Kombucha Cultures Make Excellent Sustainable Water Filters, Study Finds (arstechnica.com) 15
Long-time Slashdot reader shoor shares a report from Ars Technica: The refreshing kombucha tea that's all the rage these days among certain global demographics might also hold the key to affordable, environmentally sustainable living membranes for water filtration, according to a recent paper published in the American Chemical Society journal ACS ES&T Water. Experiments by researchers at Montana Technological University (MTU) and Arizona State University (ASU) showed that membranes grown from kombucha cultures were better at preventing the formation of biofilms -- a significant challenge in water filtration -- than current commercial membranes.
Co-author Katherine Zodrow, an environmental engineer at MTU, led an earlier 2020 study demonstrating the feasibility of making sustainable living filtration membranes (LFMs) out of a bacterial cellulose network and the native microorganisms of a kombucha SCOBY (symbiotic culture of bacteria and yeast) culture. Zodrow and her new collaborators made their membranes for this latest round of experiments the same way: by placing a SCOBY in a growth solution of sugar, black tea, and distilled white vinegar dissolved in deionized water. The researchers then placed the mixture in a temperature-controlled room for 10-12 days until a thick membrane formed on the mixture's surface. The grown membranes were stored in deionized water and used in experiments within eight days. The 20 liters of raw water samples for the experiments were taken from the three drinking water treatment plants in Butte, Montana: Basin Creek Reservoir, Moulton Reservoir, and Big Hole River. The water samples were then pretreated in accordance with standard practices at each plant.
Both the LFMs and polymer-based filters, the researchers discovered, became clogged over time, causing them to flow and filter more slowly. The LFMs used in the experiments, however, showed between 19 and 40 percent better performance than their commercial counterparts on that score. The SCOBY-based LFMs were also more resistant to befouling. While biofilms eventually formed, fewer microorganisms were found in those films. Zodrow et al. sequenced the DNA of any bacteria and fungi in the SCOBY-based membrane and found that 97 percent of the bacteria present belonged to the genus Acetobacter. This is not surprising, since it's also the dominant bacteria in kombucha, but it may explain why the LFMs performed so well with regard to biofilms. As the name implies, a defining characteristic of this genus is the ability to oxidize organic carbon sources like sucrose, glucose, and ethanol into acetic acid, which is known for its antimicrobial properties. Acetobacter has also been shown to reduce or even remove biofilms, in keeping with the results of Zodrow et al.'s experiments.
Co-author Katherine Zodrow, an environmental engineer at MTU, led an earlier 2020 study demonstrating the feasibility of making sustainable living filtration membranes (LFMs) out of a bacterial cellulose network and the native microorganisms of a kombucha SCOBY (symbiotic culture of bacteria and yeast) culture. Zodrow and her new collaborators made their membranes for this latest round of experiments the same way: by placing a SCOBY in a growth solution of sugar, black tea, and distilled white vinegar dissolved in deionized water. The researchers then placed the mixture in a temperature-controlled room for 10-12 days until a thick membrane formed on the mixture's surface. The grown membranes were stored in deionized water and used in experiments within eight days. The 20 liters of raw water samples for the experiments were taken from the three drinking water treatment plants in Butte, Montana: Basin Creek Reservoir, Moulton Reservoir, and Big Hole River. The water samples were then pretreated in accordance with standard practices at each plant.
Both the LFMs and polymer-based filters, the researchers discovered, became clogged over time, causing them to flow and filter more slowly. The LFMs used in the experiments, however, showed between 19 and 40 percent better performance than their commercial counterparts on that score. The SCOBY-based LFMs were also more resistant to befouling. While biofilms eventually formed, fewer microorganisms were found in those films. Zodrow et al. sequenced the DNA of any bacteria and fungi in the SCOBY-based membrane and found that 97 percent of the bacteria present belonged to the genus Acetobacter. This is not surprising, since it's also the dominant bacteria in kombucha, but it may explain why the LFMs performed so well with regard to biofilms. As the name implies, a defining characteristic of this genus is the ability to oxidize organic carbon sources like sucrose, glucose, and ethanol into acetic acid, which is known for its antimicrobial properties. Acetobacter has also been shown to reduce or even remove biofilms, in keeping with the results of Zodrow et al.'s experiments.
Next obvious step (Score:2)
Now they can test adding the komucha bacteria film to the face of the other filter screens.
Vinegar pee water? (Score:5, Funny)
Re:Vinegar pee water? (Score:5, Interesting)
If kombucha isn't to your taste, maybe small beer would be more to your liking.
For all of history up until the development of a global ice trade in the 19th Century, the preferred method for making stored foods and drink bacteriologically safe was fermentation with a benign organism. Every culture -- literally *every last one* -- has a rich, pre-industrial tradition of fermented foods and beverages. In some cases they've been largely forgotten, like small beer. In other cases, it's been forgotten they're fermented, like cheese.
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the preferred method for making stored foods and drink bacteriologically safe was fermentation with a benign organism
Yeah. [youtube.com]
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Not always true. Sometimes it smells like a sweaty sock.
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Save water... (Score:2, Troll)
Sounds fine, but ... (Score:3, Funny)
Step in the right direction. (Score:5, Insightful)
Most of the time we see tasks like this as a mechanical engineering or a chemistry problem. However, there are severe limits on our the materials we use and how they are formed. Using biology (natural or engineered) to solve these types of small problems is a step toward a superior solution. I certainly hope our advances in genetic editing will be used to augment more biology into our engineered systems so that we can take advantage of nature's amazing ability to construction small and sophisticated structures which we could only dream of building otherwise.
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That sort of problem is always a risk though. You can't just overload water filtration systems with poison or other bio-hostile substances which is why stuff grows on your water bottle. Many of these cultures aren't particularly dangerous but if you can replace the random growth with something we intentionally place there and have studied its risk factors, that's probably safer.
I haven't heard of any situations where intentionally introducing "good" bacteria has caused an increase in resilience of the "ba
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Because biology... umm... finds a way.
No, because of "nature's amazing ability to construction small and sophisticated structures which we could only dream of building otherwise" which I mentioned.
Into places where it should never be, which are hard to clean, expensive to replace or hazardous to have clogged up.
If you designed it poorly then you will have this problem. If you designed it with this in mind it's less of an issue.
Not to mention all that lovely potential for breeding one of those "97 percent of the bacteria present", or the other 3 percent, into something like a new, antibiotic resistant breed of a pest which then finds our lungs or kidneys a great place to live.
You seem to be focused on this particular application but like I said, it's a step in the right direction. The ideal outcome would be a fully bioengineered structure that took unfiltered water in, had a tube that released filtered wa
Cost? (Score:2)
Refreshing? (Score:2)