Biology: 2001

Understanding culture, technology, and politics in "The Biological Century"

Gregory Benford from the November 1995 issue

(Page 3 of 7)

The theme in the Biological Century will be biological balancewhat's waste to one creature can become food to anotherwith a desirable job done in the transaction. This is "homeostasis," the biological equivalent of the thermostat. Such ecology on a small scale could become a public sign of trendy virtue, as popular as recycling is today.

Biotech revisits ancient arts. For many millennia we've been breeding cows and corn, collard greens and collies, to our whim. We can expect more exotic foods, of course, but as important, we may see new and better ways of growing them.

Ants and Analogies

Consider a field of maizecorn, to Americans. At its edge a black swarm marches in orderly, incessant columns. In one column, each ant carries a kernel of corn. In another, each carries bits of husk. In still another, an entire team coagulates around a chunk of a cob. The streams split, kernel-carriers trooping off to a ceramic tower, climbing a ramp and letting their burdens rattle down into a sunken vault. Each returns dutifully to the field. Another, thicker stream spreads into rivulets which leave their burdens of scrap at a series of neatly spaced anthills; dun-colored domes with regularly spaced portals, for more workers.

These had once been leaf-cutter ants, content to slice up fodder for their own tribe. They still do, pulping the unneeded cobs and stalks and husks, growing fungus on the pulp deep in their warrens. They were already tiny farmers in their own right. But biotech had genetically engineered them to harvest and sort first, processing corn right down to the kernels.

Other talents can be added. Acacia ants already defend their mother trees, weeding out nearby rival plants, attacking other insects which might feast on the acacias. Take that ability and splice it into the corn-harvesters, and you do not need pesticides, or the drudge human labor of clearing the groves. Can the acacia ants be wedded to corn? We don't know, but it does not seem an immense leap. Ants are closely related and multi-talented. Evolution seems to have given them a wide, adaptable range.

Following chemical cues, they seem the antithesis of clanky robots, though insects are actually tiny automatons engineered by evolution, the engine that favors fitness. Why not just co-opt their ingrained programming, then, at the genetic level, and harvest the mechanics from a compliant Nature? After all, agriculture is the oldest biotech. But everything else will alter, too.

Mining is the last great, traditional industry to be touched by the modern. We still dig up crude ores, extract minerals with great heat or toxic chemicals, and bring to the surface unwanted companion chemicals. All that suggests mining must be rethoughtbut on what scale? "Biomining" is actually quite ancient.

Romans working the Rio Tinto mine in Spain 2,000 years ago noticed fluid runoff of the mine tailings was blue, suggesting dissolved copper salts. Evaporating this in pools gave them copper sheets. The real work was done by a bacterium, Thiobacillus ferroxidans. It oxidizes copper sulfide, yielding acid and ferric ions, which in turn wash copper out of low-grade ores. This process was rediscovered and understood in detail only in this century, with the first patent in 1958.

A new smelter can cost a billion dollars. Dumping low-quality ore into a sulfuric-acid pond lets the microbes chew up the ore, with copper caught downhill in a basin; the sulfuric acid gets recycled, at trivial cost. Already a quarter of all copper in the world, from Peru to Alaska, comes from such bio-processing.

Gold enjoys a similar biological heritage. The latest scheme simply scatters bacteria cultures and fertilizers over open ore heaps, then picks grains out of the runoff. This raises gold recovery rates from 70 percent to 95 percent. There is not much room for improvement. Phosphates for agriculture can be had with a similar, two-bacteria method. By noticing that our mining waste was food for another phylum, we close a biological loop, cleanse our human world of "pollution," extend our resources, and make a profit.

All these developments use "natural biotech." Farming began by using wild wheata grass. Antibiotic therapy first started with unselected strains of Penicillium. We've learned much, mostly by trial and error, since then. The next generation of biomining bacteria are already emerging. A major problem with the natural strains is the heat they produce as they oxidize ore, which can get so high that it kills the bacteria.

To fix that, researchers did not go back to scratch in the lab. Instead, they searched deep-sea volcanic vents and hot springs, such as those in Yellowstone National Park. They reasoned that only truly tough bacteria could survive there, and indeed, found some which appear to do the mining job and can take near-boiling temperatures.

Bacteria also die from heavy-metal poisoning, just like us. To make biomining bugs impervious to mercury, arsenic, and cadmium requires bioengineering, currently under way. One tries varieties of bugs with differing tolerances, then breeds the best to amplify the trait. This can only take you so far. After that, it may be necessary to splice DNA from one variety into that of another, forcibly wedding across species.

We are already in the Easy Era. Around us, often without fanfare, emerge new technologies: engineered drugs, pest-resistant plants, single-gene alterations in plants and animals, genetic diagnostics (though usually only DNA testing of suspects makes the news). Within two decades we shall see "bioactive" products which work and live among us and in us, engineered organisms, "pharms," and limited genetic editing.