Longitudinal airflow can sharply suppress the drifting and ablation of the electrical arc formed between a train’s pantograph and overhead contact wire, according to a modeling and experimental study of pantograph–catenary systems under low-pressure conditions. The researchers built a magnetohydrodynamic model that coupled electric, magnetic, thermal, fluid and arc-motion dynamics, then tested the method in a vacuum chamber with copper and carbon electrodes. In experiments conducted at atmospheric pressure, increasing the airflow to 45 metres per second reduced the measured arc drift height from 27.6 millimetres to zero and shortened the arc-root distance from 51.3 to 3.9 millimetres. The same airflow setting also produced progressively less carbon-electrode damage, supporting the proposal as a possible current-collection control method for railways operating at high altitude.

The need for such control arises because the pantograph–catenary system carries the electrical energy used by electric trains, while the stability of its contact strongly affects operating safety and efficiency. Lower atmospheric pressure presents a particularly difficult environment. The study notes that reduced air density and breakdown-field strength can lower the ignition threshold for pantograph–catenary arcs, increase their frequency and duration, and enlarge the region affected by arcing. Repeated arcing can cause irreversible high-temperature ablation and electrical wear on contact wires and pantograph strips. It can also generate broad-band electromagnetic interference that may affect onboard signalling and traction-control systems, with potential consequences including insulator flashover and disruption of the traction network. These background risks motivate efforts to understand and restrain the spatial movement of arcs in plateau environments.

Existing arc models include the Cassie and Mayr black-box approaches, which support analysis of interactions between arcs and traction-network circuits but do not represent an arc’s changing spatial shape. Magnetohydrodynamic models offer a more physical alternative by coupling electromagnetic, flow and thermal fields. Previous work represented crosswind effects on pantograph–catenary arcs and examined how decreasing pressure affects arc-root jumping, in which the root forms at a new location after the elongated column reaches a critical length. Other studies have shown that magnetic fields can stabilize welding and switching arcs. Airflow regulation, however, has been investigated more extensively in welding than in pantograph–catenary systems, whose dissimilar electrodes, high operating speed, open environment, changing electrode gap and constrained vehicle installation space make their arc dynamics more complicated.

The new model represents an arc initially 6 millimetres long and 2 millimetres in diameter between a copper anode and a carbon cathode. It includes the surrounding air, both electrodes and a central longitudinal-airflow channel beneath the copper electrode, including a 1.5-millimetre control-airflow inlet. A separate inlet represents train-induced airflow and was set to 40 metres per second. Calculations covered pressures of 101, 80 and 60 kilopascals, longitudinal airflow from zero to 80 metres per second and a total simulation time of 25 milliseconds. Air properties were adjusted with pressure, while the electrodes were assigned distinct densities, resistivities, thermal conductivities and heat capacities. The governing equations represented electrical potential and current, magnetic-vector potential, mass and momentum conservation, energy conservation, viscous dissipation, Joule heating and net volumetric radiation.

The calculations use several explicit simplifications. Arc ignition is omitted, and the plasma is treated as being in local thermodynamic equilibrium. Flow in the air and arc domains is assumed laminar and incompressible, while metal vapour generated by electrode evaporation and phase change is excluded. These assumptions make it possible to examine large-scale arc motion and temperature distribution but prevent the simulation from directly calculating electrode mass loss, crack width or crater area. Copper was assigned the anode and carbon the cathode; a Gaussian distribution represented current entering through the copper electrode, and the bottom of the carbon electrode was grounded. The air boundary was treated as magnetically insulated, and the initial temperatures were set to 300 kelvin for the air and electrodes and 5,000 kelvin for the arc domain. The experimental apparatus was separate from the numerical model and provided direct physical measurements of damage.

Without longitudinal airflow, the simulated arc passed through two stages. During the first 10 milliseconds, its column elongated continuously, bent under airflow influence, and developed greater drift height and arc-root distance. From 10 to 25 milliseconds, the column and root distance fluctuated through repeated shortening and elongation. The authors associate this behaviour with the electrical and mechanical limits of the arc: once a column reaches a critical length, the voltage and energy available between the electrodes may no longer sustain continuous burning, and a shorter path of lower resistance may form on the electrode surface. The resulting root “jump” shortened the column before airflow stretched it again. Arc development became faster and both drift height and root distance increased as pressure fell. Temperature briefly exceeded 10,000 kelvin and reached a maximum within roughly two to three milliseconds before fluctuating, while arc voltage rose as the column lengthened and resistance increased.

