Scientists at the University of Houston may have taken a big step toward solving one of the world’s most pressing environmental problems.
They’ve engineered sheets of bacterial cellulose (essentially an eco-friendly material grown by bacteria) to behave like plastic. Strong, transparent, flexible, and biodegradable, these sheets can be used to make everything from packaging and water bottles to electronic components and medical bandages. And remarkably, they’re made by guiding bacteria to build the material themselves, one nanoscale strand at a time.
“We envision these strong, multifunctional and eco-friendly bacterial cellulose sheets becoming ubiquitous, replacing plastics in various industries and helping mitigate environmental damage,” said Maksud Rahman, an assistant professor at the University of Houston and senior author of the new study, published in Nature Communications.
Microbial Farming
Bacterial cellulose is a well-known biopolymer produced by certain microbes like Novacetimonas hansenii, prized for its purity, strength, and biodegradability. But in its natural form, it’s a tangled mess as its nanofibers are randomly oriented, like spaghetti thrown on a plate. That randomness affects the material’s mechanical properties, and not in a desirable way.
So, Rahman and his team devised a way to guide the bacteria into forming orderly structures, much like spinning silk. Their solution was a rotating bioreactor that gently spins a fluid-filled tube containing oxygen-loving bacteria and nutrients.
Inside this rotating cylinder, the bacteria are nudged by the circular flow of fluid to move in consistent paths. As they swim, they secrete cellulose in aligned, parallel threads that accumulate on the oxygen-permeable walls of the device.
“We’re essentially guiding the bacteria to behave with purpose,” Rahman said. “Rather than moving randomly, we direct their motion, so they produce cellulose in an organized way.”
Stronger Than Many Plastics
The result is a sheet of material that’s not only biodegradable but extraordinarily robust. According to the study, these aligned cellulose sheets achieved a tensile strength of 393 megapascals, which is comparable to some metals and significantly higher than most plastics.
For comparison, that’s more than twice as strong as regular bacterial cellulose made by static fermentation. It’s also more than double the strength of aligned cellulose sheets made using post-processing techniques like stretching, without requiring any of those extra steps.
“We report a simple, single-step and scalable bottom-up strategy,” said M.A.S.R. Saadi, the study’s lead author and a doctoral student at Rice University. “The resulting bacterial cellulose sheets display high tensile strength, flexibility, foldability, optical transparency, and long-term mechanical stability.”
In stress tests, the new material resisted cracking even after being folded into an origami airplane. It maintained its shape and strength even after 10,000 cycles of mechanical loading.
And unlike many bioplastics that trade strength for biodegradability, this cellulose doesn’t compromise. “This simultaneous enhancement of both strength and toughness is noteworthy,” the study notes, “as these properties are typically considered mutually exclusive in materials engineering.”
Nanotech Gives Cellulose a New Edge
To give the material even more versatility, the team experimented with adding hexagonal boron nitride nanosheets—nanoscopic flakes of a ceramic material known for its exceptional thermal conductivity and strength.
They simply mixed the flakes into the bacteria’s growth media. The rotation of the bioreactor helped keep the particles suspended and well-distributed. As the bacteria secreted cellulose, the boron nitride nanosheets became embedded within the growing structure, creating a hybrid material with enhanced capabilities.
These bacterial cellulose-boron nitride (BCBN) sheets were even stronger than the plain aligned cellulose, reaching tensile strengths of up to 451 megapascals. They also dispersed heat far more effectively—cooling down three times faster than their unenhanced counterparts when exposed to a laser beam.
“This scalable, single-step bio-fabrication approach… would pave the way towards applications in structural materials, thermal management, packaging, textiles, green electronics and energy storage,” Rahman said.
Previous attempts to align cellulose nanofibers have relied on stretching, electromagnetic fields, or molds. Many of these methods damage the structure, require multiple steps, or limit scalability. What Rahman’s team developed is different: it’s cheap, reproducible, and continuous.
The team’s method also allows for in-situ integration of other nanomaterials—without disrupting the network or requiring extra solvents or binders. This opens the door to smart packaging, conductive textiles, and bioelectronics, all made with the same basic process.
The Bigger Picture
Plastic pollution is one of the defining environmental issues of our time. Plastic production exceeds 400 million metric tons per year, and most of it ends up in landfills or the ocean. Biodegradable plastics exist, but many still require industrial composting, and few can match the durability or versatility of petroleum-based plastic.
What makes bacterial cellulose compelling is that it’s already biodegradable in natural environments, and it doesn’t rely on fossil fuels. And now, with the added strength and flexibility from Rahman’s method, it might finally be ready for prime time.
Still, questions remain. The production yield, for instance, is relatively modest—around 7.5 milligrams per day in the current setup. Scaling it to industrial volumes will require further optimization.
But the system is simple by design. The rotating bioreactor is rather affordable and doesn’t demand specialized conditions or expensive inputs. In theory, it could be adapted to work in resource-limited settings or integrated into circular manufacturing systems.
If the team’s vision holds, the plastic bottle of tomorrow might not come from an oil refinery or recycling plant, but from a tank of spinning bacteria.
