Cell Surface Display of Poly(3-hydroxybutyrate) Depolymerase and its Application

Abstract

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters, that accumulate intracellularly as a carbon and/ or energy source in numerous bacteria, to provide renewable resources under nutrient limited conditions. In PHAaccumulating bacteria, many enzymes, including PHA synthase, phasin, epimerase, oligomer hydrolase and depolymerase, play a role in the biosynthesis and degradation of PHAs [1][2][3][4]. Of those, PHA depolymerases have drawn much attention for their novel characteristics such as high stability, relatively small molecular weight (< 70 kDa), consisting of only one polypeptide, and strong affinity to hydrophobic materials [5]. Some bacteria secrete depolymerases to degrade extracellular PHAs and utilize the resulting monomer, 3-hydroxyalkanoic acid, as a nutrient. Several researchers have begun to employ depolymerases as enantioselective catalysts for biotransformation, and selective binding in immunoassays [6,7].Thus far, various surface display systems have been reported, with potential applications in the development of vaccines, bioadsorbents, biocatalysts, antibody libraries and biosensors [8][9][10]. In addition, many researchers have demonstrated the use of enzymes as target proteins for cell surface display due to their unique characteristics, such as