Tag Archives: #wood

How Do Shipworms Eat Wood? (Biology)

New research reveals that we know less about the history-altering shipworm than we thought

Humans have known for over two thousand years that shipworms, a worm-like mollusk, are responsible for damage to wooden boats, docks, dikes and piers. Yet new research from the University of Massachusetts Amherst published in Frontiers in Microbiology reveals that we still don’t know the most basic thing about them: how they eat.

“It’s unbelievable,” says Reuben Shipway, adjunct assistant professor in microbiology at UMass Amherst, research fellow at the Centre for Enzyme Innovation at the University of Portsmouth, UK, and one of the paper’s authors. “The ancient Greeks wrote about them, Christopher Columbus lost his fleet due to what he called ‘the havoc which the worm had wrought,’ and, today, shipworms cause billions of dollars of damage a year.”

Shipworms also play a key role in mangrove forest ecosystems, found throughout the world’s tropical regions, and are responsible for cycling a huge amount of carbon through the web of life. “Yet,” says Shipway, “we still don’t know how they do what they do.”

Part of the problem is that the nutritious part of wood – cellulose – is encased in a thick and extremely difficult-to-digest layer of lignin. “Imagine a really thick, unbreakable eggshell,” says senior author and UMass professor of microbiology, Barry Goodell.

Certain fungi possess enzymes capable of digesting the lignin, and it has long been thought that symbiotic bacteria living in shipworms’ gills also had the enzymes. “We thought that the bacteria were doing the work,” says Goodell, “but we now know they are not.”

Researchers are still trying to figure out what within the shipworm could be responsible for breaking down the lignin. “I combed through the entire genomes of five different species of shipworm,” says Stefanos Stravoravdis, the paper’s lead author and a graduate student in microbiology at UMass, “looking for specific protein groups which create the enzymes that we know are capable of digesting lignin. My search turned up nothing.”

This, however, is not the end of the story, and the team will be publishing more research in the near future that will help unravel the mystery of how shipworms eat wood. “We need to understand this process” says Stravoravdis.

This research was supported by the National Science Foundation; National Institute of Food and Agriculture; U.S. Department of Agriculture; the Center for Agriculture, Food and the Environment; and the UMass Amherst microbiology department.

Featured image: Section of a piling attacked by shipworms in Belfast, Maine. Credit: Barry Goodell.


Reference: Stefanos Stravoravdis et al., “How Do Shipworms Eat Wood? Screening Shipworm Gill Symbiont Genomes for Lignin-Modifying Enzymes”,Front. Microbiol., 12 July 2021 | https://doi.org/10.3389/fmicb.2021.665001


Provided by University of Massachusetts Amherst

Researchers Turn Wood Into Plastic (Engineering)

Plastics are one of the world’s largest polluters, taking hundreds of years to degrade in nature. A research team, led by YSE professor Yuan Yao and Liangbing Hu from the University of Maryland, has created a high-quality bioplastic from wood byproducts that they hope can solve one of the world’s most pressing environmental issues.

Efforts to shift from petrochemical plastics to renewable and biodegradable plastics have proven tricky — the production process can require toxic chemicals and is expensive, and the mechanical strength and water stability is often insufficient. But researchers have made a breakthrough, using wood byproducts, that shows promise for producing more durable and sustainable bioplastics. 

A study published in Nature Sustainability, co-authored by Yuan Yao, assistant professor of industrial ecology and sustainable systems at Yale School of the Environment (YSE), outlines the process of deconstructing the porous matrix of natural wood into a slurry. The researchers say the resulting material shows a high mechanical strength, stability when holding liquids, and UV-light resistance. It can also be recycled or safely biodegraded in the natural environment, and has a lower life-cycle environmental impact when compared with petroleum-based plastics and other biodegradable plastics. 

“There are many people who have tried to develop these kinds of polymers in plastic, but the mechanical strands are not good enough to replace the plastics we currently use, which are made mostly from fossil fuels,” says Yao. “We’ve developed a straightforward and simple manufacturing process that generates biomass-based plastics from wood, but also plastic that delivers good mechanical properties as well.”

To create the slurry mixture, the researchers used a wood powder — a processing residue usually discarded as waste in lumber mills — and deconstructed the loose, porous structure of the powder with a biodegradable and recyclable deep eutectic solvent (DES). The resulting mixture, which features nanoscale entanglement and hydrogen bonding between the regenerated lignin and cellulose micro/nanofibrils, has a high solid content and high viscosity, which can be casted and rolled without breaking.

