Premium
Modified Escherichia coli B (BL21), a superior producer of plasmid DNA compared with Escherichia coli K (DH5α)
Author(s) -
Phue JeNie,
Lee Sang Jun,
Trinh Loc,
Shiloach Joseph
Publication year - 2008
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21973
Subject(s) - escherichia coli , plasmid , recombinant dna , strain (injury) , biology , enterobacteriaceae , bacteria , microbiology and biotechnology , dna , chemistry , biochemistry , gene , genetics , anatomy
Plasmid DNA (pDNA) is an emerging experimental vaccine, produced in E. coli , initially targeted for viral diseases. Unlike traditional protein vaccines whose average dose is micrograms, the average dose of pDNA is on the scale of milligrams. Production yields are, therefore, important for the future development of this vaccine. The E. coli strains currently used for pDNA production, JM109 and DH5α, are both suitable for production of stable pDNA due to the deletion of recA and endA , however, these two E. coli K strains are sensitive to growth conditions such as high glucose concentration. On the other hand E. coli BL21 is less sensitive to growth conditions than E. coli JM109 or DH5α, this strain grows to higher densities and due to its active glyoxylate shunt and anaplerotic pathways is not sensitive to high glucose concentration. This strain is used for recombinant protein production but not for pDNA production because of its inability to produce stable pDNA. To adapt E. coli BL21 for stable pDNA production, the strain was mutated by deleting both recA and endA , and a proper growth and production strategy was developed. Production values, reaching 2 g/L were obtained using glucose as a carbon source. The produced plasmid, which was constructed for HIV clinical study, was found to have identical properties to the plasmid currently produced by E. coli DH5α. Biotechnol. Bioeng. 2008;101: 831–836. © 2008 Wiley Periodicals, Inc.