Inactive yeast could be effective as an inexpensive, abundant, and simple material for removing lead contamination from drinking water supplies, according to a new analysis by scientists at MIT's Center for Bits and Atoms (CBA). The study shows that this approach can be efficient and economical, even down to part-per-billion levels of contamination. Serious damage to human health is known to occur even at these low levels.
The method is incredibly efficient. In fact, the research team has calculated that waste yeast discarded from a single brewery in Boston would enough to treat the city's entire water supply. Such a fully sustainable system would not only purify the water but also divert what would otherwise be a waste stream needing disposal.
[...] "We don't just need to minimize the existence of lead; we need to eliminate it in drinking water," says Stathatou. "And the fact is that the conventional treatment processes are not doing this effectively when the initial concentrations they have to remove are low, in the parts-per-billion scale and below. They either fail to completely remove these trace amounts, or in order to do so they consume a lot of energy and they produce toxic byproducts."
[...] Because the yeast cells used in the process are inactive and desiccated, they require no particular care, unlike other processes that rely on living biomass to perform such functions which require nutrients and sunlight to keep the materials active. What's more, yeast is abundantly available already, as a waste product from beer brewing and from various other fermentation-based industrial processes.
Stathatou has estimated that to clean a water supply for a city the size of Boston, which uses about 200 million gallons a day, would require about 20 tons of yeast per day, or about 7,000 tons per year. By comparison, one single brewery, the Boston Beer Company, generates 20,000 tons a year of surplus yeast that is no longer useful for fermentation.
[...] Devising a practical system for processing the water and retrieving the yeast, which could then be separated from the lead for reuse, is the next stage of the team's research, they say.
"To scale up the process and actually put it in place, you need to embed these cells in a kind of filter, and this is the work that's currently ongoing," Stathatou says. They are also looking at ways of recovering both the cells and the lead. "We need to conduct further experiments, but there is the option to get both back," she says.
The same material can potentially be used to remove other heavy metals, such as cadmium and copper, but that will require further research to quantify the effective rates for those processes, the researchers say.
Journal Reference:
Patritsia M. Stathatou, Christos E. Athanasiou, Marios Tsezos, et al. Lead removal at trace concentrations from water by inactive yeast cells [open], Communications Earth & Environment, 2022. DOI: 10.1038/s43247-022-00463-0
(Score: 1, Funny) by Anonymous Coward on Friday June 24 2022, @07:19PM (3 children)
Beer ... what can't it do?
(Score: 3, Funny) by DeathMonkey on Friday June 24 2022, @07:26PM (1 child)
Prevent a lifetime appointment to the Supreme Court!
(Score: 2) by Opportunist on Friday June 24 2022, @07:29PM
Well, indirectly... it can at least shorten that lifetime considerably if you drink enough of it.
(Score: 2) by istartedi on Friday June 24 2022, @08:27PM
I was expecting somebody to say it's the cause of and solution to all of life's problems [youtube.com].
Appended to the end of comments you post. Max: 120 chars.
(Score: 4, Insightful) by Snospar on Friday June 24 2022, @07:30PM (8 children)
Before we start down a road we'll all regret, can someone confirm we have surplus yeast that isn't needed for beer production? I've had enough of recent "global supply chain" issues forcing me to dip into my reserve; I don't want to be greeted by empty shelves in the shops with friendly "Helping the Planet" banners where my beer should be.
Huge thanks to all the Soylent volunteers without whom this community (and this post) would not be possible.
(Score: 2) by DeathMonkey on Friday June 24 2022, @07:38PM (4 children)
They are only using the "inactive" yeast leftover at the end of the brewing process.
I think in the industry they call it BSG for "brewers spent grain."
(Score: 2, Funny) by Anonymous Coward on Friday June 24 2022, @08:17PM (1 child)
Here it's called Vegemite.
(Score: 0) by Anonymous Coward on Saturday June 25 2022, @03:31AM
So you guys always knew this stuff is good at cleaning you out.
(Score: 2) by NateMich on Friday June 24 2022, @11:18PM
That would actually be the grain, not the yeast. The grain is used before yeast is added.
(Score: 0) by Anonymous Coward on Saturday June 25 2022, @12:11AM
Milorganite!
(Score: 2, Funny) by Anonymous Coward on Friday June 24 2022, @08:08PM
Invert that. By drinking beer, you are causing breweries to have surplus yeast, thus saving the planet. So drink more beer.
(Score: 0) by Anonymous Coward on Friday June 24 2022, @10:31PM (1 child)
As a homebrewer, I can say for certain that this is a waste product. Spent yeast is dead yeast. You can't use it to brew. There is a process, somewhat common at least among homebrewers (not sure how frequently it's used in commercial brewing), of rinsing yeast from a primary fermenter. Basically, after you rack the beer off the yeast in the primary fermenter and transfer it to a secondary, you're left with a yeast cake at the bottom of the primary fermenter, composed of a mixture of yeast and proteins and such that precipitated out during fermentation. This can be recovered, rinsed to remove non-yeast solids and such, and used for another batch. But this process can only go on for so long. Personally, I've never used the same yeast more than twice. I don't know anyone who uses their yeast more than 3 times. It's diminishing returns.
So, the yeast that breweries throw out is dead, or at least at the end of its useful life cycle in brewing. There are a number of uses for it. It can be added to animal feed as a supplement. It can be used to make vegemite, if that's your thing. But most of it gets thrown out. So, this is a great way to make use of what would otherwise just be waste.
(Score: 0) by Anonymous Coward on Saturday June 25 2022, @03:36AM
No, the only problem with reusing yeast in brewing is if it starts to evolve and change and give you a different flavor profile than before. You make it sound like there is a fixed amount of yeast and some of it dies, and as you reuse it you are slowly getting less and less. It doesn't work that way. Each time you brew, you make a shit ton of yeast because it is growing and multiplying, so when you rinse it you save the viable yeast. Some home brewers will go on and on with a strain. The commercial outfits that manage their own yeast will let it go a dozen times or so and then use some that they've banked. They do that for consistency. Places like brewpubs and small breweries will purchase their yeast from a yeast company and let them do the yeast management.
(Score: 0) by Anonymous Coward on Friday June 24 2022, @08:11PM
I would like to know more *BURP*
(Score: 0) by Anonymous Coward on Friday June 24 2022, @09:47PM (1 child)
But this will impact on the global supply of Vegemite!
(Score: 3, Insightful) by janrinok on Saturday June 25 2022, @08:46AM
Fortunately I have a supply of Marmite instead.
(Score: 1) by khallow on Monday June 27 2022, @04:20AM
Well actually, no, it's not so known. This is just another pseudo-scientific "no safe level" claim.