Longitudinal airflow changed these trajectories in the simulations. As speed increased, drift height, root distance and temperature all declined, with the greatest reductions occurring at lower airflow speeds before the curves began to level off. At 101 kilopascals, the calculated drift height fell from 37.5 millimetres without control airflow to zero at 45 metres per second, while root distance decreased from 57.3 to 3.7 millimetres and temperature dropped from 12,900 to 8,650 kelvin. The airflow needed to eliminate drift was 45, 40 and 35 metres per second at pressures of 101, 80 and 60 kilopascals, respectively; speeds required to bring root distance below 5 millimetres were 45, 40 and 30 metres per second. The authors attribute the stronger response at lower pressure to reduced plasma density, which weakens the arc’s inherent rigidity, Lorentz force and thermal buoyancy, allowing airflow load to become a more dominant influence on its motion.

The temperature response also revealed a practical plateau. The researchers defined the optimal airflow speed as the point after which increasing speed by 5 metres per second changes arc temperature by less than 3 per cent. At atmospheric pressure this occurred at 40 metres per second, compared with 30 metres per second at 60 kilopascals. The reported temperature reduction was 33.8 per cent at 101 kilopascals and 38.1 per cent at 60 kilopascals. Airflow strengthened convective heat removal, which lowered plasma temperature and, in turn, increased deionization and reduced Joule heating. Once thermal exchange approached saturation and the minimum temperature required for self-sustaining arc combustion was approached, further increases in speed produced little additional cooling. The model therefore indicates that the airflow speeds required for control decline as ambient pressure falls.

Laboratory testing used a vacuum chamber capable of controlling pressure with an accuracy of plus or minus 100 pascals, a constant-current supply rated from zero to 150 amperes, an arc igniter, a fan with continuously adjustable airflow from zero to 60 metres per second, a high-speed camera and an oscilloscope. Airflow at the electrode outlet was measured with an anemometer accurate to plus or minus 0.5 metres per second. The camera operated at 6,400 frames per second with an exposure of five microseconds, while each two-second arc test was repeated five times and the mean was reported. Tests at 101 kilopascals used airflow speeds of zero, 20, 30 and 45 metres per second. Without control airflow, high-speed images showed increasing arc drift. At 45 metres per second, drift was virtually absent during the final development phase and root distance was substantially shortened, with observed morphologies broadly consistent with the numerical results.

The experiments also found reductions in carbon-electrode ablation that increased with airflow speed. Microscopy showed shorter ablation areas, smaller craters and narrower crack propagation as the controlled airflow rose. The maximum crack width was 66.7 micrometres without airflow and decreased at higher speeds, while analytical weighing showed progressively less mass loss from the carbon electrode. The proposed mechanism is that stronger airflow promotes arc-root slippage, shortening the time the root remains at one point, while convective cooling lowers temperature and local energy density. These are experimental observations rather than direct outputs of the simulation: because the model omits electrode evaporation and metal-vapour transport, it cannot quantitatively predict ablation rates or near-electrode energy balances. The study therefore demonstrates reduced damage under its controlled laboratory conditions, not a complete first-principles calculation of all processes responsible for electrode wear or a proven field performance level in operating plateau railways.

Subject of Research: Experimental and numerical evaluation of airflow control of pantograph–catenary arcs at low pressure.

Article Title: Research on regulation method for suppression of pantograph-catenary arc by airflow in low-pressure environment

Article References: Xu, Z., Wang, S., Dong, K., & Gao, G. (2026). Research on regulation method for suppression of pantograph-catenary arc by airflow in low-pressure environment. iScience, 29(11), Article 117951. https://doi.org/10.1016/j.isci.2026.117951

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117951

Keywords: pantograph–catenary systems, railway electrification, electric arcs, low-pressure environments, longitudinal airflow, magnetohydrodynamic modelling, electrode ablation, high-speed rail, plateau railways, arc suppression, Research, regulation

Could a magnetic field be used to identify in advance which OLEDs will keep smartphone and TV screens bright the longest? A KAIST research team has developed a technique that predicts OLED lifetime by analyzing small changes in brightness caused by a magnetic field. The technique reduces the need for long operating tests and is expected to support the development of longer-lasting displays.

Imagine a voice message from a manager asks an employee to watch for an urgent email. The email

Self-driving electric taxi fleets could make transportation more efficient and sustainable, but only if vehicles can continuously make smart decisions about where to drive and when to recharge. Researchers at Chalmers University of Technology in Sweden have now developed a new optimization method that enables near-optimal large-scale fleet control while accounting for uncertainties that arise in real-world transportation systems.

Author: Iñigo Careaga, strategy & communication manager, CIC energiGUNE

Lithium and sodium are neighbours in the periodic table. Both are alkali metals, both have a single electron in their outer shell, and both can be used to shuttle ions between two electrodes to store and release electrical energy. At first sight, replacing lithium with sodium in a rechargeable battery might therefore seem straightforward.

