This is a microbe's world, not a human one, and compared to us, their biological machinations are bonkers. Some snooze in massive crystals, some use irradiated sulfur-rich minerals to live in deoxygenated darkness, and others, as noted by ScienceMag, can quite literally manufacture fuel.
Back in 1986, Swiss microbiologists uncovered a bacterium within Lake Zurich, and found that it synthesizes toluene, a type of hydrocarbon. Now, as reported in Nature Chemical Biology, a team led by the Lawrence Berkeley National Laboratory has worked out how this microbial alchemy takes place.
Toluene is used as an octane booster in gasoline, but that’s not its only use; it’s also a solvent found in paint thinners, glues, varnishes, rubber cement, and it's even involved in the making of TNT. It’s also used by some as a form of recreational drug, but considering it can be neurotoxic, this is inadvisable.
Humanity first synthesized toluene in the early-to-mid 19th century, but it appears that bacteria may have pipped us to the post. Although the bacterial genus found in Lake Zurich, Tolumonas auensis, was the original microbial maestro in this regard, it’s not the only one that has this ability – Clostridium aerofoetidum has the skills too.
Sadly, no-one’s been able to figure out how any of them manage to proceed with this “biochemically challenging reaction”, as the multidisciplinary team note in their paper.
They explain that attempts to use these bacteria to “reproduce toluene biosynthesis” in laboratory conditions have been unsuccessful, and although they suspected a particular enzyme was playing a key role, only indirect evidence was found to date.
Leaving Lake Zurich behind, the new team of researchers had a peek inside Jewel Lake, in a park in Berkeley. Finding samples of toluene in the lake, and a nearby sewage treatment plant, they ran samples through a metagenomic analysis, hoping to identify any biochemical componentry that could help explain where it was coming from.