title: Industrial-scale production and purification of a heterologous protein in Lactococcus lactis using the nisin-controlled gene expression system NICE: the case of lysostaphin.
abstract: BACKGROUND
  The NIsin-Controlled gene Expression system NICE of Lactococcus lactis is one of the most widespread used expression systems of Gram-positive bacteria. It is used in more than 100 laboratories for laboratory-scale gene expression experiments. However, L. lactis is also a micro-organism with a large biotechnological potential. Therefore, the aim of this study was to test whether protein production in L. lactis using the NICE system can also effectively be performed at the industrial-scale of fermentation.
  
  
  RESULTS
  Lysostaphin, an antibacterial protein (mainly against Staphylococcus aureus) from S. simulans biovar. Staphylolyticus, was used as a model system. Food-grade lysostaphin expression constructs in L. lactis were grown at 1L-, 300-L and 3000-L scale and induced with nisin for lysostaphin production. The induction process was equally effective at all scales and yields of about 100 mg/L were obtained. Up-scaling was easy and required no specific effort. Furthermore, we describe a simple and effective way of downstream processing to obtain a highly purified lysostaphin, which has been used for clinical phase I trials.
  
  
  CONCLUSIONS
  This is the first example that shows that nisin-regulated gene expression in L. lactis can be used at industrial scale to produce large amounts of a target protein, such as lysostaphin. Downstream processing was simple and in a few steps produced a highly purified and active enzyme.
authors.affiliation: NIZO food research, P.O. Box 20, 6710 BA Ede, The Netherlands. igor.mierau@nizo.nl
authors.forename: Igor
authors.initials: I
authors.lastname: Mierau
authors.forename: Peter
authors.initials: P
authors.lastname: Leij
authors.forename: Iris
authors.initials: I
authors.lastname: van Swam
authors.forename: Barry
authors.initials: B
authors.lastname: Blommestein
authors.forename: Esther
authors.initials: E
authors.lastname: Floris
authors.forename: James
authors.initials: J
authors.lastname: Mond
authors.forename: Eddy J
authors.initials: EJ
authors.lastname: Smid