In a groundbreaking development that promises to revolutionize sustainable chemical manufacturing, researchers at the University of Edinburgh have unveiled an innovative microbial method to perform hydrogenation reactions using waste bread as a bio-based feedstock. This pioneering technology leverages the metabolic capabilities of Escherichia coli bacteria to produce hydrogen gas internally, thereby replacing the traditional reliance on fossil fuel-derived hydrogen in hydrogenation—a chemical transformation central to the synthesis of myriad essential products including foods, pharmaceuticals, and plastics.
Hydrogenation, a cornerstone process in industrial chemistry, typically involves the addition of hydrogen across carbon-carbon double bonds in alkenes to saturate them, using hydrogen gas produced almost exclusively from natural gas or coal. Conventional hydrogen production and utilization demand severe operating conditions such as elevated temperatures, often above 200 degrees Celsius, and extreme pressures, sometimes exceeding hundreds of atmospheres. These conditions contribute to significant energy consumption and carbon emissions, perpetuating the environmental impact of chemical manufacturing.
The Edinburgh team’s approach ingeniously circumvents these drawbacks by exploiting anaerobic fermentation of sugars derived from discarded bread waste by E. coli. Under oxygen-limited conditions, these bacteria metabolize the carbohydrate polymers, releasing molecular hydrogen as a metabolic byproduct. By conducting the enzymatic fermentation and chemical hydrogenation simultaneously in a single, sealed vessel with a palladium catalyst and target alkenes, this integrated bioprocess achieves hydrogenation at near ambient temperature and atmospheric pressure, dramatically lowering the energy footprint of the reaction.
This single-pot biohydrogenation system not only simplifies reaction logistics but also advances sustainability. Incorporating bread waste—an abundant and underutilized source of carbohydrates—transforms a pervasive food waste stream into a valuable raw material, diverting it from landfill or incineration where it would otherwise contribute to methane emissions. The comprehensive life cycle assessment performed by the researchers indicates that this method could realize carbon-negative outcomes, meaning more greenhouse gases are sequestered or offset than emitted during the process.
Moreover, the fermentation-driven hydrogen generation obviates the need for external hydrogen gas cylinders, which are costly and pose significant handling hazards due to hydrogen’s flammability and storage requirements. The process operates under mild, biologically compatible conditions, enabling safer and more accessible reaction setups while expanding the toolkit for green chemistry initiatives focusing on renewable inputs and low energy use.
The catalyst employed, palladium nanoparticles, facilitates the heterogeneously catalyzed hydrogenation of alkenes using microbially derived hydrogen in situ. While palladium remains a precious metal catalyst widely used in pharmaceutical and fine chemical industries, the team is actively researching microbial strains capable of mediating hydrogenation intrinsically, thus aiming to eliminate the need for metallic catalysts altogether. This would further enhance the biocompatibility and sustainability profile of the technology.
Potential applications for this microbial hydrogenation extend far beyond food manufacturing, which traditionally utilizes hydrogenation to convert liquid oils into semi-solid fats for texture and shelf stability improvements. Pharmaceutical compound synthesis, the production of specialty chemicals, and polymer precursor generation are all poised to benefit from this platform. By reimagining hydrogenation as a biologically integrated chemical transformation, opportunities emerge for both decentralized manufacturing and utilization of locally sourced bio-waste streams.
Professor Stephen Wallace, the lead investigator and Personal Chair of Chemical Biotechnology at the University of Edinburgh, highlights that this approach disrupts the conventional dependence on fossil fuel-derived hydrogen, combining microbiology, catalysis, and waste valorization into a scalable solution. “What we’ve shown is that living cells can supply that hydrogen directly, using waste as a feedstock, and do so in a way that can actually be carbon-negative,” he notes, underscoring the transformative potential for sustainable manufacturing.
The research, detailed in the journal Nature Chemistry, was supported by funding from UK Research and Innovation (UKRI), the European Research Council (ERC), and the Industrial Biotechnology Innovation Centre (IBioIC), demonstrating a collaborative commitment to advancing bio-based industrial processes. The team is currently pursuing expansion of substrate scope, exploring other types of metabolic alkenes as reaction targets, and optimizing microbial hosts to maximize hydrogen yield and catalytic efficiency.
Complementing this scientific advance, Edinburgh Innovations, the university’s technology commercialization arm, is actively encouraging industry partners to collaborate and translate this technology into practical applications. Dr. Susan Bodie, Director of Innovation Development and Licensing, emphasizes the transformative promise of microbial engineering to valorize waste and foster a green manufacturing revolution in the UK and globally.
Industry stakeholders recognize the disruptive nature of this innovation. Douglas Martin, Founder and CEO of MiAlgae—which develops biotechnology-derived omega-3 ingredients—affirms the potential for such biotechnologies to overhaul industrial supply chains, minimize environmental footprints, and support sustainable economic growth. His company’s recent expansion also highlights the growing commercial viability of deploying engineered biological systems at scale.
This biohydrogenation method exemplifies the University of Edinburgh’s dedication to environmental leadership through advanced research and cross-sector partnerships. As part of the institution’s broader mission to achieve carbon neutrality by 2040, this technology aligns with global objectives targeting decarbonization of chemical production—a sector responsible for a considerable portion of industrial greenhouse gas emissions.
Intrinsically integrating microbial metabolism and catalytic chemistry into seamless processes is emblematic of the future direction for green chemistry. By converting ubiquitous waste streams into valuable chemical feedstocks without intensive energy inputs or harmful emissions, this technology sets a high bar for sustainability and circular economy principles in manufacturing.
The research team envisions a future where industrial hydrogenation no longer burdens the environment but instead harnesses the power of living systems to deliver carbon-negative solutions. Expanding this platform promises to unlock new pathways to produce a swath of chemicals essential for modern life, all fueled by the simplest and most sustainable resource: microbial metabolism thriving on everyday waste.
Subject of Research: Not applicable
Article Title: Native H2 pathways enable biocompatible hydrogenation of metabolic alkenes in bacteria
News Publication Date: 23-Feb-2026
Web References: Wallace Lab
Image Credits: Dr Mirren White, School of Biological Sciences, University of Edinburgh
Keywords
Applied sciences and engineering, Life sciences
