Scientists persuade nature to make silicon-carbon bonds
A new study is the first to show that living organisms can be persuaded to make silicon-carbon bonds—something only chemists had done before. Scientists at Caltech “bred” a bacterial protein to have the ability to make the man-made bonds, a finding that has applications in several industries.
Molecules with silicon-carbon, or organosilicon, compounds are found in pharmaceuticals as well as in many other products, including agricultural chemicals, paints, semiconductors, and computer and TV screens. Currently, these products are made synthetically, since the silicon-carbon bonds are not found in nature.
The new research, which recently won Caltech’s Dow Sustainability Innovation Student Challenge Award (SISCA) grand prize, demonstrates that biology can instead be used to manufacture these bonds in ways that are more environmentally friendly and potentially much less expensive.
“We decided to get nature to do what only chemists could do—only better,” says Frances Arnold, Caltech’s Dick and Barbara Dickinson Professor of Chemical Engineering, Bioengineering and Biochemistry, and principal investigator of the new research, published in the Nov. 24 issue of the journal Science.
The study is also the first to show that nature can adapt to incorporate silicon into carbon-based molecules, the building blocks of life. Scientists have long wondered if life on Earth could have evolved to be based on silicon instead of carbon. Science-fiction authors likewise have imagined alien worlds with silicon-based life, like the lumpy Horta creatures portrayed in an episode of the 1960s TV series Star Trek. Carbon and silicon are chemically very similar. They both can form bonds to four atoms simultaneously, making them well suited to form the long chains of molecules found in life, such as proteins and DNA.
“No living organism is known to put silicon-carbon bonds together, even though silicon is so abundant, all around us, in rocks and all over the beach,” says Jennifer Kan, a postdoctoral scholar in Arnold’s lab and lead author of the new study. Silicon is the second most abundant element in Earth’s crust.
The researchers used a method called directed evolution, pioneered by Arnold in the early 1990s, in which new and better enzymes are created in labs by artificial selection, similar to the way that breeders modify corn, cows, or cats. Enzymes are a class of proteins that catalyze, or facilitate, chemical reactions. The directed evolution process begins with an enzyme that scientists want to enhance. The DNA coding for the enzyme is mutated in more-or-less random ways, and the resulting enzymes are tested for a desired trait. The top-performing enzyme is then mutated again, and the process is repeated until an enzyme that performs much better than the original is created.
Directed evolution has been used for years to make enzymes for household products, like detergents; and for “green” sustainable routes to making pharmaceuticals, agricultural chemicals, and fuels.
In the new study, the goal was not just to improve an enzyme’s biological function but to actually persuade it to do something that it had not done before. The researchers’ first step was to find a suitable candidate, an enzyme showing potential for making the silicon-carbon bonds.
“It’s like breeding a racehorse,” says Arnold, who is also the director of the Donna and Benjamin M. Rosen Bioengineering Center at Caltech. “A good breeder recognizes the inherent ability of a horse to become a racer and has to bring that out in successive generations. We just do it with proteins.”
The ideal candidate turned out to be a protein from a bacterium that grows in hot springs in Iceland. That protein, called cytochrome c, normally shuttles electrons to other proteins, but the researchers found that it also happens to act like an enzyme to create silicon-carbon bonds at low levels. The scientists then mutated the DNA coding for that protein within a region that specifies an iron-containing portion of the protein thought to be responsible for its silicon-carbon bond-forming activity. Next, they tested these mutant enzymes for their ability to make organosilicon compounds better than the original.
After only three rounds, they had created an enzyme that can selectively make silicon-carbon bonds 15 times more efficiently than the best catalyst invented by chemists. Furthermore, the enzyme is highly selective, which means that it makes fewer unwanted byproducts that have to be chemically separated out.
“This iron-based, genetically encoded catalyst is nontoxic, cheaper, and easier to modify compared to other catalysts used in chemical synthesis,” says Kan. “The new reaction can also be done at room temperature and in water.”
The synthetic process for making silicon-carbon bonds often uses precious metals and toxic solvents, and requires extra processing to remove unwanted byproducts, all of which add to the cost of making these compounds.
As to the question of whether life can evolve to use silicon on its own, Arnold says that is up to nature. “This study shows how quickly nature can adapt to new challenges,” she says. “The DNA-encoded catalytic machinery of the cell can rapidly learn to promote new chemical reactions when we provide new reagents and the appropriate incentive in the form of artificial selection. Nature could have done this herself if she cared to.”
Learn more: Bringing Silicon to Life
The Latest on: Silicon-carbon bonds
via Google News
The Latest on: Silicon-carbon bonds
- Silicon Motion (SIMO) Q2 Earnings Beat Estimates, Revenues Lagon July 28, 2022 at 11:49 pm
Silicon Motion Technology Corporation SIMO reported ... Ingevity’s primary strategy is to produce high-performance activated carbon materials and specialty chemicals.
- Silicon Motion (SIMO) Q2 Earnings Beat Estimates, Revenues Lagon July 28, 2022 at 11:25 am
Silicon Motion Technology Corporation SIMO reported mixed second ... Ingevity’s primary strategy is to produce high-performance activated carbon materials and specialty chemicals. Assurant, Inc. AIZ, ...
- Silicon Laboratories (SLAB) Beats Q2 Earnings and Revenue Estimateson July 27, 2022 at 1:11 pm
Silicon Laboratories (SLAB) came out with quarterly earnings of $1.17 per share, beating the Zacks Consensus Estimate of $0.91 per share. This compares to earnings of $1.05 per share a year ago. These ...
- Global Silicon Carbide Power Electronics Market Report 2022: Next Generation Automation of EVs and Home and Campus Electricity storageon July 25, 2022 at 3:18 am
Dublin, July 25, 2022 (GLOBE NEWSWIRE) -- The "Silicon Carbide Power Electronics: Market Shares, Market Forecasts, Market Analysis, 2022-2028" report from Wintergreen Research, Inc has been added ...
- The Global Silicon Nitride Market is expected to grow by $ 45.84 mn during 2022-2026, accelerating at a CAGR of 7.12% during the forecast periodon July 22, 2022 at 5:56 am
New York, July 22, 2022 (GLOBE NEWSWIRE) -- Reportlinker.com announces the release of the report "Global Silicon Nitride Market 2022-2026" - https://www.reportlinker ...
- Global Silicon Carbide Power Electronics Market to 2028: Market Growth is the Result of Rapid Adoption of EV Electric Vehicleson July 22, 2022 at 5:17 am
DUBLIN, July 22, 2022 /PRNewswire/ -- The "Silicon Carbide Power Electronics: Market Shares, Market Forecasts, Market Analysis, 2022-2028" report from Wintergreen Research, Inc has been added to ...
- Flexible Polymer Paves Way for Organic Semiconductorson July 21, 2022 at 5:00 pm
Researchers at the University of California, Santa Barbara (UCSB), have come up with an alternative to silicon in these devices with a new, soft, semiconducting carbon-based polymer ... with ...
- Nano Silicon Carbon Anode Material Market 2022 Size, Share, Growth Potential, Dynamics, Development Ideas, Top Manufacturers and Forecast till 2028on July 21, 2022 at 4:37 am
Is there a problem with this press release? Contact the source provider Comtex at [email protected] You can also contact MarketWatch Customer Service via our Customer Center. The MarketWatch ...
- Silicon Carbide Market Size: Regional Segment Analysis, forecast and market revenue 2022-2031on July 21, 2022 at 4:06 am
is a type of chemical compound made of silicon and carbon. Also, SiC has the huge potential to replace other silicon-based semiconductors and transistors due to their low switching cost and can ...
via Bing News