Sheets of bacterial cellulose slowed water through sand 28-fold in a lab test with three replicates
Researchers at Khalifa University, Empa and ETH Zurich report that bacterial cellulose sheets cut water permeability in sand about 28-fold in lab tests. Fibers grown among the grains gave about a sixfold cut, and crop growth was not tested.
The Scientist · Science desk
In laboratory tests, a bacterial cellulose sheet placed between sand layers cut water permeability about 28-fold compared with untreated sand, while fibers grown directly inside the sand cut it about six-fold.
Permeability cut vs untreated sand, laboratory tests In -fold cut
| Item | Value | Claim |
|---|---|---|
| Inserted cellulose sheet, about | 28 -fold cut | 3 |
| Fibers grown in the sand, about | 6 -fold cut | 7 |
What happened
- The team grew a cellulose-producing bacterium, Komagataeibacter medellinensis, and two strains of the fungus Schizophyllum commune in sand.
- Permeability was measured by timing water draining from sand-filled tubes, comparing untreated sand, in-sand fibers and an inserted sheet, with three replicate samples per group.
- Bacterial samples were stronger than fungal ones: a column about 6 centimeters tall held together within seven days, while some fungal samples broke during removal or cutting.
- Water holding in sand with in-sand fibers rose from about 20.2 percent to 25.5 percent, an increase the scientists call slight.
Why it matters
- What doesn't add up contradiction ScienceAlert calls the six-fold result a water-loss cut in one passage and a permeability cut in another, and the test timed drainage, so it does not show that treated sand holds water longer.
- What it limits constraint Water a root can reach is what matters for farming, and the measured rise in holding capacity was about 26 percent in relative terms, small beside the flow reductions.
- What's now possible capability If the binding holds outdoors, the team's suggestion is a biodegradable alternative to some synthetic soil stabilizers, though the wind-erosion benefit is a hypothesis until dust is measured.
The 28-fold cut from the cellulose sheets [3] comes from groups of three samples [6]. That shows a large gap between treated and untreated sand and says little about variation across batches or sand types. Put as a fraction, the sheet left the sand with about 3.6 percent of its untreated permeability [14]. Fibers grown among the grains reached about six-fold [7].
ScienceAlert's account describes that six-fold result two ways. One passage says the "living sand" tests showed it "could cut water loss by six times" [2]. A later passage gives the same six-fold figure as a drop in permeability, meaning how fast water passes through [7]. The measurement described is the second one. Timing a tube's drainage shows how quickly water leaves the sand, and it is not an evaporation measure.
The thing this doesn't tell you is how much water a plant can use. For the in-sand fibers, the holding-capacity gain was 5.3 percentage points, about 26 percent in relative terms [15]. That is small beside the flow reductions.
We'd expect a layer that slows water leaving to slow water arriving as well. Irrigation would have to be designed around that.
The strength evidence for the sheets is a demonstration with a 10-kilogram load: an untreated sand cube collapsed much more than one reinforced with cellulose sheets [10]. Gustav Nystrom, who heads Empa's Cellulose and Wood Materials laboratory, was cautious about what the material does. "This approach allows us to introduce organic matter and water into the sand and stabilize it somewhat," he said [17].
The sand came from dunes near Al Ain in the UAE, with standardized laboratory sand for some strength tests, and it was sterilized before the microbes and nutrient solutions went in [5]. The microbes then received water and nutrients under controlled conditions, and their growth depended on oxygen [11]. In the bacterial column, growth varied with height, and the upper section came out far weaker than the lower one [11]. Nobody grew crops in the treated sand, and the work did not show how long the material would hold up in desert conditions [12]. The team suggests stronger links between grains might limit wind erosion, but dust emissions were not measured [16].
The paper in Carbohydrate Polymers carries a competing interests statement in which three authors disclose a pending patent application: Blaise Tardy, M-Haidar A. Dali and Mohamed Hamid Salim [1][13].
What to watch
- Greenhouse or field trials that grow crops in treated sand, since none were run here.
- Wind-tunnel or dust-emission measurements, which would test the erosion benefit the team only suggests.
- Durability tests in desert conditions, including whether the weak top section of the bacterial column can be fixed.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence55
- Adoption
- Insufficient
- Hype gap+20
- Incentives35
- Confidence60
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
The study was published in Carbohydrate Polymers and involved researchers at Khalifa University in the United Arab Emirates, Switzerland's Empa research institute, and ETH Zurich.
- [2]
Growing microbes directly in sand created a material the researchers call "living sand," which tests showed could cut water loss by six times.
- [3]
Thin sheets of bacterial cellulose placed between sand layers reduced water permeability about 28-fold in laboratory tests.
- [4]
The researchers used a cellulose-producing bacterium, Komagataeibacter medellinensis, and two strains of the fungus Schizophyllum commune, which belong to the same species but have different growth characteristics.
- [5]
The study included sand collected from dunes near Al Ain in the UAE, along with standardized laboratory sand for certain strength tests, and researchers sterilized the sand before adding the microbes and nutrient solutions.
- [6]
To test permeability, the researchers poured water into sand-filled tubes and timed how fast it drained out of the bottom, comparing untreated sand, sand with fibers grown among the grains, and sand with a separately grown cellulose sheet. Each group had three replicate samples.
- [7]
The inserted sheet cut permeability to roughly one twenty-eighth of the untreated sand's value, while fibers grown directly inside the sand reduced it about six-fold.
- [8]
For sand containing fibers grown directly among the grains, the water-holding measurement rose from about 20.2 percent to 25.5 percent, an increase the scientists describe as slight.
- [9]
The bacterial treatment produced stronger samples than the fungi: within seven days a sand column about 6 centimeters tall held together well enough to be removed from its mold and cut, and the pieces stayed intact in water. Fungal samples were more fragile, and some broke apart during removal from the molds or when cut after drying.
- [10]
In a demonstration using a 10-kilogram load, an untreated sand cube collapsed much more than a cube reinforced with cellulose sheets.
- [11]
The work is a laboratory study: the microbes received water and nutrients under controlled conditions and their growth required oxygen. Growth was uneven along the bacterial sand column, and the top section was much weaker than the bottom.
- [12]
The experiments did not test crop growth or establish how long the material would survive desert conditions.
- [13]
Three researchers, Blaise Tardy, M-Haidar A. Dali, and Mohamed Hamid Salim, disclosed a pending patent application in the paper's competing interests statement.
- [14]
A permeability of one twenty-eighth of the untreated value is about 3.6 percent of it.
- [15]
The holding-capacity rise from about 20.2 percent to 25.5 percent is 5.3 percentage points, about 26 percent in relative terms.
- [16]
The team suggests microbial fibers could provide biodegradable alternatives to some synthetic materials used to stabilize soil, and stronger connections between grains might help limit wind erosion, although the experiments did not measure dust emissions.
- [17]
"This approach allows us to introduce organic matter and water into the sand and stabilize it somewhat," said Gustav Nystrom, who heads Empa's Cellulose and Wood Materials laboratory.
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Sources
1 independent publisher whose own reporting we read for this story.
- sciencealert.comScientists Find a Way to Turn Desert Sand Into 'Living Sand' That Holds Water Six Times Longer
1 article · October 15, 2026
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