chitin is a typical component of the exoskeleton of shellfish. It has been reported that Pseudoalteromonas strains can produce chitinases, implying that they have the ability to degrade chitin, respectively. Whole genome sequencing of multiple species in Pseudoalteromonas have been carried out in our group. In this thesis, we performed a research on the utilization of alginate and chitin by different species in this genus by using comparative genomic analyses and experimental verification.