This breakthrough not only converts methane—a potent greenhouse gas—into eco-friendly materials but also overcomes key industrial bottlenecks. (Representational image)
Scientists are exploring a bacteria that consumes methane to produce biodegradable plastics.
Called Methylocystis suflitae, the bacteria offers a dual win for climate and sustainability as it brews biodegradable plastic polyhydroxyalkanoates (PHAs) at high speed.
The study highlighted that the research team optimized fermentation conditions to achieve a high PHA production rate of 11.90 mg/L/h, a critical advance for industrial use where low methane solubility often hampers efficiency.
Production of PHA from methane
Researchers revealed that they harnessed the capability of Methylocystis suflitae, a Type II methanotroph, for the production of PHA from methane. The genome analysis unveiled the presence of four paralogs of PHA synthase gene in Methylocystis suflitae. Subsequently, they elucidated the catalytic sites of each PHA synthase using protein modeling and molecular docking.
They found that four distinct genes are responsible for producing PHA synthase, a critical enzyme in plastic synthesis. Advanced protein modeling and molecular docking revealed how these enzymes efficiently bind substrates, with hydroxybutyrate and hydroxydodecanoate showing the strongest interactions.
Highest docking energies
Published in the journal Systems Microbiology and Biomanufacturing, the study revealed that hydroxybutyrate and hydroxydodecanoate demonstrated the highest docking energies among all the tested substrates, recording at − 7.5, and − 7.8 kcal/mol, respectively. The capability of Methylocystis suflitae to synthesize polyhydroxybutyrate (PHB) was evaluated by analyzing the FTIR spectrum, revealing the characteristic carbonyl (C = O) peak at 1723 cm−1.
Scientists also revealed that the breakthrough not only converts methane—a potent greenhouse gas—into eco-friendly materials but also overcomes key industrial bottlenecks.
Natural adaptability of methane-consuming bacteria
Leveraging the natural adaptability of methane-consuming bacteria to low methane environments, the research opens doors to scalable, cost-effective bioplastic production, bridging the gap between waste gas recycling and sustainable manufacturing, according to a press release.
Researchers believe that higher productivity holds significant promise for industrial PHA production, particularly in scenarios where achieving sufficiently high dissolved methane concentrations in industrial fermenters is inherently challenging, potentially enabling more efficient PHA production.
“Additionally, we determined the melting temperature for PHB produced by Methylocystis suflitae which closely aligns with the standards of commercial-grade PHB, at around 188 °C,” said researchers in the study.
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Binding affinities of PHA synthase enzyme-substrate complexes
The study included the optimization of the substrate-to-electron acceptor ratio to optimize PHA productivity. Notably, the organism exhibited a productivity value of 11.90 ± 1.34 mg PHA/L/hr.
Researchers revealed that the molecular docking analysis results provided important insights into the binding affinities of PHA synthase enzyme-substrate complexes across different genera. Strong binding energies (as low as around − 7.5 kcal/ mol) can highlight the enzyme’s efficient interaction with substrates, indicating potential for high-yield PHA production.
In this sense, Halomonas genus exhibited superior binding energy for 3HO-CoA (-9.6 kcal/mol), suggesting a specialization for medium-chain-length substrates, according to the study.
