Polyhydroxyalkanoates (PHAs) are biopolyesters produced by bacteria as intracellular granules under metabolic stress conditions. Many carbon sources such as alkanes, alkenes, alcohols, sugars, fatty acids can be used as feedstock and thus a wide variety of polyesters and monomer units can be potentially synthetized. The work presented here describes the process to chemically modify such biopolymers in order to render them readily available for the preparation of bio-molecular conjugates as promising new classes of biocompatible biomaterials. Such hybrid biomaterials belong to the rapidly growing class of biocompatible polymers, which are of great interest for medical and therapeutic applications. In this work, the biosynthesis of a new PHA homopolymer and the chemical modification, an epoxidation reaction, are described.