Key facts
- A new building material for Mars is made from engineered yeast, gelatin, and sand.
- The material hardens in cold temperatures and can be reused up to four times.
- Engineered yeast cells, modified with genes from mussels, create a stronger glue.
- The material has a compressive strength of about 1,740 psi (12 MPa), similar to low-grade concrete.
- The mixture is printed at 99°F (37°C) and hardens via freeze-drying in low pressure and cold.
Scientists in Hong Kong have developed a novel building material for potential use on Mars, utilizing genetically engineered yeast, gelatin, and sand. This approach offers a low-cost and energy-efficient alternative to transporting construction materials from Earth or melting Martian soil.
The material begins as a wet mixture where sand provides bulk, and a warm glue of gelatin and yeast cells coats the grains. This mixture is then subjected to conditions simulating Mars: -55°C (-67°F) and roughly one ten-thousandth of Earth's air pressure. In this environment, the water undergoes freeze-drying, turning directly from ice to vapor without melting, which hardens the material.
The engineered yeast, Saccharomyces cerevisiae, was modified with genes that cause it to grow a coat of sticky proteins, similar to those mussels use to adhere to wet surfaces. This modification significantly strengthened the glue, increasing its load-carrying capacity by 170 percent compared to gelatin alone. Tests showed that joints made with the engineered cells tore through the middle, indicating a stronger bond with the sand than the glue itself.
The resulting material is stiff and porous, with a lightweight structure due to its holes. It achieved a mean compressive strength of about 1,740 pounds per square inch (12 megapascals), comparable to low-grade concrete, and a bending strength of approximately 870 pounds per square inch (6 megapascals). The team successfully printed a 1-inch tall tower under simulated Martian conditions of -30°C (-22°F) and 0.01 atmospheres.