title: Self-cycling operation increases productivity of recombinant protein in Escherichia coli.
abstract: Self-cycling fermentation (SCF), a cyclical, semi-continuous process that induces cell synchrony, was incorporated into a recombinant protein production scheme. Escherichia coli CY15050, a lac(-) mutant lysogenized with temperature-sensitive phage λ modified to over-express β-galactosidase, was used as a model system. The production scheme was divided into two de-coupled stages. The host cells were cultured under SCF operation in the first stage before being brought to a second stage where protein production was induced. In the first stage, the host strain demonstrated a stable cycling pattern immediately following the first cycle. This reproducible pattern was maintained over the course of the experiments and a significant degree of cell synchrony was obtained. By growing cells using SCF, productivity increased 50% and production time decreased by 40% compared to a batch culture under similar conditions. In addition, synchronized cultures induced from the end of a SCF cycle displayed shorter lysis times and a more complete culture-wide lysis than unsynchronized cultures. Finally, protein synthesis was influenced by the time at which the lytic phase was induced in the cell life cycle. For example, induction of a synchronized culture immediately prior to cell division resulted in the maximum protein productivity, suggesting protein production can be optimized with respect to the cell life cycle using SCF.
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada.
authors.forename: Zachary J
authors.initials: ZJ
authors.lastname: Storms
authors.forename: Tobin
authors.initials: T
authors.lastname: Brown
authors.forename: Dominic
authors.initials: D
authors.lastname: Sauvageau
authors.forename: David G
authors.initials: DG
authors.lastname: Cooper
mesh_terms: D001435:Bacteriophages / Q000235:genetics; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods; D018929:Cell Culture Techniques / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000821:virology; D005285:Fermentation; D008242:Lysogeny; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D001616:beta-Galactosidase