The main objective of the thesis is to develop L. plantarum as a whole-cell biocatalyst towards the production of prebiotic oligosaccharides. We investigated functionality of anchor motifs (lipoprotein Lp_1261 and cell wall anchor cwa2) for the display of heterologous proteins (beta-mannanase and chitosanase) on the Lactobacillus cell surface. Due to the limitations of the inducible expression system in the food-related applications, the constitutive promoters (Pgm and SlpA from L. acidophilus NCFM and L. acidophilus ATCC4356, respectively) were investigated for constitutive expression and display of [beta]-mannanase on the Lactobacillus cell surface. Our study indicated that the promoter slpA is well-suitable for constitutive production and surface display of heterologous proteins in L. plantarum, providing an alternative for the strong inducible promoter-based anchoring vectors. In the second part of this thesis, the production of beta-galactosidases, known as important enzymes in dairy industry, was studied for the formation of galacto-oligosaccharides (GOS). [beta]-galactosidase from L. reuteri was successfully overexpressed in Lactobacillus hosts using the pSip expression vectors. To further explore the potential of the pSip system, the effects of various cultivation and induction conditions on gene expression were investigated. [beta]-Galactosidase from Streptococcus thermophilus overexpressed in L. plantarum WCFS1 was also examined for the valorization of whey, a significant waste from the dairy industry, for the production of galacto-oligosaccharides (GOS).