Polyhydroxyalkonate (PHA) based bioplastics are widely recognised as outstanding candidates to replace conventional plastics. Their mechanical properties are generally good, they are genuinely biodegradable, and unlike the alternatives, they don’t rely on food- or oil-based feedstocks. PHAs are polyesters produced by many microorganisms as a carbon/energy or reducing power storage material. These polyesters are the only commodity polymers that are manufactured intracellularly by microbes, making them an excellent candidate for controlled production by these cellular factories.
Commercial production of PHAs currently relies on expensive sugars and organic acids as the feedstock. Natural gas (methane) is an alternate and low-cost feedstock that is utilised by methanotrophic bacteria to form PHAs under conditions of nutrient limitation. These PHA-forming methanotrophs are the focus of many start-up companies currently commercialising PHA production technology and have already produced the brittle, low performance biopolymer PHB (polyhydroxybutyrate). The approach proposed in this work focuses on identifying and selecting for methanotrophs that form polymers with greater flexibility and higher performance than PHB (such as 3-hydroxybutyrate-co-3-hydroxyvalerate; PHBV) using high through-put DNA sequencing, molecular and engineering techniques.