In many ecosystems, microorganisms shield themselves in biofilms, restricting access of bacterial viruses (bacteriophages) to their bacterial hosts. Goal of our project is to analyze bacteriophages and their glycan-depolymerases in glycan-dominated biofilms and their impact on viral infection dynamics in biofilms. Using bacteriophages that infect plant pathogens of the genus Erwinia as model system, we will employ fluorescence correlation spectroscopy (FCS) to study phage mobility and infection rate. We will include this data into theoretical models of population dynamics, with special emphasis on biofilm-dissipating depolymerases and their synergies in phage mixtures. As a prerequisite, we will develop an algorithm for depolymerase annotation from viral genomes, also to screen metagenomes for new viral depolymerases, in order to gain a deeper understanding of phage-host relationships in biofilms. The discovery of new biofilm depolymerases is highly desirable for biotechnology as antimicrobial agents active against biofilm-forming pathogens.