Biosynthesis of biodegradable polyester: Current research and future direction

Abstract

In last half century, petrochemical polymers have been developed, however the high stability of these polymers has led to an increase in the pollution of plastic waste. Biodegradable polymers are one solution to this problem. Polyhydroxyalkanoates (PHA) are a family of polyesters synthesized by microbes and can be used as biodegradable thermoplastics which may substitute for petrochemical polymers. At present, there are two main reasons why PHAs are not used commercially. First, the production cost of PHA is too expensive. Second, the physical properties of PHA are relatively poor compared with those of petrochemical polymers. In order to address these problems, the metabolic pathway of PHA biosynthesis was altered by genetic engineering to improve both physical properties of PHA and efficiency of PHA production. Engineering of PHA polymerase encoding genes has generated mutant PHA polymerases which are capable of higher PHA accumulation. To further address the issue of PHA production costs, transgenic plants harboring PHA biosynthesis genes from bacteria were generated. These transgenic plants have the potential to produce PHA at low cost. Further research in these areas will make the goal of having PHA commercially available, achievable.