We Enzyme Research Team, RIKEN, investigate biopolymer synthesis from plant and marine biomass using enzyme, bacteria and plant as biocatalysts. Here, our recent updates on biosyntheses of polyhydroxyalkanoate (PHA) by bacteria and plants are summarized. Also, a new gene delivery technique using peptide-based gene carriers is briefly introduced. The future perspectives on biopolymer synthesis from plant biomass and using plant as a host producer are described at the end of this short review.