Carbon Chemist

Tag: Methanol

  • How Synthetic Bacteria Could Revolutionize Chemical Production

    How Synthetic Bacteria Could Revolutionize Chemical Production

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    Bacteria and Methanol

    The chemical industry, which heavily relies on fossil resources to produce plastics, dyes, and artificial flavors, consumes over one million tons of these resources daily, contributing to approximately 5% of global emissions. Researchers, led by Professor Julia Vorholt, are working on reducing this dependency by developing synthetic bacteria that can convert ‘green methanol’—created from CO2 and water using renewable energy—into useful chemicals, potentially minimizing the industry’s carbon footprint. Credit: Sean Kilian

    The chemical industry primarily depends on fossil resources like crude oil to manufacture a range of chemicals, including plastics, dyes, and synthetic flavors.

    “Globally, it consumes 500 million tons per year, or more than one million tons per day,” says Julia Vorholt, Professor at the Institute of Microbiology at ETH Zurich. “Since these chemical conversions are energy-​intensive, the true CO2 footprint of the chemical industry is even six to ten times larger, amounting to about five percent of total emissions globally.” She and her team are looking for ways to reduce the chemical industry’s dependence on fossil fuels.

    Green methanol

    Bacteria that feed on methanol, known as methylotrophs, are at the center of these efforts. Containing just a single carbon atom, methanol is one of the simplest organic molecules and can be synthesized from the greenhouse gas carbon dioxide and water. If the energy for this synthesis reaction comes from renewable sources, the methanol is termed “green”.

    “There are natural methylotrophs, but using them industrially remains difficult despite considerable research effort,” says Michael Reiter, a postdoctoral researcher in Vorholt’s research group, which instead works with the biotechnologically well-understood model bacterium Escherichia coli. Vorholt’s team has been pursuing the idea of equipping the model bacterium, which grows on sugar, with the ability to metabolize methanol for several years.

    Complete restructuring of metabolism

    “This is a major challenge because it requires a complete restructuring of the cell’s metabolism,” says Vorholt. Initially, the researchers simulated this change using computer models. Based on these simulations, they chose two genes to remove and three new genes to introduce. “As a result, the bacteria could take up methanol, albeit only in small quantities,” says Reiter.

    They continued to grow the bacteria under special conditions in the laboratory for more than a year until the microbes could produce all cell components from methanol. Over the course of around 1,000 more generations, these synthetic methylotrophs became increasingly efficient, eventually doubling every four hours when fed only with methanol. “The improved growth rate makes the bacteria economically interesting,” says Vorholt.

    Optimization through loss of function

    As Vorholt’s team describes in their recently published paper, several randomly occurring mutations are responsible for the increased efficiency of methanol utilization. Most of these mutations resulted in the loss of function of various genes. This is surprising at first glance, but upon closer inspection, it becomes apparent that the cells can save energy thanks to the loss of function of the genes. For example, some mutations cause the reverse reactions of important biochemical reactions to fail. “This abolishes superfluous chemical conversions and optimizes the metabolic flux in the cells,” the researchers write.

    To explore the potential of synthetic methylotrophs for the biotechnological production of industrially relevant bulk chemicals, Vorholt and her team have equipped the bacteria with additional genes for four different biosynthetic pathways. In their study, they now show that the bacteria indeed produced the desired compounds in all cases.

    Versatile production platform

    For the researchers, this is clear evidence that their engineered bacteria can deliver on what was originally promised: the microbes are a kind of highly versatile production platform into which biosynthesis modules can be inserted according to the “plug-​and-play” principle, prompting the bacteria to convert methanol into desired biochemical substances.

    However, the researchers still need to significantly increase the yield and productivity to enable economically viable use of the bacteria. Vorholt and her team recently received an innovation fund “to further expand plans towards applications and to select products to focus on first,” says Vorholt.

    When Reiter talks about how the cultivation of bacteria in bioreactors can be optimized, he is filled with enthusiasm. “Given the challenges of climate change, it is clear that alternatives to fossil resources are needed,” he says. “We are developing a technology that does not emit additional CO2 into the atmosphere,” says Reiter. And since the synthetic methylotrophs, besides green methanol, do not require any additional carbon sources for their growth and products, they allow “renewable chemicals to be produced that do not burden the environment.”

