In this paper, we propose a semantic web based solution to implement the Interoperability Framework (IF) for Persistent Identifiers (PI) developed within the context of APARSEN EU project. The IF provides a comprehensive, semantics-aware solution for interoperability of heterogeneous Persistent Identifier systems. Such a solution aims to provide added-value services built on an Interoperability Knowledge Base. The IF ontology refinement and the related prototype specifics have been designed adopting a bottom-up approach that starts from a)the analysis of metadata provided by Content Providers and b)the collection of functional and semantic requirements of Persistent Identifier Domains (PID to fostering ontology-based metadata translation among different bodies. Conclusions and intended future work close the paper.