Biocatalysis

For another take on the impact of Craig Venter’s accomplishment in creating a designed organism

Frances Arnold’s group at the California Institute of Technology (Caltech) and gene-synthesis company DNA2.0 have reported the construction of 15 new highly stable fungal enzyme catalysts that efficiently break down cellulose into sugars at high temperatures. Previously, fewer than 10 such fungal cellobiohydrolase II enzymes were known. In addition to their remarkable stabilities, Arnold’s enzymes degrade cellulose over a wide range of conditions.

Thermostability is a requirement of efficient cellulases, because at higher temperatures–say, 70 or even 80 degrees Celsius–chemical reactions are more rapid. In addition, cellulose swells at higher temperatures, which makes it easier to break down. Unfortunately, the known cellulases from nature typically won’t function at temperatures higher than about 50 degrees Celsius.

“Enzymes that are highly thermostable also tend to last for a long time, even at lower temperatures,” Arnold says. “And, longer-lasting enzymes break down more cellulose, leading to lower cost.”

“This is a really nice demonstration of the power of synthetic biology,” Arnold says. “You can rapidly generate novel, interesting biological materials in the laboratory, and you don’t have to rely on what you find in nature. We just emailed DNA2.0 sequences based on what we pulled out of a database and our recombination design, and they synthesized the DNA. We never had to go to any organism to get them. We never touched a fungus.”

See the full press release here.