In the Microbial Sciences Building at the University of Wisconsin-Madison, the incredibly efficient eating habits of a fungus-cultivating termite are surprising even to those well acquainted with the insect’s natural gift for turning wood to dust.
According to a study published today (April 17, 2017) in the journal Proceedings of the National Academy of Sciences, when poplar wood undergoes a short, 3.5-hour transit through the gut of the termite, the emerging feces is almost devoid of lignin, the hard and abundant polymer that gives plant cells walls their sturdiness. As lignin is notorious for being difficult to degrade, and remains a costly obstacle for wood processing industries such as biofuels and paper, the termite is the keeper of a highly sought after secret: a natural system for fully breaking down biomass.
“The speed and efficiency with which the termite is breaking down the lignin polymer is totally unexpected,” says John Ralph, a UW-Madison professor of biochemistry, researcher at the Great Lakes Bioenergy Research Center (GLBRC) and lignin expert. “The tantalizing implication is that this gut system holds keys to breaking down lignin using processes that are completely unknown.”
To make biofuels, tiny microbes can be used to break down plant cells. As part of that digestive process, specialized enzymes break down cellulose—a major molecule that makes plant cell walls rigid. Scientists showed that an enzyme, from the bacterial glycoside hydrolase family 12, plays an unexpectedly important role in breaking down a hard-to-degrade crystalline form of cellulose. Surprisingly, the enzyme breaks apart the cellulose via a random mechanism unlike other hydrolases.
Breaking down cellulose is a major challenge in developing more efficient strategies for converting plant biomass to fuels and chemicals. The discovery of a specialized enzyme that is highly effective at breaking down rigid plant cell wall components could be harnessed to solve this challenge.
By Gillian Flaccus and Phuong Lee / The Associated Press
RIDDLE — John Redfield watches with pride as his son moves a laser-guided precision saw the size of a semi-truck wheel into place over a massive panel of wood.
Redfield’s fingers are scarred from a lifetime of cutting wood and now, after decades of decline in the logging business, he has new hope that his son, too, can make a career shaping the timber felled in Southern Oregon’s forests.
That’s because Redfield and his son work at D.R. Johnson Lumber Co., one of two U.S. timber mills making a new wood product that’s the buzz of the construction industry. It’s called cross-laminated timber, or CLT, and it’s made like it sounds: rafts of 2-by-4 beams aligned in perpendicular layers, then glued — or laminated — together like a giant sandwich.
The resulting panels are lighter and less energy-intensive than concrete and steel and much faster to assemble on-site than regular timber, proponents say. Because the grain in each layer is at a right angle to the one below and above it, there’s a counter-tension built into the panels that supporters say makes them strong enough to build even the tallest skyscrapers.
“We believe that two to five years out, down the road, we could be seeing this grow from just 20 percent of our business to potentially 60 percent of our business,” said Redfield, D.R. Johnson’s chief operating officer. “We’re seeing some major growth factors.”
From Maine to Arkansas to the Pacific Northwest, the material is sparking interest among architects, engineers and researchers. Many say it could infuse struggling forest communities like Riddle with new economic growth while reducing the carbon footprint of urban construction with a renewable building material.
By CATHERINE KAVANAUGH
A 2-year-old Maine start-up called Revolution Research Inc. was awarded a $100,000 federal grant to support its development of eco-friendly ceiling tiles made of a cellulose-based polymer.
Nadir Yildirim, president of the Orono-based business, said his small staff is using forest-based raw materials and nanotechnology to create a product that is durable, has high insulation properties, and can be composted. His goal is to achieve a 90 to 95 percent recycle rate for an industry seeking sustainable management of construction and demolition (C&D) materials.
ACS Sustainable Chem. Eng., 2016, 4 (12), pp 6355–6361
The use of renewable biomass for production of heat and electricity plays an important role in the circular economy. Degradation of wood biomass to produce heat is a clean and novel process proposed as an alternative to wood burning, and could be used for various heating applications. So far, wood degradation has mostly been studied at ambient temperatures. However, the process needs to occur at elevated temperatures (40–55 °C) to produce useable heat. Our objective was to study wood degradation at elevated temperatures for its potential application on heat production. Two (a thermotolerant and a thermophilic) fungi with different degradation strategies were chosen: lignin-degrading Phanerochaete chrysosporium and cellulose-degrading Chaetomium thermophilum. Each fungus was inoculated on nonsterile and sterile birch woodblocks to, respectively, study their wood degradation activity with and without natural biota (i.e., microorganisms naturally present in wood). The highest wood decay rates were found with C. thermophilum in the presence of natural biota, followed by P. chrysosporium under sterile conditions. The estimated theoretical value of heat production with C. thermophilum under nonsterile conditions was 0.6 W kg–1 wood. In conclusion, C. thermophilum seems to be a promising fungus to degrade wood together with natural biota, as sterilization of wood is not feasible in practice. Further testing on a larger scale is needed to implement the obtained results and validate the potential of biological wood degradation for heat production.
Posted by Stanford
A new process makes hydrogels out of cheaper materials. Tests show they can be useful for more applications, including wine-making and firefighting.
Hydrogels are gelatinous amalgams of cross-linked polymers that can absorb and hold large quantities of water. They’re useful in absorbent disposable diapers, as well as soft contact lenses.
Were it not for factors including high manufacturing costs, hydrogels could find even broader commercial application. The synthetic polymers now used for their production are often expensive or difficult to make on an industrial scale, and frequently present environmental and safety concerns. But those limitations may soon vanish.
A team of researchers has created new hydrogels that incorporate two abundant and inexpensive basic ingredients: a cellulose polymer derived from natural sources such as wood chips and agricultural waste; and colloidal silica, a liquid suspension of nanoscale particles derived from sand.
RIVERSIDE, Calif. (www.ucr.edu) — Lignocellulosic biomass—plant matter such as corn residues, grasses, straws, and wood chips—is an abundant and sustainable waste product ideal for the production of renewable fuels and chemicals. But breaking down biomass, through a process known as pretreatment, is one of the most expensive and energy-intensive steps in its conversion to renewable products.
In research published recently in the Journal of the American Chemical Society, a team from the U.S. Department of Energy’s (DOE’s) Oak Ridge National Laboratory (ORNL) and the University of California, Riverside (UCR) has now discovered new mechanisms that assist in biomass breakdown during aqueous pretreatment.
Abundant, chock full of energy and bound so tightly that the only way to release its energy is through combustion — lignin has frustrated scientists for years. With the help of an unusual soil bacteria, researchers at Sandia National Laboratories believe they now know how to crack open lignin, a breakthrough that could transform the economics of biofuel production.