There are good reasons to try. Sodium is widely available and sodium-ion batteries can rely on electrode materials containing abundant elements such as iron and manganese. But chemical similarity does not mean electrochemical equivalence. A sodium ion is larger and heavier than a lithium ion, and its interaction with the materials surrounding it is different. As a consequence, replacing Li⁺ with Na⁺ changes much more than the identity of the charge carrier.

The electrodes have to accommodate a different ion. Their structures may respond differently as sodium is inserted and removed. The electrolyte has to transport and solvate it. New interfaces form between the electrolyte and the electrodes. Even graphite, the standard anode material of most commercial lithium-ion batteries, does not store sodium under conventional conditions nearly as effectively as it stores lithium ¹.

A sodium-ion battery is therefore not simply a lithium-ion battery containing a different element. Understanding why requires looking at what happens to sodium once it enters the battery.

Graphite does not play by the same rules

Charging a conventional lithium-ion battery involves moving lithium ions from the positive electrode through the electrolyte and storing them in the negative electrode. Graphite is particularly good at this job. Its carbon atoms are arranged in sheets, and lithium can reversibly occupy the spaces between them, a process known as intercalation. It would be convenient if sodium behaved in the same way. It largely does not.

The poor ability of conventional graphite to accommodate sodium has long been one of the reasons why lithium-ion concepts cannot simply be transferred to sodium-ion batteries. Instead, one of the most widely studied negative-electrode materials is hard carbon ².

Hard carbon is still carbon, but structurally it is very different from graphite. Rather than a regular stack of extended carbon sheets, it contains disordered graphitic domains, defects and pores. This disordered architecture provides environments in which sodium can be stored, but it also makes the underlying mechanism considerably harder to describe.

Where exactly does the sodium go? Researchers have proposed contributions from adsorption at defects and surfaces, insertion between graphitic layers and storage associated with nanopores. The relative importance of these mechanisms depends on the structure and microstructure of the carbon. This is more than a microscopic detail: where and how sodium is stored determines the voltage profile, reversible capacity, first-cycle losses and, ultimately, the energy that a complete cell can deliver.

Researchers at CIC energiGUNE and collaborators have studied this connection between charge-storage mechanisms, carbon structure and electrochemical performance ³. Their analysis highlights an important point: maximizing the amount of sodium that an anode can store is not enough. The potential at which that storage occurs and the irreversible losses during the first cycle are equally important when the material is incorporated into a full battery.

The problem is therefore not simply to find a carbon that accommodates more sodium. It is to understand how its structure stores sodium and then engineer that structure so that capacity, voltage and efficiency improve together. This has led researchers to explore different ways of controlling hard-carbon structure, including the use of lignocellulosic biomass as a precursor. Work has shown that even apparently simple processing decisions, such as acid treatment of the biomass precursor, can affect the resulting carbon and its behaviour as a sodium-ion anode ⁴.

And the negative electrode is only half of the problem. At the positive electrode, sodium ions have to repeatedly leave and re-enter a solid structure. Layered transition-metal oxides are attractive candidates because sodium can be reversibly extracted from and inserted into spaces between layers of metal and oxygen atoms. Compositions based on relatively abundant elements such as iron and manganese are particularly interesting ⁵.

Again, however, accommodating sodium is not enough. The host structure has to survive the process. A useful example is the layered oxide P2-Na₂/₃[Fe₁/₂Mn₁/₂]O₂, investigated by researchers from CIC energiGUNE and collaborators ⁶. The material can provide high capacity, but its long-term stability strongly depends on the voltage range over which it is operated.

This produces a familiar battery dilemma. Increasing the operating voltage can increase the amount of energy extracted from a material. But pushing the electrode further can also trigger structural transformations that make subsequent cycles less reversible.

The researchers compared cells operating in different voltage windows and combined electrochemical measurements with structural characterization and theoretical calculations. Above approximately 4.0 V versus Na+/Na, the cathode undergoes a high-voltage phase transition. Avoiding this transition improves capacity retention, revealing a direct connection between the structural state of the electrode and its long-term electrochemical behaviour.

Changing the chemical composition can also alter this structural response. In another study, researchers investigated the effect of introducing titanium into sodium manganese-rich layered oxides ⁷. A certain degree of Ti substitution helped the crystal structure accommodate electrochemically induced strain. Too little was insufficient to stabilize it, while further substitution introduced other destabilizing effects.

Other studies have approached the same problem from a different angle, examining how the precise stoichiometry of P2 layered oxides affects their performance ⁸, or following their structural evolution under different current rates and dopants using operando techniques ⁹. The lesson is that there is no single property called “a good sodium cathode”. Composition, atomic arrangement, voltage and cycling conditions are interconnected. Even an element that does not directly provide the stored charge can determine how well the electrode survives sodium repeatedly moving through its structure.

