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Transforming Nanocellulose

Regulatory uncertainties, lack of private investment hamper commercialization of products

by Britt E. Erickson
June 9, 2014 | A version of this story appeared in Volume 92, Issue 23

Transmission electron microscopy image of cellulose nanofibrils. TEM image of rough rod shapes.
Credit: U.S. Forest Service
Rod-shaped cellulose nanocrystals (left) and spaghetti-like cellulose nanofibrils, shown in these transmission electron microscope images, have the potential to be incorporated into numerous products.

Nanoscale cellulose particles are popping up in a dizzying number of applications. But despite their high commercial potential, investment in large-volume uses of the materials is low. Uncertainties related to the environmental, health, and safety aspects of the materials could also hinder commercialization of these products.

Cellulose nanomaterials have a lot going for them. These materials cost less to produce than other nanomaterials. They have a high strength-to-weight ratio and properties that make them promising for a wide variety of applications. Some of the most talked about products on the horizon include recyclable electronics, biobased plastics, paper and packaging materials with improved surfaces, flexible cement, lightweight parts for automobiles and aircraft wings, armor for soldiers, and additives for oil and natural gas drilling. Interest in cellulose nanomaterials is also growing because they are renewable—they can be isolated from trees, other plants, and algae, or they can be generated by bacteria.

Nanocellulose particles can be extracted from biomass in various ways, leading to particles with different behaviors. One of the most common ways is via acid hydrolysis with sulfuric or hydrochloric acid, which results in rice-shaped cellulose nanocrystals. Another method involves enzyme-mediated oxidation followed by mechanical ripping of cell-wall material, resulting in longer, spaghetti-like cellulose nanofibrils. Cellulose nanoparticles can also be decorated, like an ice cream cone with sprinkles, with functional groups, such as reactive hydroxyls, that alter the particles’ behavior.

As nanocellulose-based applications emerge from research laboratories and small start-up companies, federal officials are urging private investors to provide funds to turn innovations into commercial products. They cite the potential for economic growth and job creation, particularly in rural areas. Federal officials fear that if the private sector doesn’t act soon in the U.S., manufacturing of such products will end up overseas.

Cellulose nanomaterials are “exciting, game-changing materials that will play an important role in our future bioeconomy,” said Arthur (Butch) Blazer, deputy undersecretary for natural resources and environment at the Department of Agriculture. They open a path for novel uses of low-grade wood, such as trees killed by beetles or harvested during fire prevention operations. Cellulose nanomaterials also provide new ways of using wood fiber from traditional timber sources, he said.

Much of the infrastructure already exists for processing cellulose. Manufacturers of wood products, building materials, and pulp and paper are major contributors to local economies, especially in rural areas. Many of these plants are underutilized, Blazer said. Production of cellulose nanomaterials and products derived from them can boost production volume at such facilities.

Just one application—cellulose nanomaterials in the paper industry—could create 425,000 jobs in the U.S. by 2020, said Thomas Kalil, deputy director for technology and innovation at the White House Office of Science & Technology Policy.

Kalil and other federal officials are encouraging the private sector to invest in nanocellulose. The U.S. has 751 million acres of forests, 44% of which are managed by federal, state, and local governments, according to USDA’s Forest Service.

The U.S. government has invested about $20 million in nanocellulose research and development since 2009, compared with a combined $680 million by federal governments worldwide. The Forest Service first began investing in this area in 2005 as part of the National Nanotechnology Initiative (NNI)—a federal effort to coordinate nanotechnology R&D across U.S. government agencies. For fiscal 2015, the Obama Administration has requested that Congress provide $4 million for nanocellulose R&D.

U.S. taxpayer money has supported basic R&D projects, such as studies on the nanoscale structure of wood and characterization of nanocellulose materials. Federal dollars have also helped develop international standards for commercialization of nanocellulose products, said Cynthia West, associate deputy chief for R&D at the Forest Service.

The Forest Service made a critical $1.7 million investment in 2012 to fund a nanocellulose pilot plant at the Forest Products Laboratory in Madison, Wis., West said. The laboratory is the leading producer of nanocellulose materials in the U.S., with the capacity to generate 25-kg batches of cellulose nanocrystals and 2-kg batches of cellulose nanofibrils. The Forest Service also provided $1.5 million in 2011 to support the development and construction of a cellulose nanofibrils demonstration plant at the University of Maine.

The Forest Service late last year joined forces with the nonprofit U.S. Endowment for Forestry & Communities. They formed a three-year collaboration called the Public-Private Partnership for Advanced Woody Biomaterials & Nanotechnology, or PNano. It aims to overcome technical barriers to large-scale wood-based nanotechnology processing and to fill in the science and technology gaps related to commercialization of nanocellulose products.

