 and DH5α). The expression of the inserted foreign genes was subject to regulation using appropriate inducers [Isopropyl β-D-1-thiogalactopyranoside (IPTG) and arabinose] at tuneable concentrations. The developed approach has paved an effective way to “tailor” plasmid-free E. coli strains with desired genotypes suitable for various biotechnological applications, such as biomanufacturing and metabolic engineering.