Research

Industrial-scale production and purification of a heterologous protein in Lactococcus lactis using the nisin-controlled gene expression system NICE: The case of lysostaphin

Igor Mierau¹ , Peter Leij¹ , Iris van Swam¹ , Barry Blommestein¹ , Esther Floris¹ , James Mond² and Eddy J Smid¹

¹  NIZO food research, P.O. Box 20, 6710 BA Ede, The Netherlands

²  Biosynexus, Inc., 9119 Gaither Road, Gaithersburg, MD 20877, USA

author email corresponding author email

Microbial Cell Factories 2005, 4:15doi:10.1186/1475-2859-4-15

Published:	27 May 2005

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.

Conclusion

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.