“We’ve developed a straightforward and simple manufacturing process that generates biomass-based plastics from wood, but also plastic that delivers good mechanical properties as well.”

— Yuan Yao, assistant professor of industrial ecology and sustainable systems.

Yao then led a comprehensive life cycle assessment to test the environmental impacts of the bioplastic against commons plastics. Sheets of the bioplastic were buried in soil, fracturing after two weeks and completely degrading after three months; additionally, researchers say the bioplastic can be broken back down into the slurry by mechanical stirring, which also allows for the DES to be recovered and reused. 

“That, to me, is what really makes this plastic good: It can all be recycled or biodegraded,” says Yao. “We’ve minimized all of the materials and the waste going into nature.”

The bioplastic has numerous applications, says Liangbing Hu, a professor at the Center for Materials Innovation at the University of Maryland and co-author of the paper. It can be molded into a film that can be used in plastic bags and packaging — one of the major uses of plastic and causes of waste production. Hu also says that because the bioplastic can be molded into different shapes, it has potential for use in automobile manufacturing, as well.

One area the research team continues to investigate is the potential impact on forests if the manufacturing of this bioplastic is scaled up. While the process currently uses wood byproducts in manufacturing, the researchers say they are keenly aware that large-scale production could require usage of massive amounts of wood, which could have far-reaching implications on forests, land management, ecosystems and climate change, to name a few.

Yao says the research team has already begun working with a forest ecologist to create forest simulation models, linking the growth cycle of forests with the manufacturing process. She also sees an opportunity to collaborate with people who work in forest-related fields at YSE — an uncommon convenience.

“It’s not often an engineer can walk down the hall and talk to a forester,” says Yao.

Yao, an emerging scholar in the field of industrial ecology, joined the YSE faculty last year. Her research examines the environmental and economic impacts of emerging technologies and industrial processes., integrating interdisciplinary approaches from the fields of industrial ecology, sustainable engineering, and systems modeling to develop techniques that promote more sustainable engineering approaches and policies.


Reference: Xia, Q., Chen, C., Yao, Y. et al. A strong, biodegradable and recyclable lignocellulosic bioplastic. Nat Sustain (2021). https://www.nature.com/articles/s41893-021-00702-w https://doi.org/10.1038/s41893-021-00702-w


Provided by Yale School of Environment

Luminescent Wood Could Light Up Homes Of The Future (Material Science)

The right indoor lighting can help set the mood, from a soft romantic glow to bright, stimulating colors. But some materials used for lighting, such as plastics, are not eco-friendly. Now, researchers reporting in ACS Nano have developed a bio-based, luminescent, water-resistant wood film that could someday be used as cover panels for lamps, displays and laser devices.

When exposed to UV light on the outside, a luminescent wood panel (right) lights up an indoor space (as seen through “windows;” red arrows), whereas a non-luminescent panel (left) does not. ©Adapted from ACS Nano 2020, DOI: 10.1021/acsnano.0c06110

Consumer demand for eco-friendly, renewable materials has driven researchers to investigate wood-based thin films for optical applications. However, many materials developed so far have drawbacks, such as poor mechanical properties, uneven lighting, a lack of water resistance or the need for a petroleum-based polymer matrix. Qiliang Fu, Ingo Burgert and colleagues wanted to develop a luminescent wood film that could overcome these limitations.

The researchers treated balsa wood with a solution to remove lignin and about half of the hemicelluloses, leaving behind a porous scaffold. The team then infused the delignified wood with a solution containing quantum dots — semiconductor nanoparticles that glow in a particular color when struck by ultraviolet (UV) light. After compressing and drying, the researchers applied a hydrophobic coating. The result was a dense, water-resistant wood film with excellent mechanical properties. Under UV light, the quantum dots in the wood emitted and scattered an orange light that spread evenly throughout the film’s surface. The team demonstrated the ability of a luminescent panel to light up the interior of a toy house. Different types of quantum dots could be incorporated into the wood film to create various colors of lighting products, the researchers say.