A different chemistry

Layered oxides are not the only possible positive electrodes. Sodium chemistry allows other structural families to be explored.

One particularly instructive example is NaFePO₄, the sodium analogue of the well-known lithium iron phosphate chemistry. Researchers involving CIC energiGUNE have used in situ X-ray diffraction to follow how NaFePO₄ changes during sodium insertion and extraction ¹⁰. They have also shown that the reaction mechanism itself depends on how rapidly the electrode is charged or discharged ¹¹.

This is a subtle but important point. We often describe an electrode material as if it had a fixed reaction mechanism. In practice, what happens inside it can depend on how the battery is operated. Computational work has gone further by investigating sodium diffusion in NaₓFePO₄ ¹². Combining experiments and modelling in this way makes it possible to connect what is observed at the battery level with the motion of ions through an atomic structure.

But even understanding both electrodes is not enough. Between them lies the electrolyte, and the sodium ion spends much of its journey there. It becomes surrounded by solvent molecules, travels across the cell and eventually reaches an electrode surface. At that interface the electrolyte can decompose, producing a solid-electrolyte interphase, or SEI.

This apparently thin layer can have a disproportionate influence on battery behaviour. Researchers at CIC energiGUNE have investigated both the composition and evolution of the SEI in sodium-ion electrodes ¹³ and, more broadly, the relationship between electrode-electrolyte interphases, transport properties and electrochemical performance in non-aqueous sodium-ion batteries ¹⁴.

The interface illustrates particularly well why changing lithium for sodium is not a simple substitution. The chemistry of the ion influences its solvation, its transport and the decomposition reactions that occur when it reaches an electrode. A material that can reversibly store sodium may still perform poorly if the interface around it continuously consumes electrolyte or sodium during cycling.

This is why sodium-ion research has to consider the cell as a system. Graphite may have to give way to hard carbon. Positive electrodes require structures able to tolerate repeated sodium insertion and extraction. Electrolytes and additives have to create suitable transport conditions and stable interfaces.

And every attempt to solve one of these problems can affect the others.

Sodium is not the new lithium

Lithium has a fundamental advantage that materials engineering cannot simply remove: it is the lightest metal and has a very low electrochemical potential. Sodium is heavier and its electrochemical potential is less favourable, placing intrinsic constraints on the gravimetric energy density that sodium-ion batteries can reach.

That does not necessarily make sodium a worse battery chemistry. Energy density is only one parameter of an electrochemical storage system. Cost, raw-material availability, lifetime, power, safety and operating temperature can become equally important depending on the application. A battery designed for a mobile phone, an electric vehicle or stationary storage does not necessarily have to optimize the same variables. And sodium chemistry itself offers several possible ways of balancing them.

CIC energiGUNE researchers have explored, for example, low-cost phosphate-based cathodes for aqueous sodium-ion batteries ¹⁵, Prussian Blue compounds as positive electrodes in aqueous systems ¹⁶, alternative sodium layered oxides [5,8,9], hard-carbon anodes [2,3,4] and even materials such as NaTiOPO₄ designed to modify or potentially avoid some of the interfacial problems normally associated with sodium-ion anodes ¹⁷.

These are not different routes towards exactly the same battery. They represent different ways of deciding which compromises are acceptable.

This changes the original question. The relevant challenge may not be how to make sodium behave as much like lithium as possible. Research on hard carbons shows that sodium may require a different type of host structure. Work on layered oxides shows that extracting more energy from an electrode can alter its structure and compromise its stability. Studies of NaFePO₄ show that the reaction pathway itself can depend on cycling conditions. And research on interfaces shows that storing sodium reversibly is only part of the problem: the chemistry taking place around the active material matters as well.

Sodium-ion batteries are therefore not lithium-ion batteries in which one element has simply been exchanged for another. Changing the ion changes the materials that host it, the structures they adopt, the reactions they undergo and the interfaces they form.

Sodium may not need to beat lithium at its own game. The more interesting question is whether understanding its different chemistry will allow us to play a different one.

 

The BRTA is a consortium that remains a step ahead of future socio-economic challenges worldwide and in the Basque Autonomous Community; it addresses them through research and technological development, thus projecting itself internationally. The BRTA centres collaborate to generate knowledge and transfer it to Basque society and industry so as to make them more innovative and competitive. The BRTA is an alliance of 17 R&D centres and cooperative research centres with the support of the Basque Government, the SPRI and the Chartered Provincial Councils of Araba, Bizkaia and Gipuzkoa.

