The Opportunity for High-Performance Biomaterials from Methane

Abstract

Polyhydroxyalkanoate (PHA) biopolymers are widely recognised as outstanding candidates to replace conventional petroleum-derived polymers. Their mechanical properties are good and can be tailored through copolymer composition, they are biodegradable, and unlike many alternatives, they do not rely on oil-based feedstocks. Further, they are the only commodity polymer that can be synthesised intracellularly, ensuring stereoregularity and high molecular weight. However, despite offering enormous potential for many years, they are still not making a significant impact. This is broadly because commercial uptake has been limited by variable performance (inconsistent polymer properties) and high production costs of the raw polymer. Additionally, the main type of PHA produced naturally is poly-3-hydroxybutyrate (PHB), which has limited scope due to its brittle nature and low thermal stability, as well as its tendency to embrittle over time. Production cost is strongly impacted by the type of the feedstock used. In this article we consider: the production of PHAs from methanotrophs using methane as a cost-effective substrate; the use of mixed cultures, as opposed to pure strains; and strategies to generate a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer (PHBV), which has more desirable qualities such as toughness and elasticity.

Resource Recovery from Wastewater by Biological Technologies: Opportunities, Challenges, and Prospects

“…The use of degassing membranes has also been suggested (Bandara et al, 2011); nonetheless the energy requirements can be higher than the energy recovered. Another alternative is to use the dissolved methane as carbon source for methanotrophs, which can be combined with other biological process such as denitrification (Strong et al, 2015) and bioplastics production (Strong et al, 2016). …”

“…A less developed alternative is the use of methanotrophic bacteria to convert C1 compounds, as methane, into PHA. Methanotrophs are mainly a subgroup of gamma and alpha proteobacteria, which are present in several natural environments oxidizing methane to carbon dioxide in presence of oxygen (Strong et al, 2016). However, some methanotrophic bacteria have been found to produce the poly-3-hydroxybutyrate (PHB) homopolymer from methane under nutrient limited condition.…”

“…However, some methanotrophic bacteria have been found to produce the poly-3-hydroxybutyrate (PHB) homopolymer from methane under nutrient limited condition. This ability has drawn researchers’ interest to use methane as an alternative source to produce value-added compounds (Karthikeyan et al, 2014; Strong et al, 2016). Up to 67% of PHB can be theoretically produced (Asenjo and Suk, 1986).…”

Biotic and Abiotic Synthesis of Renewable Aliphatic Polyesters from Short Building Blocks Obtained from Biotechnology

“…[406,407] Different sources of carbon from triglycerides are highlighted in Figure 20. Methylotrophic bacteria, such as Methylobacterium/Methylosinus and Pseudomonas species (P. 135, P. methanica and P. rhodus), are capable of growing and producing P(3HB) with methanolast he only carbonsource.…”

“…However,b yu sing ap yrolysis process in af luidized bed reactor at 450-550 8C, plastic waste (e.g., polyolefins, PS, and PET) oils can be produced and then be fermented to produce mcl-PHAs. [406] This pathway of using methaned irectly is interesting because it permits the sequestering of carbon and reduces the use of organic carbon sources, such as sugars, for PHA production. [417][418][419] Additionally, C. necator exhibits the ability to accumulate PHAs (mostly 3HB monomers, with 3HV and 3HHx co-monomers) from oxidized polyethylene wax.…”