Provided by American Chemical Society (ACS)

This Simple Software Creates Complex Wooden Joints (Science And Technology)

Wood is considered an attractive construction material for both aesthetic and environmental purposes. Construction of useful wood objects requires complicated structures and ways to connect components together. Researchers created a novel 3D design application to hugely simplify the design process and also provide milling machine instructions to efficiently produce the designed components. The designs do not require nails or glue, meaning items made with this system can be easily assembled, disassembled, reused, repaired or recycled.

A chair designed in Tsugite. Complex interlocking components mean no tools are needed. © Larsson et al.

Carpentry is a practice as ancient as humanity itself. Equal parts art and engineering, it has figuratively and literally shaped the world around us. Yet despite its ubiquity, carpentry is a difficult and time-consuming skill, leading to relatively high prices for hand-crafted wooden items like furniture. For this reason, much wooden furniture around us is often, at least to some degree, made by machines. Some machines can be highly automated and programmed with designs created on computers by human designers. This in itself can be a very technical and creative challenge, out of reach to many, until now.

Researchers from the Department of Creative Informatics at the University of Tokyo have created a 3D design application to create structural wooden components quickly, easily and efficiently. They call it Tsugite, the Japanese word for joinery, and through a simple 3D interface, users with little or no prior experience in either woodworking or 3D design can create designs for functional wooden structures in minutes. These designs can then instruct milling machines to carve the structural components, which users can then piece together without the need for additional tools or adhesives, following on-screen instructions.

Tsugite interface. Tsugite has an intuitive interface to present users with design options. © Larsson et al.

“Our intention was to make the art of joinery available to people without specific experience. When we tested the interface in a user study, people new to 3D modeling not only designed some complex structures, but also enjoyed doing so,” said researcher Maria Larsson. “Tsugite is simple to use as it guides users through the process one step at a time, starting with a gallery of existing designs that can then be modified for different purposes. But more advanced users can jump straight to a manual editing mode for more freeform creativity.”

Tsugite gives users a detailed view of wooden joints represented by what are known as voxels, essentially 3D pixels, in this case small cubes. These voxels can be moved around at one end of a component to be joined; this automatically adjusts the voxels at the end of the corresponding component such that they are guaranteed to fit together tightly without the need for nails or even glue. Two or more components can be joined and the software algorithm will adjust all accordingly. Different colors inform the user about properties of the joints such as how easily they will slide together, or problems such as potential weaknesses.

Something that makes Tsugite unique is that it will factor the fabrication process directly into the designs. This means that milling machines, which have physical limitations such as their degrees of freedom, tool size and so on, are only given designs they are able to create. Something that has plagued users of 3D printers, which share a common ancestry with milling machines, is that software for 3D printers cannot always be sure how the machine itself will behave which can lead to failed prints.

Joint combinations. All seven unique ways that two pieces can be joined in Tsugite. © Larsson et al.

“There is some great research in the field of computer graphics on how to model a wide variety of joint geometries. But that approach often lacks the practical considerations of manufacturing and material properties,” said Larsson. “Conversely, research in the fields of structural engineering and architecture may be very thorough in this regard, but they might only be concerned with a few kinds of joints. We saw the potential to combine the strengths of these approaches to create Tsugite. It can explore a large variety of joints and yet keeps them within realistic physical limits.”

Another advantage of incorporating fabrication limitations into the design process is that Tsugite’s underlying algorithms have an easier time navigating all the different possibilities they could present to users, as those that are physically impossible are simply not given as options. The researchers hope through further refinements and advancements that Tsugite can be scaled up to design not just furniture and small structures, but also entire buildings.

“According to the U.N., the building and construction industry is responsible for almost 40% of worldwide carbon dioxide emissions. Wood is perhaps the only natural and renewable building material that we have, and efficient joinery can add further sustainability benefits,” said Larsson. “When connecting timbers with joinery, as opposed to metal fixings, for example, it reduces mixing materials. This is good for sorting and recycling. Also, unglued joints can be taken apart without destroying building components. This opens up the possibility for buildings to be disassembled and reassembled elsewhere. Or for defective parts to be replaced. This flexibility of reuse and repair adds sustainability benefits to wood.”

References: Maria Larsson, Hironori Yoshida, Nobuyuki Umetani, and Takeo Igarashi, “Tsugite: Interactive Design and Fabrication of Wood Joints,” Proceedings of the 32nd Annual ACM Symposium on User Interface Software and Technology: October 21, 2020, doi:10.1145/3379337.3415899. Link: http://ma-la.com/Tsugite_UIST20.pdf

Provided by University of Tokyo