The microscopic world is a true nursery capable of miraculous things that can go weirder beyond belief. It happened multiple times for scientists, so there’s a good chance that things won’t change soon. One thing is for sure, though, nature is awesome and it appears to have endless possibilities, and not only when it comes to the “big stuff.”
The first manganese-fueled bacteria was recently discovered by several scientists, and the best part about their finding is that they only had to look as far as the office sink. Can you believe it? Yes, We’re not joking here, this bacteria is using metal manganese for growing.
“It’s definitely an interesting story about serendipity,” says Jared Leadbetter, an environmental microbiologist at Caltech. He and Hang Yu, also an environmental microbiologist at Caltech, report their fortuitous find in the July 16 Nature.
Jared Leadbetter was working with a pink compound called manganese carbonate in a glass jar. After finishing his work with the manganese carbonate, he couldn’t properly clean the jar, so he decided to fill it with tap water and let it to soak. Here comes the interesting part. 10 weeks later (after an out-of-town work trip), when he returned to the office, the substance from the jar had turned into a dark, crusty material and he discovered around 70 bacterial species in that jar.
“I thought, ‘What is that?'” said Leadbeater. “I started to wonder if long-sought-after microbes might be responsible,” Leadbeater explained, “so we systematically performed tests to figure that out.”
And when you think that it all begun with a jar… However, Leadbetter’s discovery wasn’t quite a surprise, considering that scientists suspected that bacteria could use manganese as e fuel to grow. Researchers discovered over a century ago that bacteria could borrow electrons from chemical elements like nitrogen, sulfur, iron, and of course, manganese.
It was also believed that bacteria even had the power to use these electrons just as we, humans, use electrons from carbohydrates for energy in our diets, to fuel growth. Nonetheless, there wasn’t any evidence to support this theory and no identified bacteria that could turn manganese into energy, until now.
“These are the first bacteria found to use manganese as their source of fuel,” explained Leadbetter, although such microbes were predicted to exist over a century ago.
When bacteria borrow electrons from manganese, they turn the metal into a dark material called manganese oxide, which can be found all over our planet (from deposits in Earth’s crust to the seafloor to drinking water). And, fortunately, it all happened in Leadbetter’s glass jar.
“Maybe I better not pour this down the sink,” he thought, as he wondered if the bacteria he had in his jar might be the first manganese-fueled species.
The scientists discovered around 70 species of bacteria in that jar, which they assumed it came from the tap water. They decided to isolate two bacterial species that generate manganese oxide when put together. Additionally, these bacterial species multiplied rapidly when they received manganese carbonate. As the bacterial population got bigger and bigger, the level of manganese oxide production increased too, implying that the bacteria were using manganese as fuel.
“We isolated [the betaproteobacterium] from disrupted oxides as single colonies… but this species does not oxidize MnCO3 alone. Either the Nitropirae is solely responsible for Mn(II) oxidation or the activity is consortial,” the team writes in a new study.
Researchers named the freshly identified species ‘Candidatus Manganitrophus noduliformans’ and Ramlibacter lithotrophicus. However, they have no other relevant information about this as they don’t know the exact role of each species. Maybe both species can generate energy from the manganese or one of the two could be the main driver, but again, there’s no clear evidence yet to support this theory.
Their discovery, however, could help researchers manage manganese oxide that pollutes drinking water, says Amy Pruden, an environmental scientist at Virginia Tech in Blacksburg who was not involved in the study. “Now that we have an idea of who the manganese oxidizers are, we can start looking for them in drinking water systems, and maybe we can find better controls.”
“There is a whole set of environmental engineering literature on drinking-water-distribution systems getting clogged by manganese oxides,” said Leadbetter.
“But how and for what reason such material is generated there has remained an enigma. Clearly, many scientists have considered that bacteria using manganese for energy might be responsible, but evidence supporting this idea was not available until now.”
Moreover, Jared Leadbetter believes that similar bacteria might also be accountable for nodules of manganese oxide on the ocean floor, which were first noticed in the 1870s, and at that time, they have amazed scientists. He wants to take a look out there and other places for more species of bacteria that use manganese as a fuel for growth.
“Let’s see if we can find these organisms in other environments,” Leadbetter says. “Not just my sink.”
