Astrobiologists in Germany are developing a novel testing device that may encourage inactive **alien microbes** to come forward. The core element of this device is **L-serine**, a widely available **amino acid** found in **human blood**.

“L-serine, the specific amino acid we utilized, […] we can synthesize it in our own bodies,” stated Max Riekeles, a researcher engaged in the creation of the alien-detecting device, during an interview with *Mashable*.

L-serine is also prevalent in the oceans on Earth, particularly in the extreme conditions found near **deep-sea hydrothermal vents**, where life flourishes without the need for photosynthesis. **NASA** scientists have even identified L-serine and other “proteinogenic” amino acids, crucial for the synthesis of proteins, **within meteorites**. These discoveries have prompted scientists to consider whether amino acids from outer space could have contributed to the **evolution of life** in other parts of the cosmos.

“It might offer a straightforward approach to searching for life on upcoming **Mars** missions,” Riekeles said, who has a background as an aerospace engineer from the Technical University of Berlin and currently specializes in research related to extraterrestrial biosignatures.

Nevertheless, he recognized the pivotal question that persists: “Did life ever exist there?”

### Utilizing Microbial Movement for Life Detection

Riekeles and his team formulated their device based on **chemotaxis**, a mechanism where microbes, including **bacteria** and archaea, move in reaction to chemical cues.

**Years of investigation** have indicated that numerous microorganisms are naturally attracted to **higher levels of L-serine**. This revelation inspired the team to invent a testing kit featuring two chambers divided by a thin, semi-permeable membrane. One chamber would house a sample from an extraterrestrial environment, while the other—observed via video—would contain a concentrated L-serine solution.

The concept of examining microbes through their movement can be traced back to the 17th century when Antonie van Leeuwenhoek first recorded microscopic organisms. However, Riekeles emphasized that current advancements in technology, big data, and machine learning have revitalized this classical method, enhancing its efficacy significantly.

### Evaluating the Device on Extremophiles

In their recent research, published in *Frontiers in Astronomy and Space Sciences*, Riekeles and his team assessed the device using three **extremophile** species—microorganisms that flourish in the most extreme environments on Earth. These species were selected to imitate the types of microbes that could potentially endure on **Mars** or the icy moons of **Jupiter**, like **Europa**, **Ganymede**, and **Callisto**.

One such microbe, *Pseudoalteromonas haloplanktis* (or *P. halo*), was sourced from Antarctic waters and is capable of surviving in **subzero temperatures**. “It thrives in extremely cold conditions, for instance,” Riekeles elaborated, “and it’s also adept at withstanding salty environments.”

This is particularly significant for Mars, where researchers suspect the surface may harbor substantial quantities of salt.

The team also examined *Bacillus subtilis*, a bacterium that can withstand **boiling conditions**, and *Haloferax volcanii*, an archaeon located in the **Dead Sea** that can endure extreme **radiation exposure**—a feature that renders it comparable to **theoretical Martian microbes**.

“It’s not just salt tolerant,” Riekeles emphasized. “If it’s in an environment without salt, it won’t survive.”

### Encouraging Results and Prospective Challenges

All three microorganisms in the investigation swiftly moved from the sample chamber to the test chamber with L-serine. Within an hour, each species’ density surged by **200%**, with *B. subtilis* achieving **400%** when the concentration of L-serine was increased.

“We also experimented with other substances, such as glucose and ribose,” Riekeles mentioned, “but for these three organisms, L-serine proved to be the most effective.”

Despite these encouraging outcomes, planetary habitability specialist Dirk Schulze-Makuch, who collaborated on the initiative, warned that significant hurdles remain before the device can be utilized on Mars.

“One major issue,” he wrote for **Big Think**, “is locating a site that is reachable by a lander but where liquid water might also be present.”

Potential landing sites could include the **Southern Highlands of Mars**, the **floor of Valles Marineris**, or **caves**, where atmospheric pressure may be adequate to sustain **liquid (salty) water**—a vital element for life.

If it proves successful, this straightforward yet groundbreaking device could provide a new method for the search for extraterrestrial life, drawing us nearer to solving one of humanity’s greatest mysteries: **Are we alone in the universe?**