title: Production of the short peptide surfactant DAMP4 from glucose or sucrose in high cell density cultures of Escherichia coli BL21(DE3).
abstract: BACKGROUND
  Peptides are increasingly used in industry as highly functional materials. Bacterial production of recombinant peptides has the potential to provide large amounts of renewable and low cost peptides, however, achieving high product titers from Chemically Defined Media (CDM) supplemented with simple sugars remains challenging.
  
  
  RESULTS
  In this work, the short peptide surfactant, DAMP4, was used as a model peptide to investigate production in Escherichia coli BL21(DE3), a classical strain used for protein production. Under the same fermentation conditions, switching production of DAMP4 from rich complex media to CDM resulted in a reduction in yield that could be attributed to the reduction in final cell density more so than a significant reduction in specific productivity. To maximize product titer, cell density at induction was maximized using a fed-batch approach. In fed-batch DAMP4 product titer increased 9-fold compared to batch, while maintaining 60% specific productivity. Under the fed-batch conditions, the final product titer of DAMP4 reached more than 7 g/L which is the highest titer of DAMP4 reported to date. To investigate production from sucrose, sucrose metabolism was engineered into BL21(DE3) using a simple plasmid approach. Using this strain, growth and DAMP4 production characteristics obtained from CDM supplemented with sucrose were similar to those obtained when culturing the parent strain on CDM supplemented with glucose.
  
  
  CONCLUSIONS
  Production of a model peptide was increased to several grams per liter using a CDM medium with either glucose or sucrose feedstock. It is hoped that this work will contribute cost reduction for production of designer peptide surfactants to facilitate their commercial application.
authors.forename: Michele
authors.initials: M
authors.lastname: Bruschi
authors.affiliation: Centre for Microbial Electrosynthesis (CEMES), Advanced Water Management Centre (AWMC), Research Road (Bldg 60), The University of Queensland, St, Lucia 4072, QLD, Australia. j.kromer@uq.edu.au.
authors.forename: Jens O
authors.initials: JO
authors.lastname: Krömer
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Steen
authors.forename: Lars K
authors.initials: LK
authors.lastname: Nielsen
mesh_terms: D000595:Amino Acid Sequence; D061249:Batch Cell Culture Techniques; D019149:Bioreactors / Q000382:microbiology; D003470:Culture Media; D004926:Escherichia coli / Q000166:cytology* / Q000254:growth & development* / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D055442:Metabolome; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism*; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D003470:Culture Media; D010455:Peptides; D011994:Recombinant Proteins; D013501:Surface-Active Agents; D013395:Sucrose; D005947:Glucose