 

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A space telescope built to study distant galaxies has unexpectedly discovered a comet about 810 million miles from Earth. The find shows that even a mission looking far beyond our solar system can reveal previously unknown objects much closer to home. The European Space Agency’s Euclid telescope detected the comet in images collected between September […]

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Stanford researchers recently revealed how a seemingly physics-defying wireless communication technology works. The new technology, called thermal noise communication, harnesses background static that normally is the bane of radio, cellular and other wireless signals. In their new study published in the Proceedings of the National Academy of Sciences, the team showed how a transmitter could deliver data to a receiver without any actively produced signal by manipulating tiny oscillations in voltage.

Reducing carbon dioxide emissions from steelmaking requires more efficient ways to turn iron ore into iron. While hydrogen-based technologies offer a promising path toward lower-carbon steel production, conventional blast furnaces will remain important during the transition. Understanding how iron ore behaves inside these furnaces could help improve their efficiency and stability.

RMIT researchers have turned coffee waste into 3D-printed architectural forms, opening a potential pathway towards more sustainable, low-carbon construction. The project brings together scientific, architectural and engineering expertise.

Certain viruses attack bacteria and can sometimes clear antibiotic-resistant infections. Researchers said they had tailored a virus to attack one patient’s illness.

Scientists have discovered a class of metal that can unexpectedly resist extreme cold using an unusual mechanism. Normally such temperatures would make similar materials brittle and vulnerable to breaking. The findings point to new principles for designing materials for cryogenic environments.

An international team led by University of California, Berkeley, Lawrence Berkeley National Laboratory and the University of Oxford has uncovered ¹ a novel microscopic mechanism that allows two metal alloys to remain remarkably damage-tolerant at just 20 kelvin, or -253°C.

Most metals become stronger when they are cooled, but some pay a price. The class of metals called body-centred cubic metals (such as iron, tungsten and chromium) have a particular atomic structure which can make them increasingly brittle as temperatures fall. At extremely low temperatures, a crack that might normally be absorbed by the metal bending or deforming can instead cause it to fracture.

The new study discovered that two experimental niobium-titanium-based alloys can avoid this problem even at just 20 kelvin, or -253°C. The metals remained remarkably resistant to cracking, with no measurable transition to brittle behaviour at the lowest temperature tested. The researchers found that this is due to the alloys effectively switching how they deform as they enter the deep freeze.

Normally, bending and deformation of body-centred cubic metals relies heavily on the movement of line-like defects in their crystal structure known as dislocations. At low temperatures, these become increasingly difficult to move, restricting the material’s ability to deform around a crack and making a fracture more likely.

In the alloys studied, however, a different process takes over. The researchers observed nanoscale ‘twinning’, in which small regions of the crystal reorganise into mirror-image orientations, coupled with a local transformation of the crystal structure. When these newly formed structures reach the boundaries between neighbouring crystals, they create concentrated points of stress that trigger new defects in the metal. These defects then allow the material to keep deforming rather than cracking.

The process is a little like a road network responding to frozen, blocked roads by opening new routes. As the conventional routes for deformation become increasingly difficult to use, the formation of twins creates new sites from which the defects needed for deformation can emerge. This helps the metal to absorb the forces building up around a crack, rather than breaking.

The discovery could provide scientists with a new strategy for designing metals capable of operating in exceptionally cold environments, including for energy, transport and aerospace sectors.

To find out how the alloys behaved in such extreme cold, the researchers used the Engin-X instrument at the ISIS Neutron and Muon Source in Oxfordshire. They cooled samples to around -253°C using gaseous helium. They then exposed the samples to a beam of neutrons while a testing machine pulled them from either end, precisely measuring how much force they could withstand and how far they stretched before breaking.

The team then used powerful electron microscopes to examine the tested metal at extremely small scales, allowing them to see the tiny structural changes that had taken place around cracks and inside the material. They also used atom-probe analysis to map the distribution of individual elements, alongside computer modelling to understand how the different mechanisms worked together to prevent brittle failure.

The study involved researchers from the University of California, Berkeley; Lawrence Berkeley National Laboratory; the University of Oxford; the University of Bristol; the ISIS Neutron and Muon Source, Science and Technology Facilities Council; the University of California, Irvine; Pacific Northwest National Laboratory; Texas A&M University; and Nanyang Technological University in Singapore.

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When it comes to deciding the fate of the planet, Colleen Golja always thought science and reason would have a seat at the table. That was until one morning last September in London, when the climate researcher took part in the first in a series of war games. The goal: to prevent an uncontrolled global race to develop a technology aimed at cooling the planet but that comes with vast, unknown risks that could reshape life on Earth.

