title: A food-grade system for inducible gene expression in Lactobacillus plantarum using an alanine racemase-encoding selection marker.
abstract: Food-grade gene expression systems for lactic acid bacteria are useful for applications in the food industry. We describe a new food-grade host/vector system for Lactobacillus plantarum based on pSIP expression vectors and the use of the homologous alanine racemase gene (alr) as selection marker. A new series of expression vectors were constructed by exchanging the erythromycin resistance gene (erm) in pSIP vectors by the L. plantarum WCFS1 alr gene. The vectors were applied for the overexpression of β-galactosidase genes from L. reuteri L103 and L. plantarum WCFS1 in an alr deletion mutant of L. plantarum WCFS1. The expression levels obtained in this way, i.e. without the use of antibiotics, were comparable to the levels obtained with the conventional system based on selection for erythromycin resistance. The new system is suitable for the production of ingredients and additives for the food industry.
authors.affiliation: Department of Food Sciences and Technology, University of Natural Resources and Life Sciences, Vienna, Austria.
authors.forename: Tien-Thanh
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Geir
authors.initials: G
authors.lastname: Mathiesen
authors.forename: Lasse
authors.initials: L
authors.lastname: Fredriksen
authors.forename: Roman
authors.initials: R
authors.lastname: Kittl
authors.forename: Thu-Ha
authors.initials: TH
authors.lastname: Nguyen
authors.forename: Vincent G H
authors.initials: VG
authors.lastname: Eijsink
authors.forename: Dietmar
authors.initials: D
authors.lastname: Haltrich
authors.forename: Clemens K
authors.initials: CK
authors.lastname: Peterbauer
mesh_terms: D000411:Alanine Racemase / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D004917:Erythromycin; D019649:Food Industry; D015870:Gene Expression; D005822:Genetic Vectors; D048191:Lactiplantibacillus plantarum / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D004917:Erythromycin; D001616:beta-Galactosidase; D000411:Alanine Racemase