Biogenesis of Medium-Chain-Length Polyhydroxyalkanoates

Abstract

Medium-chain-length polyhydroxyalkanoates (mcl-PHA) are biotechnologically useful natural products found in many bacteria. This biopolymer functions as a carbon and energy storage reservoir in cells but has physical and mechanical properties that make it a promising bioplastic with applications ranging from adhesives to medical implants. Therefore, there is much interest in understanding the biology of mcl-PHA synthesis and metabolism. Increased knowledge of PHA biology serves as a foundation for the bioengineering of PHA and its eventual use as a biologically derived product. This chapter covers the state of knowledge on mcl-PHA, including its synthesis and its central role in cellular metabolism. Moreover, this chapter discusses methods for bioengineering mcl-PHA production in bacteria as well as synthetic biology methods for its study and production in the natural mcl-PHA producer, Pseudomonas putida.

A polyhydroxyalkanoate‐based encapsulating strategy for ‘bioplasticizing’ microorganisms

“…They are polyesters of ( R )‐3‐hydroxyalkanoic acids accumulated intracellularly by different microorganisms as carbon and energy storage sources. PHAs are found to be particularly attractive for application in drug delivery due to their properties, such as optical activity, biocompatibility, non‐toxicity, thermoplasticity and biodegradability (Kniewel et al ., 2017 ). These properties depend on the monomer composition; most short‐chain‐length PHAs (sclPHAs) like polyhydroxybutyrate (PHB) are mechanically fragile and have a high melting temperature, whereas medium‐chain‐length PHAs (mclPHAs) containing 6‐14 carbon atom monomers are highly elastomeric by nature, presenting a low glass transition and a low melting temperature.…”