Researchers converted desert sand into a living material that slows water drainage and remains cohesive underwater. By encouraging microbes to generate microscopic fibers between the sand grains, laboratory experiments showed that these fibers lowered water permeability to roughly one-sixth the level measured in untreated sand. Drawing on the way roots, fungal hyphae, and microbial filaments naturally bind soil particles, scientists at Khalifa University, Empa, and ETH Zurich examined a cellulose-producing bacterium together with two fungal strains.
The bacterium produced a fine mesh that adhered to individual grains and linked them together. After seven days, a treated column of sand approximately 6 centimeters (2.4 inches) high was solid enough to be extracted from its mold and sliced into pieces that stayed intact when submerged. A separate method yielded a still larger reduction in drainage: thin cellulose sheets were grown independently and inserted between successive layers of sand, cutting water permeability by a factor of about 28.
Reduced drainage rates might ultimately help retain moisture closer to plant roots, while the fibers could also stabilize loose surfaces and offer a biodegradable substitute for certain synthetic soil-reinforcement products. Yet a slower rate of water movement does not equate to sixfold greater storage capacity; the measured water-holding ability of the treated sand rose only modestly. The entire demonstration remains confined to the laboratory, where the microbes were supplied with water and nutrients under controlled conditions, and no trials assessed crop growth or long-term persistence in actual desert environments. The subsequent task is to determine whether these microscopic networks can produce durable benefits beyond the controlled setting of the lab.
[Vakeri, S. M., Sinha, A., Greca, L. G., Salim, M. H., Mabrook, G., Ziyan, Z., Dali, M. H. A., AlMarzooqi, F. A., Mettu, S., Nyström, G., & Tardy, B. L. (2025). Living sand: Microbial nanocellulose and chitin-rich mycelia enhance granular material properties. Carbohydrate Polymers, 370, 124361. DOI: 10.1016/j.carbpol.2025.124361]