“I thought that would be such an easy thing. Like, we can all agree to do ethical research and make sure it's for the better of all humans,” she told WIRED. “And boy, was I wrong.”

The simulation, titled Exploring Geopolitical Tipping Points and Climate Cooling Strategies, saw a couple dozen foreign-relations experts, scientists, military personnel, and former government officials from across the world convene in a meeting room at Queen Mary University of London. After making introductions over coffee and little yogurts, they sat at tables arranged in a square with the name of the country or organization each person was playing: national governments, climate NGOs and nonprofits, indigenous groups, and tech companies. Golja was assigned to provide technical advice to help participants make scientifically literate decisions.

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Authors: Eider Fernandez & Igor Baroja-Careaga, Esneki Zentroa (Leartiker S.COOP)

 

Probiotics are part of a rapidly expanding field of research. They are live microorganisms that, when administered in adequate amounts, may confer health benefits[1]. Among the most extensively studied probiotics, some species of Lactobacillus and Bifidobacterium have been associated with the maintenance of gut microbiota balance and with several physiological functions[2]. Producing these microorganisms usually requires nutrient-rich culture media. But what if such bacteria could be obtained from a food by-product nowadays regarded as waste? This question formed the starting point of a study carried out by Esneki Dairy Centre – Leartiker to assess the potential of cheese whey as a substrate for producing microbial biomass enriched in microorganisms with probiotic potential.

The challenge of cheese whey

Cheesemaking inevitably generates substantial amounts of whey: a yellowish liquid released from the curd that still carries lactose, soluble proteins, minerals and other valuable compounds. In fact, whey can represent around 85% of the original milk volume used in cheese production[3].

Despite this nutritional richness, whey remains a difficult stream to manage for many artisanal dairies. This is particularly true in the Basque Country, where many cheesemaking farms are small, family-run businesses located in rural areas[4]. Its highly perishable nature means that whey must be preserved or processed soon after production, making storage, collection and transport especially challenging when volumes are small and geographically dispersed.

Moreover, uncontrolled whey discharge results in a high organic load that can affect aquatic ecosystems. Paradoxically, the same nutrients that make cheese whey a potential pollutant are also what give it considerable biotechnological value.

A natural culture medium

From a microbiological standpoint, cheese whey is not merely a residual stream, but a naturally nutrient-rich matrix[5]. Its lactose content, together with soluble proteins, minerals and other available compounds, provides a favourable environment for the growth of lactic acid bacteria, widely used microorganisms in fermented foods and increasingly explored for their probiotic potential.

The working hypothesis was simple: by steering whey fermentation under controlled conditions, it could be possible to recover a biomass enriched in microorganisms of interest, while at the same time increasing the stability and value of the by-product itself.

To explore this possibility, several fermentation strategies were tested using whey generated during the production of blue cheese from pasteurised cow’s milk. The study compared three different approaches:

• Fermentation of previously pasteurised whey (Protocol 1).
• Fermentation of whey after a deproteinisation step (Protocol 2).
• Direct fermentation of raw whey, without any prior treatment (Protocol 3).

Two different blends of commercial microorganisms, inspired by the naturally diverse microbial communities found in kefir, were also evaluated. These included; Choozit Kefir DV LYO 1000L (Danisco) (starter culture A) and Ferlac Kefir Type C (Abiasa) (starter culture B). Additionally, unfermented whey (that is, whey to which no starter cultures were added and which was not subjected to fermentation) from each protocol was analysed as a control sample. Controlled fermentation processes were carried out under monitored conditions. Throughout the fermentation, key parameters were monitored, including temperature (25 ± 1 °C), incubation time (16 ± 1 h for starter culture A and 21 ± 1 h for starter culture B) and pH evolution, with fermentation being considered complete once the pH fell below 4,6. These measurements allowed the identification of the conditions that most effectively supported the growth and enrichment of the target microbial populations.

 

Exploring the microbiome through metagenomics

However, assessing the success of a fermentation process requires more than simply determining how many microorganisms grow. It is also essential to identify which species are present and how the microbial community changes over time.

Traditional culture-based microbiological methods remain fundamental tools for quantifying and isolating viable microorganisms. Yet they have important limitations when complex microbial communities need to be characterised, as they only detect microorganisms able to grow under the selected culture conditions. As a result, part of the microbial diversity present in the sample may remain undetected. To obtain a more comprehensive view of the microbial community, the study incorporated high-throughput amplicon sequencing, an approach that enables the direct analysis of DNA present in a sample and the identification of microorganisms regardless of their ability to grow under laboratory conditions.

Bacterial communities were characterised by amplifying the V4 region of the 16S rRNA gene, one of the most widely used markers in bacterial diversity studies. Fungal and yeast communities were analysed through the ITS region — the Internal Transcribed Spacer — which is considered the standard marker for fungal diversity studies.