    Reference: “A synthetic methylotrophic Escherichia coli as a chassis for bioproduction from methanol” by Michael A. Reiter, Timothy Bradley, Lars A. Büchel, Philipp Keller, Emese Hegedis, Thomas Gassler and Julia A. Vorholt, 23 April 2024, Nature Catalysis.
    DOI: 10.1038/s41929-024-01137-0



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  • Revolutionary CO2 Conversion Achieved With Copper and Carbon Nitride

    Revolutionary CO2 Conversion Achieved With Copper and Carbon Nitride

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    Reactor Where the Catalyst Is Tested for Turning CO2 to Methanol

    Researchers have developed a sunlight-powered process using copper and nanocrystalline carbon nitride to efficiently convert CO2 into methanol, marking a significant step towards sustainable fuel production and CO2 reduction. The picture above depicts the reactor where the catalyst is tested for turning CO2 to methanol. Credit: University of Nottingham

    Researchers have successfully transformed CO2 into methanol by shining sunlight on single atoms of copper deposited on a light-activated material, a discovery that paves the way for creating new green fuels.

    An international team of researchers from the University of Nottingham’s School of Chemistry, University of Birmingham, University of Queensland, and University of Ulm have designed a material, made up of copper anchored on nanocrystalline carbon nitride. The copper atoms are nested within the nanocrystalline structure, which allows electrons to move from carbon nitride to CO2, an essential step in the production of methanol from CO2 under the influence of solar irradiation. The research has been published in the Sustainable Energy & Fuels journal of the Royal Society of Chemistry.

    The Challenge of Efficiency and Selectivity

    In photocatalysis, light is shone on a semiconductor material that excites electrons, enabling them to travel through the material to react with CO2 and water, leading to a variety of useful products, including methanol, which is a green fuel. Despite recent progress, this process suffers from a lack of efficiency and selectivity.

    Carbon dioxide is the greatest contributor to global warming. Although, it is possible to convert CO2 to useful products, traditional thermal methods rely on hydrogen sourced from fossil fuels. It is important to develop alternative methods based on photo- and electrocatalysis, taking advantage of the sustainable solar energy and abundance of omnipresent water.

    Nanoscale Control for Improved Catalysis

    Dr Madasamy Thangamuthu, a research fellow in the School of Chemistry, University of Nottingham, who co-led the research team, said: “There is a large variety of different materials used in photocatalysis. It is important that the photocatalyst absorbs light and separates charge carriers with high efficiency. In our approach, we control the material at the nanoscale. We developed a new form of carbon nitride with crystalline nanoscale domains that allow efficient interaction with light as well as sufficient charge separation.”


    The process of CO2 conversion to methanol (fuel) by light. Credit: University of Nottingham

    The researchers devised a process of heating carbon nitride to the required degree of crystallinity, maximizing the functional properties of this material for photocatalysis. Using magnetron sputtering, they deposited atomic copper in a solventless process, allowing intimate contact between the semiconductor and metal atoms.

    Surprising Efficiency Gains

    Tara LeMercier, a PhD student who carried out the experimental work at the University of Nottingham, School of Chemistry, said: “We measured the current generated by light and used it as a criterion to judge the quality of the catalyst. Even without copper, the new form of carbon nitride is 44 times more active than traditional carbon nitride. However, to our surprise, the addition of only 1 mg of copper per 1 g of carbon nitride quadrupled this efficiency. Most importantly the selectivity changed from methane, another greenhouse gas, to methanol, a valuable green fuel.”

    Professor Andrei Khlobystov, School of Chemistry, University of Nottingham, said: “Carbon dioxide valorization holds the key for achieving the net-zero ambition of the UK. It is vitally important to ensure the sustainability of our catalyst materials for this important reaction. A big advantage of the new catalyst is that it consists of sustainable elements – carbon, nitrogen, and copper – all highly abundant on our planet.”

    This invention represents a significant step towards a deep understanding of photocatalytic materials in CO2 conversion. It opens a pathway for creating highly selective and tuneable catalysts where the desired product could be dialed up by controlling the catalyst at the nanoscale.

    Reference: “Synergy of nanocrystalline carbon nitride with Cu single atom catalyst leads to selective photocatalytic reduction of CO2 to methanol” by Tara M. LeMercier, Madasamy Thangamuthu, Emerson C. Kohlrausch, Yifan Chen, Craig T. Stoppiello, Michael W. Fay, Graham A. Rance, Gazi N. Aliev, Wolfgang Theis, Johannes Biskupek, Ute Kaiser, Anabel E. Lanterna, Jesum Alves Fernandes and Andrei N. Khlobystov, 6 March 2024, Sustainable Energy & Fuels.
    DOI: 10.1039/D4SE00028E

    This work is funded by the EPSRC Programme Grant ‘Metal atoms on surfaces and interfaces (MASI) for sustainable future’ www.masi.ac.uk which is set to develop catalyst materials for the conversion of three key molecules – carbon dioxide, hydrogen, and ammonia – crucially important for economy and environment. MASI catalysts are made in an atom-efficient way to ensure sustainable use of chemical elements without depleting supplies of rare elements and making most of the earth’s abundant elements, such as carbon and base metals.



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