No Eureka Moments in Long U.S. Campaign to Crack Cellulosic Code
by Paul Voosen (New York Times/Greenwire) …For eons, plants have locked the sun’s energy into complex strands of sugar, used to build their stems and leaves. These chains are far different from table sugar or grain starch; they cling together, providing the meat of tree trunks and cotton strands. They are the most abundant organic material on the planet, and one of the most hunted.
As long as plants have built up these complex sugars, life in all its forms, from microbes to mastodons, has sought ways to unleash that energy. Since plants can’t run, and live for hundreds of years, they have built remarkable defenses, wrapping their cellulose, as the sugars are called, in a sort of barbed wire that, to this day, defies human degradation.
…At their most hopeful, scientists envision fields of ultra-productive grasses and trees growing on degraded land, the plants providing the energy for a new American century.
…Neither technology has landed a hard blow on the other, said Philippe Lavielle, the chief of business development at Genencor, the Dupont division focused on microbial engineering. Dupont doesn’t need the government’s guarantees, though it does need its fuel mandates and subsidies; if its first refinery fails, the company won’t abandon its plans, he said.
“I think the two [technologies] will play for a while,” Lavielle said. “The two will find their niche over time. My guess is there will be five to six technologies that will eventually find their space.”
…”We solved the problem of using all the sugars during fermentation,” Somerville said on a recent tour of Calvin Hall. “We’ve figured out how to engineer strains to simultaneously [use] all the sugars with very high rates. It’s good enough that the company moved it into commercialization already.”
…JGI’s rumen study, published early this year in Science, generated some 28,000 genes that appeared to encode similar proteins. And these were full genes, not the fragments like the termite study, Rubin said.
It was a stunning diversity of proteins. “The past 40 years, people have been looking for these enzymes, and in this one study we double the numbers,” he said.
The rumen team was interested in more than hypothesizing these proteins existed. They pulled 90 proteins from the rumen and tested them individually against grasses and model carbohydrates; 51 showed at least some activity against one of the feedstocks, suggesting at least half the team’s flagged enzymes were real.
Perhaps most impressively from the point of pure science, the team was able to divine nearly complete genomes for several microbial species, out of an estimated 1,000 bugs expected in the rumen.
…”The rotting log in a forest is not an industrial environment,” he said. “A termite’s gut is not an industrial environment. Natural evolution does not get you what industrialized mankind needs.”
…JGI is not resting on its rumen laurels. It has dozens of sequencing projects under way, many at the behest of JBEI or EBI. They’re looking at kangaroo and wallaby guts, and dung beetles, too. Then there’s the shipworm mollusk, which carries wood-fond microbes; it is said shipworms marooned Columbus in the West Indies for a year.
…”There’s going to be a bunch of incremental advances that will slowly make the cost calculations better,” he said. READ MORE