Theory and observation for the search for life on exoplanets via atmospheric ‘biosignature gases’ is accelerating, motivated by the capabilities of the next generation of space- and ground-based telescopes. The most observationally accessible rocky planet atmospheres are those dominated by molecular hydrogen gas, because the low density of H₂ gas leads to an expansive atmosphere. The capability of life to withstand such exotic environments, however, has not been tested in this context. We demonstrate that single-celled microorganisms (Escherichia coli and yeast) that normally do not inhabit H₂-dominated environments can survive and grow in a 100% H₂ atmosphere. We also describe the astonishing diversity of dozens of different gases produced by E. coli, including many already proposed as potential biosignature gases (for example, nitrous oxide, ammonia, methanethiol, dimethylsulfide, carbonyl sulfide and isoprene). This work demonstrates the utility of laboratory experiments to better identify which kinds of alien environments can host some form of possibly detectable life.

下一代天基和天基望远镜的功能推动了通过大气“生物特征气体”在系外行星上寻找生命的理论和观察的发展。观察最多的岩石行星大气是分子氢占主导的大气，因为H ₂气体的低密度会导致膨胀的大气。然而，尚未在这种情况下测试生活承受这种异国环境的能力。我们证明了通常不居住在以H ₂为主的环境中的单细胞微生物（大肠杆菌和酵母菌）可以在100％H _2中存活并生长大气层。我们还描述了由大肠杆菌产生的数十种不同气体的惊人多样性，其中包括许多已经被提议作为潜在生物特征气体（例如，一氧化二氮，氨，甲硫醇，二甲基硫醚，羰基硫和异戊二烯）。这项工作证明了实验室实验的效用，可以更好地识别哪些种类的外星环境可以拥有某种形式的可能被发现的生命。