Mining Gold With Kary Mullis

I was reading Kary Mullis’ autobiography Dancing Naked in the Mind Field years ago and remember this passage:

I like to know about those things and all the diets and drugs we ingest to keep it all working. Furthermore, I like to fool around with it. I liked to make chemicals in the 1960s that had effects on my mind. I like to make chemicals in the 1990s that have serious effects on anything alive.

I like to make chemicals that could turn a sponge into a gold miner. A happy little creature that filtered water like a normal sponge might be endowed with a voracious appetite for filtering out the gold that washed down the Sacramento River out of them thar hills. I like to make chemicals that might help heal a spinal cord that had been crushed by its owner's motorcycle. I'd like to cure diabetes. This is what biochemists do.

Would the sponge miner work? Assume we could engineer a protein that chelates gold with high specificity and clone it into a sea sponge.

For harvesting >10k basketball-sized sponges after 10 years of waiting, this is a weak payout. Even with perfectly engineered chelation, the gold concentration in the ocean is just too low. Mullis’ idea of panning a river near known gold deposits might get the baseline concentration up, but then the gold is probably in irregular elemental nuggets that are more complicated to capture than ions.

It makes sense that Mullis would think of this after spending 6 years studying the iron chelator schizokinen for his Ph.D. Ernst Bayer achieved gold enrichment from seawater by chelation in the 1960s. Fritz Haber also tried to mine gold from seawater >100 years ago, but concluded that it was not economically viable.