Lots of People like beer and now they can pretend that the only reason that they are drinking beer is to help in recycling metals from e-waste. Basically in a new study published in Frontiers in Bioengineering and Biotechnology, researchers found that residual yeast sludge generated after beer is brewed is very good at isolating and taking up specific metals from a solution of mixed metals.
This would mean that it can be used to extract metals from e-waste, which is currently a very inefficient process that requires a lot of energy and manual effort, plus it generates a lot of toxic gases which kind of negates the whole point of recycling.
The researchers rinsed, froze, dried and ground up 20 liters of residue with inactive yeast from a brewery. Next they added some of the yeast to solutions containing a laboratory-made mix of aluminum, copper, nickel and zinc, then added some to solutions with those same metals leached directly from scrapped printed circuit boards. The researchers adjusted the mixtures’ acidity and temperature to alter the charge of sugar molecules on the yeast organisms’ surfaces; particular metals are drawn to specific charges on the sugars, so this process controlled which metals the yeast attracted and bound. After each attempt, the scientists extracted the yeast and soaked it in an acid bath to remove the metals from it, leaving the yeast ready for another round.
The four tested metals are relatively inexpensive, and most e-waste recyclers currently prioritize recovering more valuable ones such as gold, silver and platinum. But the study’s metals are still beneficial and widely used—which “justifies the recycling process,” says Treavor Boyer, an environmental engineer at Arizona State University. Kerry Bloom, a biologist at the University of North Carolina at Chapel Hill, adds that the yeast’s low price and sheer abundance could make the technique relatively feasible at a large scale
Setting up a recycling plant near a brewery would make this a cost efficient way to recycle metals. In fact in the traditional recycling methods we focus on metals like gold, silver and platinum because it is not cost effective to recycle metals like zinc, aluminum etc. So the new method can increase the amount of metal recycled at a lower cost. However, the paper doesn’t say if they tested it on the more expensive metals or not. I doubt they did, because if they had it would have been a great advantage to move to the new process.
Obviously, the process is still experiemental and needs a lot more refining and work before it can be used in an industrial scale. But it is a great step forward.
Source: Scientificamerican.com: After Brewing Beer, Yeast Can Help Recycle Metals from E-waste
– Suramya