Polyhydroxyalkanoates (PHA) toward cost competitiveness and functionality

TLDR

Polyhydroxyalkanoates (PHA) are bacterial bioplastics produced at industrial scale, yet commercialization is hindered by high costs, unstable molecular weights and structures, and complex bioprocessing that limits carbon conversion and downstream separation. This review aims to reduce PHA production complexity by targeting contamination‑resistant extremophiles, particularly Halomonas spp., and applying next‑generation industrial biotechnology engineering strategies to enhance yield and diversity. The authors describe engineering approaches that employ extremophilic bacteria, especially Halomonas spp., to boost PHA biosynthesis and diversify polymer properties.

Abstract

Polyhydroxyalkanoates (PHA) have been produced by several bacteria as bioplastics in industrial scales. PHA commercialization has been challenging due to its complexity and the associated high cost together with instabilities on molecular weights (Mw) and structures, thus instability on thermo- and mechanical properties. PHA high production cost is related to complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and poor growth of microorganisms as well as complicated downstream separation. To reduce complexity of PHA production, robust microorganisms that are contamination resistant bacteria have been targeted especially extremophiles, developments of engineering approaches for extremophiles especially Halomonas spp. for better PHA production have been successfully conducted and termed as "next generation industrial biotechnology" (NGIB). Diverse PHA can also be produced by engineering Halomonas or Pseudomonas spp. This review introduces recent advances on engineering bacteria for enhanced PHA biosynthesis and diversity.