Abstract EANA2025-62

“Is there life anywhere else besides Earth?” This question is at the forefront of planetary exploration. Among the eight planets, Mars is known to have once had liquid water on its surface in the past. This is evident from the discovery of sedimentary rocks containing riverbeds and rounded gravels. Additionally, analysis of seismic vibrations on Mars by NASA's InSight spacecraft revealed that liquid water accumulated at depths of about 10 to 20 km below the surface. Other findings include a strong magnetic field, a warm and humid climate for an extended period, and various iron and sulfur compounds that provide the elements necessary for life (carbon, hydrogen, oxygen, phosphorus, and sulfur) as well as and energy sources for microbes. These findings make it highly likely that life exists outside of Earth.

Biological cells carry out various life-sustaining reactions, proteins catalyze these reactions. In other words, the presence of proteins is an essential characteristic of living organisms. Proteinaceous amino acids have also been found in many surface samples collected from the asteroid Ryugu, which orbits between Earth and Mars. These findings suggest that if life exists on any celestial body besides Earth, it is highly utilizes proteins. Although, proteins are complex and there are many types, hydrolysis yields 20 types of amino acids that are easy to identify. Therefore, we believe that by analyzing the amino acids obtained by hydrolyzing space samples, we can believe that we can investigate the existence of life.

Since high-concentration hydrochloric acid is typically used to hydrolyze proteins, it may volatilize and corrode the probe if used in a probe exploring for life on Mars. Additionally, returning the sample to Earth would be difficult due to the probe's energy constraints. Therefore, there is a need to develop safer hydrolytic and analytical methods suitable for on-site life exploration must be developed.

The goal of this study is to develop a safe and efficient method of protein hydrolysis using a solid acid catalyst instead of hydrochloric acid. Solid acid catalysts are not only non-corrosive but are also easily separated from the reactants, making them a potentially very innovative method for protein hydrolysis.

Experimental results showed that the hydrolysis of a model protein (bovine serum albumin) and soil samples using the solid acid catalyst TOYOPEARL SP-550C yielded a similar amount of amino acids as hydrochloric acid hydrolysis.

This result indicates that protein hydrolysis using solid acid catalysts is feasible. This achievement is expected to lead to the development of a device that can rapidly analyze extremely small amounts of proteins in the field. This can be installed in planetary probes such as those on Mars, and is is expected to contribute to discovery of extraterrestrial life.