Sequencing was performed using Illumina technology, generating approximately 100,000 reads per sample for bacteria and around 40,000 reads for fungi and yeasts. These sequences were then compared against specialised databases to determine the identity of the microorganisms present and estimate their relative abundance.

Before interpreting the results, sequencing depth was assessed using rarefaction curves. These curves showed a clear trend towards saturation, indicating that most of the microbial diversity present in the samples had been adequately captured.

Which protocol worked best?

High-throughput amplicon sequencing revealed clear differences among the fermentation strategies tested.

Fermentations carried out using raw whey (Protocol 3) maintained a more diverse bacterial community than those in which the whey had first been subjected to thermal treatment (Protocol 1 and Protocol 2), as can be seen in Figure 1, as can be seen in Figure 1, the number of observed microbial taxa increases with sequencing depth. This suggests that the partial preservation of the native microbiota originating from the cheesemaking process may play an important role in shaping the fermentation outcome.

 

 

 

In contrast, the diversity of moulds and yeasts decreased. This trend may be related to the origin of the whey, which was obtained from blue cheese production, where specific mould (Penicillium roquefoti) species are deliberately enriched during manufacture. The competitive advantage of these dominant fungi appears to favour the development of a more specialised microbial community, reducing the abundance and diversity of other microbial populations present in the whey (Figure 2).

 

 

Principal coordinates analysis (PCoA) based on Jaccard distances (Figure 3) showed a clear separation among the different fermentation protocols, indicating that each strategy gave rise to distinct microbial communities. In parallel, the relative abundance of profiles (Figure 4) made it possible to visualise how particular species increased or decreased depending on the conditions applied.

 

 

 

 

Amplicon sequencing also enabled the identification of the dominant microorganisms during the process. In most samples, Lactococcus lactis was particularly abundant. This result was expected, as this bacterium was included in the commercial starts cultures used and is widely employed in dairy fermentations. However, some fermentation conditions, particularly those involving starter culture B, also favoured the development of species such as Lacticaseibacillus rhamnosus and Bifidobacterium animalis, wich were also present in the commercial starter culture. These microorganisms are frequently associated with probiotic applications[6]^,[7]^,[8].

To identify the most suitable protocol for producing a fermented whey enriched in microorganisms with probiotic potential, both microbial abundance (including aerobic mesophilic bacteria, yeasts and moulds) and the diversity of the resulting microbial communities were evaluated. The highest microbial counts were obtained in whey samples produced using Protocol 3, which was based on raw whey, and fermented with starter culture B. (Average counts of 8.2 log CFU/mL were obtained with starter culture A, and average counts of 8.5 log CFU/mL with starter culture B).

Furthermore, as mentioned previously, the highest levels of microbial diversity were observed in the samples produced using Protocol 3, where fermentation was carried out directly on raw whey without prior heat treatment.

 

Overall, the results pointed to the most effective strategy also being the simplest from a technological perspective: the direct fermentation of raw whey, without prior thermal treatment using starter culture B. This approach maintained high microbial diversity while reducing energy requirements and simplifying the overall process.

An opportunity for the circular economy

Beyond the microbiological results, the broader relevance of this work lies in showing that the role of whey within the cheesemaking chain can be reconsidered.

Rather than being treated as a waste stream associated with management costs, whey can be viewed as a raw material capable of supporting valuable biotechnological processes. Controlled fermentation not only helps stabilise whey but also makes it possible to harness the nutrients it still contains to generate added-value microbial biomass.

Such strategies are closely aligned with the principles of the circular bioeconomy, in which by-products are no longer seen as the end of a production chain, but as the starting point for another. In a context where sustainability and efficient resource use are increasingly important, initiatives of this kind show how microbiology and omics technologies can help turn an environmental challenge into an opportunity for innovation.

 

The PRO2O project (grant agreement No. 00003-BIO2022-48) was funded through the 2022 Bioeconomy Innovation Projects funding programme of the Basque Government’s Department of Economic Development, Sustainability and Environment.

References

[1] Guarner F, Requena T, Marcos A. Consensus statements from the Workshop “Probiotics and Health: Scientific evidence”. Nutr Hosp. 2010 Sep-Oct;25(5):700-4. PMID: 21336423.

