Polyhydroxybutyrate (PHB)

Conventional synthetic plastics create a genuine, lasting environmental problem on two separate fronts: they are essentially non-biodegradable, so they persist and accumulate as pollution in soil and water, and when they are burnt instead of buried, they release dioxin, a compound linked to cancer. This double-edged problem is exactly what drove the search for genuinely biodegradable alternatives. Polyhydroxyalkanoates (PHAs), and specifically polyhydroxybutyrate (PHB), are a family of biological, thermoplastic macromolecules that are both biodegradable and biocompatible - meaning they break down naturally in the environment and are also safe enough to use inside the human body, which has opened up real medical applications including drug-delivery systems, tissue-engineering scaffolds and even heart valves. These biopolymers are not synthesised chemically in a factory but produced biologically, by a range of different microorganisms: Gram-positive bacteria such as Bacillus megaterium, Bacillus subtilis and Corynebacterium glut …