In this project, we aim to use a combination of bio-informatic and experimental approaches to explore important aspects of niche flexibility and functions of Lactobacillus strains, using the Lactobacillus casei/rhamnosus group as case study. Here, niche-adaptation of these bacteria will be explored for rather unexplored niches, namely fermented vegetables (carrots), the human vagina and the human respiratory tract, starting from isolates, which are in- house available through previous projects. Experiments will include niche-swap experiments, experimental evolution and functional analyses by constructed knock-out mutants. Special attention in this PhD project will be directed towards the role of adhesion in niche colonization. In previous research, a new type of fimbriae was found in L. casei and this will be further explored and molecularly characterized in this PhD project.