[2] Martin, A. J. M., Serebrinsky-Duek, K., Riquelme, E., Saa, P., & Garrido, D. (2023). Microbial interactions and the homeostasis of the gut microbiome: the role of Bifidobacterium. Microbiome Research Reports, 2. https://doi.org/10.20517/mrr.2023.10

[3] González Siso, M. I. (1996). The biotechnological utilization of cheese whey: A review. Bioresource Technology, 57(1), 1–11. https://doi.org/10.1016/0960-8524(96)00036-3

[4] Esneki Zentroa – Leartiker (2022). “El sector quesero en Euskadi 2021”. Available at: El-sector-quesero-en-Euskadi.pdf

[5] Figueroa Pires, A., garcía Marnotes, N., Díaz Rubio, O., Cobos García, A., Dias Pereira, C. (2021). Dairy by-products: A review on the valorization of whey and second cheese whey. Foods, 10: 1067

[6]Neethu, M., Bunt, C., Hussain, M., 2015. Comparison of Microbiological and Probiotic Characteristics of Lactobacilli Isolates from Daity FOod Products and Animal Rumen Contens Microorganims 3, 198-212.

[7] Rama, G.R., Kuhn, D., Beux, S., aciel, M.J., Volken de Souz, C.F., 2019. Potential apllications of dairy why for the production of lactic acid bacteira cultures. Int Dairy J.

[8] Rodriguez-Palacios, 1., Staemplfli, H.R., Duffield, T., Weese, J.S., 009. Isolation of bovine intestinal Lactobacillus plantarum and Pediococcus acidilactici with inhibitory activity against Escherichia coli O157 and F5. J. Appl. Mcrobiol. 106, 393-401

 

The BRTA is a consortium that remains a step ahead of future socio-economic challenges worldwide and in the Basque Autonomous Community; it addresses them through research and technological development, thus projecting itself internationally. The BRTA centres collaborate to generate knowledge and transfer it to Basque society and industry so as to make them more innovative and competitive. The BRTA is an alliance of 17 R&D centres and cooperative research centres with the support of the Basque Government, the SPRI and the Chartered Provincial Councils of Araba, Bizkaia and Gipuzkoa.

The post Turning cheese whey into value: a sustainable substrate for probiotic biomass production appeared first on Mapping Ignorance.

Already looking for children’s toys for the holidays? Are you also a big Halloween fan? Well, do we have a  gift for you! Allow us to introduce the present no child could ever love (unless maybe they were possessed by a demon or a big fan of The Nightmare Before Christmas): The Creeping Baby Doll!

This nightmarish 1871 creation is everything you don’t want in a children’s toy. It’s noisy. It moves—seemingly propelled by painted plaster baby arms and legs. And it’s way creepy. 

The mechanical baby doll has two legs, two arms, and a head all made of painted plaster (which is undoubtedly a bit chipped after more than 150 years). These plaster bits are really the only thing that actually look somewhat like a baby. The rest of the doll’s body is made up of brass clockwork. Some sort of dress or outfit would’ve likely covered its brass body back in the day. 

Both the arms and legs are attached to gears that make the plaster limbs move so it looks like the baby doll is crawling (hence, the name—though we would argue there’s perhaps a reason they went with “creeping” instead of “crawling”). The entirety of the toy moves using two toothed wheels hidden under the baby’s body. A flat piece of wood covers the baby’s back to hide the mechanical instruments that make up the baby’s insides.

New York City-based inventor George Pemberton Clarke developed the horrific toy as an improvement to his colleague’s own creeping baby doll. That’s right, there were two! His associate, inventor Robert J. Clay, had filed the patent for his own creeping baby doll on March 14, 1871. Clarke later filed his patent on August 29th of that same year. They really thought this toy would be a hit apparently.

To be fair, there’s a long history of inventors trying to mimic human movement in machines. As far back as ancient Greece, there are stories of human mechanical models dumbfounding awestruck audiences. In the ninth century, Persian alchemist Jabir ibn Hayyan created moving statues. In the 10th century, Chinese engineer Yan Shi (nicknamed the Artificer) created life-size, human-like, moving figurines to the delight of King Mu of Zhou. 

Mechanical automata reached their heyday during the Enlightenment and into the Victorian age. Automated sailing ships decorated tables, mechanical birds sang from gilded boxes, and silver swans floated down peaceful streams.

But even when you take into account the long history of automata, it is hard to look at Clarke’s Creeping Baby Doll and not think it’s a horror movie prop. In fact, it kind of was. 

According to a Boing Boing, the antique toy actually inspired a very obscure 1972 horror film called Miriam: The Wind-Up Killer Doll. The film follows a group of friends who find a vintage crawling baby doll at a garage sale. But, in true horror movie fashion, an evil force possesses the baby doll, and the demonic doll starts killing off the friends one by one. (We didn’t say it was an original scary movie.)

That said, maybe we don’t actually recommend getting your favorite child Clarke’s Creeping Baby Doll. That decision may come back to haunt you.

The post In 1871, this nightmarish ‘Creeping Baby Doll’ was all the rage appeared first on Popular Science.