Inside The Lab Growing Mutant Bacteria To Terraform Earth

BARCELONA, Spain — The microbes have assembled themselves into the rough shape of an open hand, reaching out from fluid at the bottom of the bottle. A dozen such containers sit side by side in the beachfront Barcelona Biomedical Research Park, each containing translucent, moss-colored filaments that cling to the glass. But I’m stuck staring at this one sample that has built something so solid-looking out of these weightless strands — its thick wrist supporting an upturned palm that dissolves, where the fingers should be, into curls of soft hair.

This is not normal behavior for these bacteria, explains Núria Conde Pueyo, a post-doctoral researcher at the European Molecular Biology Laboratory. Microcoleus vaginatus is a photosynthetic bacterium that lives in dry soils and, when grown in test tubes, tends to just float around in its nutrient-rich liquid. No one in this lab has seen it create this kind of elaborate architecture. Conde Pueyo shrugs. “We are trying to figure out why.”

The answer most likely lies in the recent regime of torture this lab has overseen. Three years ago, these bacteria were living in Alicante, an area on Spain’s Mediterranean coast, in a patch of arid dirt that’s turning into a desert. From these unpromising beginnings, Conde Pueyo subjected the soil samples to a process known as hardening, a sort of trial by fire to replicate the tough conditions these microbes are expected to face as our planet’s climate changes. They were made “very dry, very hot,” she explains, and subjected to “a lot of ultraviolet, some cycles that were very harsh.” She has taken to the job of tormentor with apparent glee: “I mistreat that soil a lot,” she smiles.

So far, Conde Pueyo has whittled down an initial 70 species of photosynthetic bacteria from the sample to just 16, including the M. vaginatus now cultured in the flasks. “They are the survivors,” she says. But the process doesn’t just sort the microbial men from the boys; the bacteria become tougher through…