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Background: Lactobacillus, which has great adhesion ability to intestinal mucosa and is able to hydrolyse plant cell walls, can be used more efficiently as a feed additive. To increase the adhesion ability and display a fungal xylanase on the cell surface of Lactobacillus casei, the Listeria monocytogenes cell-wall-anchoring protein gene, mub, was introduced into L. casei ATCC 393 cells and used as a fusion partner to display the rumen fungal xylanase XynCDBFV on the cell surface of the transformed strains., Results: The transformed strain L. casei pNZ-mub, which harboured mub gene, displayed recombinant Mub on its cell surface and showed greater adhesion ability to Caco-2 cells than the parental strain. The transformed strain L. casei pNZ-mub/xyn, which harboured mub-xynCDBFV fusion gene, acquired the capacity to break down oat spelt xylan and exhibited greater competition ability against the adhesion of L. monocytogenes to Caco-2 cells, in comparison with the parental strain., Conclusion: Mub has a potential to be used as a fusion partner to display heterologous proteins on the cell surface of Lactobacillus. Moreover, this is the first report of the successful display of xylanase on the cell surface of Lactobacillus., (© 2013 Society of Chemical Industry.)

The collagen-binding protein gene cnb was cloned from the probiotic Lactobacillus reuteri strain Pg4. The DNA sequence of the cnb gene (792 bp) has an open reading frame encoding 263 amino acids with a calculated molecular weight of 28.5 kDa. The cnb gene was constructed so as to constitutively express under the control of the Lactococcus lactis lacA promoter and was transformed into Lactobacillus casei ATCC 393, a strain isolated from dairy products with poor ability to adhere to intestinal epithelial cells. Confocal immunofluorescence microscopic and flow cytometric analysis of the transformed strain Lb. casei pNZ-cnb indicated that Cnb was displayed on its cell surface. Lb. casei pNZ-cnb not only showed a higher ability to adhere to Caco-2 cells but also exhibited a higher competition ability against Escherichia coli O157:H7 and Listeria monocytogenes adhesion to Caco-2 cells than Lb. casei ATCC 393.