Polyhydroxyalkanoates, including PHB, are storage polymers produced by various bacteria when the culture environment is not optimal for growth. During the past decade, polyhydroxyalkanoates have attracted commercial and academic interest as a source for renewable and biodegradable plastics (Lee 1996; Steinbuchel and Hein 2001). In addition, PHB granules have been used as support materials for protein chromatography and immobilization. For example, Moldes et al. (2004) used PHB granules for the immobilization of recombinant proteins via the fusion with a novel tag (BioF). The BioF consisted of an N-terminal functional domain of phasin enabling the target fusion protein to attach to PHB granules within the host cell. After separation of the PHB granules by mild centrifugation (4000g for 30 min), the BioF tag-fusion protein could be recovered by detergent treatment such as Triton X-100 or sarkosyl. However, many soluble proteins cannot withstand detergent solubilization. Banki et al. (2005) cleverly circumvented this problem by employing intein-mediated self-cleavage to recover the target protein. Importantly, intein cleavage occurs at mild conditions, reducing the risk of denaturation or covalent modification of the protein via processes such as deamidation, etc.