Some of those barriers and research gaps were identified last month at a workshop in Washington, D.C., cosponsored by the Forest Service and NNI. In addition to the lack of industry partners to codevelop new products, participants pointed out that access to nanocellulose materials is limited. Additionally, such materials are expensive, and the environmental, health, and safety aspects of the materials have not been evaluated. Other unmet scientific challenges include a lack of information about dispersion and aggregation of cellulose nanoparticles and the need for cost-effective methods to dry such ­materials.

Regulatory challenges also exist. Workshop participants pointed to upcoming requirements in some European countries for labeling of consumer products that contain nanomaterials. France already has such a rule in place, said Bernard Cathala, a group leader of nanostructured assemblies and deputy director of the biopolymer unit at the National Agronomical Research Institute in France. It is unclear whether cellulose nanomaterials would fall under the European Union’s definition of a nanomaterial and whether they will be considered novel materials.

In the U.S., the Food & Drug Administration has declared nanosized cellulose produced by bacteria to be generally recognized as safe. It can be added to food as a thickening, binding, or gelling agent. Companies are evaluating the use of other nanocellulose materials, in particular cellulose nanofibrils, as a low-calorie food additive to replace fat in Chinese-style meatballs, to decrease the loss of hamburger’s weight when it is fried, and to provide a softer texture and better appearance to bread, Cathala said. It is unclear whether FDA will also consider these forms of nanocellulose to be generally recognized as safe.

Similarly, in the EU, microcrystalline cellulose is an approved food ingredient, but it is unclear whether cellulose nanocrystals and cellulose nanofibrils will be considered novel food ingredients that need to undergo rigorous safety evaluation.


Number of trees planted annually in U.S.: >1.5 billion

Size of U.S. forests: 751 million acres (44% managed by federal, state, and local governments)

Amount invested in nanocellulose R&D since 2009: $20 million (U.S. Forest Service), $680 million (global)

President’s request for fiscal 2015 Forest Service nanotechnology R&D: $4 million

Cellulose nanofibril capacity: ~7.5 tons/year (U.S.), ~50 million tons/year (global)

Cellulose nanocrystal capacity: ~1.3 tons/year (U.S.), ~30 million tons/year (global)

Wood demand: 187 million tons/ year (U.S.) Wood capacity: 405 million tons/ year (U.S.)

Year U.S. Forest Service began investing in nanotechnology: 2005 

Few studies have looked at effects of cellulosic nanomaterials on human health, said Charles L. Geraci Jr., coordinator of the Nanotechnology Research Center at the National Institute for Occupational Safety & Health. NIOSH studies the potential hazards of new materials on workers. The agency is currently evaluating whether cellulosic nanomaterials represent a workplace hazard, with a focus on exposure by inhalation, Geraci said.

Preliminary results suggest very low toxicity of cellulose nanomaterials in humans and the environment, said Jo Anne Shatkin, founder of Vireo Advisors, a firm that specializes in analyzing the risks of emerging materials.

As an example, Geraci said, “We see good clearance of nanocellulose out of the lung” in laboratory animals. NIOSH is following up with cellular toxicology tests looking for other indicators of toxicity—inflammation and oxidative stress, he added.

Despite the technical and regulatory challenges associated with nanomanufacturing and commercialization, the U.S. leads the world in commercial activity of nanotechnology. Several lawmakers and federal officials are concerned, however, because other countries are investing heavily in nanocellulose technology at a time when U.S. federal research dollars are dwindling.

The House of Representatives’ Science, Space & Technology Committee addressed the challenges facing the commercialization of nanotechnology products at a subcommittee hearing last month. “If we are going to remain competitive, then the U.S. needs to make strong and sustained investments in nanotechnology, enact federal policies that help technology and manufacturing development, and play a central role in international standards development,” the committee’s ranking member, Eddie Bernice Johnson (D-Texas), said. U.S. companies invested $4.1 billion in nanotechnology R&D in 2012, far more than companies in any other country, Lloyd Whitman, interim director of the National Nanotechnology Coordination Office, told the committee. The office coordinates NNI activities and serves as the central point of contact for federal nanotechnology R&D in the U.S.

Federal investment in nanotechnology R&D in the U.S. is relatively modest compared with private-sector spending. Yet taxpayer money supports “a critical pipeline of basic research, generating new innovations that will provide opportunities for future industry investments in applied R&D,” Whitman said. “It is essential that the U.S. continue to lead the way in innovation enabled by nanotechnology and other emerging technologies,” he said. “The nation’s economic growth and global competitiveness depend on it.”

Leading experts from academia, government, and the private sector are expected to gather in Vancouver, British Columbia, later this month to further map the path toward commercialization of nanocellulose-based products. The meeting, hosted by a pulp and paper industry trade organization, will showcase some of the latest applications from around the world.  


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