Dr. Duchesne responds to media frenzy on fish sperm for rare earths
Note from the Publisher: Dr. Luc Duchesne was asked to respond to the wide ranging coverage this month from Newsweek to the Smithsonian Magazine that claim fish sperm may hold the secret to both the recycling and extraction of rare earths.
Fish sperm to extract rare earth elements: first come first serve for flowsheet integration
In December 2004 a group of Japanese scientists demonstrated that salmon sperm DNA can be used to purify some rare earth elements more particularly for heavy the heavy rare earths Thulium, Ytterbium, and Lutetium.
The discovery begat a pregnant hiatus across the wire, which spawned a fry of news articles that produced tongue-in-cheek rewrites.
At InvestorIntel we like to think of ourselves as those exceptional salmon specimens that jump over waterfalls to deliver unusual news perspectives…so, here we come.
The data is swimmingly credible and as necessary and complicated, as the results of some paternity tests in the Osarks: the phosphate residues in fish DNA sticks to rare earth elements under the right chemical conditions. Does it have to be salmon sperm DNA? No. Does it have to be DNA? No. But the authors were motivated by the possibility to recycle fish sperm as there are more than 10,000 tons/year of sperm from salmon, trout, and others that have been historically discarded as industrial wastes from fishery industries in Hokkaido, Japan. This gigantic wet spot offers a commercial opportunity to kill two birds with the same set of rocks.
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The business end of this research has everything to do with the phosphate residues of the DNA chains. Bacterial cell membranes have the same phosphate residues and the authors used bacterial walls to purify rare earths in previous studies.
According to results of the study, the adsorption capacity of salmon sperm DNA at recovering rare earths from solutions is equivalent to that of commercial cation exchange resins. But we also know from their materials and methods section that they were not able to pack the DNA into columns, rather they bound the DNA cellulose fibres, which they used in a bath process. This is a drawback of the technology as compared to cation exchange resins, which can be packed in columns through which pregnant solutions with rare earths are eluted.
But absorption onto the sperm can specifically isolate Ytterbium, and Lutetium because of the larger differences in their affinities to sperm compared with other rare earths. So, in the development of flow sheets at the later stage of rare earths separation we have the choice to use resins or DNA batch processes. At this point in time the data points to resins as being the method with the best commercial outlook. However, we need side-by-side comparisons to understand if the use of salmon DNA offers an advantage over the resins or even over solvent extraction processes.
We might be a long way to have a salmon swimmer as a Marvel character with dysprosium magnet power or an action figure with a remote-controlled wiggly tail. But this warrants pre-commercial investigation as it may provide opportunities for integration into pre-existing flow sheets, specially in those cases where separation costs are costly.
As of now there are no patent filings on WIPO about this technology. Therefore the opportunity is waiting for anyone to claim paternity on its application. This is a case of first come-first serve.
Dr. Luc C. Duchesne is a Speaker and Author with a PhD in Biochemistry. With three decades of scientific and business experience, he has published ... <Read more about Dr. Luc Duchesne>