Scientists are combining traditional materials with bacteria, algae, and fungi to create bio-materials that can acquire practical properties through microbial metabolism. “For example, the ability to absorb carbon dioxide from the air through photosynthesis,” says Mark Tibbitt, a professor of macromolecular engineering at ETH Zurich.
Currently, the interdisciplinary team led by Tibbitt has turned this vision into reality. They have stably integrated cyanobacteria, a type of photosynthetic bacteria, into printable gels, developing a living, growing material that actively removes carbon from the air. The related research findings were recently published in Nature Communications.
“Plankton” showcases large objects made from photosynthetic structures. Image source: Valentina Mori
This material can be shaped through 3D printing and can grow using only sunlight, artificial seawater, and readily available nutrients. “As a building material, it may eventually be able to directly sequester carbon dioxide within structures,” Tibbitt says.
The uniqueness of this material lies in its ability to absorb carbon dioxide far exceeding that fixed through organic growth. “Because this material can store carbon not only in biomass form but also in mineral form—this is the special property of cyanobacteria,” Tibbitt explains.
PhD student Cui Yifan (phonetic) from Tibbitt’s research group explains, “Cyanobacteria are one of the oldest life forms on Earth. They have extremely high photosynthetic efficiency, converting carbon dioxide and water into biomass even in very low light conditions.” At the same time, these bacteria alter the chemical environment outside the cells through photosynthesis, promoting the precipitation of carbonates (such as limestone). These minerals become another carbon sink and can sequester carbon in a more stable form compared to biomass.
“We have deliberately enhanced this property in the material,” Cui Yifan says, noting that the deposition of minerals within the material increases its mechanical strength, causing the initially soft structure to gradually harden.
Laboratory tests show that this material can continuously sequester carbon for 400 days, fixing about 26 milligrams of carbon dioxide per gram of material, with most of it stored in mineral form, far exceeding the carbon fixation efficiency of many biological methods.
The matrix that carries living cells is a highly water-retentive gel made of cross-linked polymers. The polymer network designed by Tibbitt’s team can transmit light, carbon dioxide, water, and nutrients while allowing cells to be evenly distributed within the material.
To ensure the long-term survival and efficiency of cyanobacteria, researchers also optimized the geometric structure through 3D printing to increase surface area, enhance light transmission, and promote nutrient flow. “The structure we designed allows light to pass through and can passively distribute nutrient solutions through capillary action,” notes Dalia Dranseike, co-first author of the paper, adding that the encapsulated cyanobacteria can maintain high activity for over a year.
The researchers believe that this low-energy, environmentally friendly active material can complement existing chemical carbon fixation processes. “In the future, we hope to explore how to use it as a coating for building facades, continuously sequestering carbon throughout the lifecycle of the building,” Tibbitt says.
Although the road ahead is long, peers in the construction field have already begun experimental applications. Driven by ETH Zurich PhD student Andrea Shin Ling, this foundational research has made its way to the 19th Venice International Architecture Biennale. “The most challenging part is scaling up the production process from laboratory size to building size,” says the architect and bio-designer who also participated in the research.
Under the guidance of Professor Benjamin Dillenburger in digital building technology at ETH Zurich, Ling developed a bio-manufacturing platform capable of printing active structures containing functional cyanobacteria at building scale. An installation named “Plankton” exhibited at the Canadian Pavilion of the Venice International Architecture Biennale features two tree-like pieces made from printed active components, each reaching about 3 meters in height. With the help of cyanobacteria, each piece can sequester 18 kilograms of carbon annually, equivalent to the carbon fixation of a 20-year-old pine tree in temperate regions.
“This installation is an experiment—we transformed the Canadian Pavilion to provide ample light, humidity, and temperature, and then observed the growth status of the cyanobacteria,” Ling explains.
Planning and Production
Source: China Science Daily
Editor: Yinuo
Reviewers: Xu Lai, Lin Lin
Images in this article are from copyright stock images
Reproducing this content may lead to copyright disputesFor original text and images, please reply “Reprint” in the background
Light Up the “Recommendation”
Let’s Gain Knowledge Together!
