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Emily Greenstreet
Harlynn Ramsey
Writing 340
April 29, 2013
Nanocellulose
Abstract
In a world desperate for renewable material resources and reduced carbon emissions,
nanocellulose is increasingly being viewed as a wonder material. Lightweight, strong,
and plant-based, it can be incorporated in a huge variety of products, ranging from food
to automobiles. It shows particular promise in the medical field where its natural
composition allows it to be used to support bone, cartilage, and vascular re-growth, in
addition to being suitable for the construction of artificial body parts. New
manufacturing techniques have reduced costs and increased production to the point
where nanocellulose will replace metals and oil-based plastics in many products within
the next ten years.
Tags: nanocellulose, algae, renewable materials, biochemical engineering, biomedical
engineering, health & medicine
About the Author:
Emily Greenstreet is a fourth year Bachelor of Architecture Student. She is an active
member of the Undergraduate Architecture Student Council at USC as well as a
mathematics tutor for local high school students. She currently works for D.P.
Environment, a Los Angeles based landscape architecture firm.
Cellulose
Cellulose is the most abundant natural substance on earth. It is a material that has been
used by mankind since the dawn of civilization [1]. Wood; hay; papyrus; cotton; all are
natural manifestations of cellulose. It’s the fiber in oatmeal, and in modified form
provides the thickening agent for fast food milkshakes. Now, scientists working with a
cellulose derivative, nanocellulose, are calling it the next wonder material. Nanocellulose
is produced when cellulose is reduced down to nanosized (5-20nm diameter) cellulose
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fibrils. This material has great potential because it is abundant, renewable, and
biodegradable [1].
Properties of Nanocellulose
Nanocellulose is incredibly versatile, offering a wide range of properties. This material is
lightweight, but can simultaneously be stiffer than Kevlar, making it perfect for
innovative armor. It’s non-toxic, offering possibilities for implantation in food products
[2]. It has eight times the tensile strength of steel, yet also offers the possibility to replace
traditional paper as a more sustainable material due to its lightweight and flexibility. A
one-pound boat made of this substance would be able to carry up to 1000 pounds of
cargo, proving the buoyancy of the material to be quite incredible [2]. Unexpectedly this
strong material in its crystalline form is transparent, a gel made of microfibrils, as shown
in Figure 1.
Figure 1: Nanocellulose as a thick paste (http://www.extremetech.com)
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Nanocellulose with its low weight, high strength and potential transparency is of great
interest for many applications in a wide variety of areas.
Production methods
The extraordinary properties and potential benefits of nanocellulose are clear, so why has
the material not taken off yet? When it was first studied in the 1980s, nanocellulose was
not commercially viable due to the high cost in manufacturing and the large amount of
energy required to delaminate the fibers [3]. In the current production process, cellulose
is milled, and then hydrolyzed to remove amorphous regions [4]. The resulting
nanocrystalline cellulose (NCC) is then separated and concentrated before being
customized for various uses. Homogenizers are used to remove non-cellulose impurities
from the wood pulp. The mixture then undergoes a gentle beating which separates the
cellulose fibers, creating a thick paste [5]. This paste can be shaped and readily used. One
company has created fiber pre-treatment methods, by which energy consumption can be
reduced up to 98% [6]. In an alternative approach just being introduced, biogenetically
altered algae can naturally create the nanocellulose while simultaneously helping to
address our energy issues by producing biofuel.
Genetically modified algae
Scientists have genetically engineered blue-green algae with genes from Acetobacter
xylinum, a vinegar bacterium that naturally secretes nanocellulose in a culture medium
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[5]. Figure 2 shows algae being cultured in a science beaker.
Figure 2: Cyanobacteria cultured in specific media (http://commons.wikimedia.org)
R. Malcolm Brown, Jr., Ph.D. is the lead scientist on this project. Brown, along with his
colleagues, has sequenced the first nanocellulose-producing genes from A. xylinum. He
was also able to pinpoint the genes that are involved in polymerizing nanocellulose [5].
Despite this discovery, there have been a variety of drawbacks making this bacterium
unsuccessful at producing a successful yield needed to produce commercial amounts of
nanocellulose. Instead, Brown and his team turned to blue-green algae, which when
engineered with the A. xylinum genes are able to produce a long-chain or polymer form of
the nanocellulose material [5]. This incredibly sustainable approach is based upon
fermentation tanks that require only water, sunlight, and algae. This new approach offers
the potential to create organic factories capable of making nanocellulose on an industrial
scale.
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Genetically altered cyanobacteria are entirely self-sustaining. Like any other plant, they
consume carbon dioxide as they grow, producing their own food from sunlight while
absorbing carbon dioxide emissions from the atmosphere. In fact, these algae have been
shown to thrive on smokestack emissions [7], and for highest productivity actually
require access to significantly increased concentrations of CO2 [8]. The required CO2
can be supplied through the establishment of binary facilities, where the algae growth
utilizes combustion gasses bubbled into their growth tanks from the smokestacks of a
factory or power plant, instantly sequestering the associated greenhouse gas.
A further benefit of using genetically modified algae to produce nanocellulose is that a
major byproduct is biofuel oil [5]. In the past, production of nanocellulose consumed
large amounts of energy. Now, because one of the major byproducts of nanocellulose
production through algae is biofuel, the results are a net increase in available energy.
Projected biodiesel production rates, given by Pike Research in a report for AEEI, are
claimed to be as high as 6500 gallons of fuel per acre per year, in comparison to ethanol
plants, which produce only 450 gallons per acre per year. Clearly this is an advancement
in production and should allow nanocellulose use to rapidly advance beyond current
applications in the food, biomedical, and cosmetics industries into more high-tech
composite materials.
Future of nanocellulose
Nanocellulose has only recently become a viable commercial material – this year (2013)
in fact following the refinement of the blue-green algae production process. However
there is already a huge range of potential applications of this material, and there are more
applications coming forward almost daily. It is a solution looking for more problems to
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solve. As a construction material it can be used in place of fiberglass to make 10% lighter
auto components, thus creating a proportional reduction in vehicle fuel consumption [10].
In the medical field the potential is enormous, both for the construction of new body
parts, and also as a scaffolding for the re-growth of cartilage, bone, and vascular
components. It can also be used for arthritis joint relief, and in making nanochitosan for
the instant clotting and sealing of traumatic wounds on the battlefield and in emergency
response [9]. And its potential is not constrained solely to the scientific field. It has
potential in the commerce. One of the most profitable applications may be in the food
industry, where the incorporation of nanocellulose into products offers the potential for a
wide range of new low-calorie alternatives such as fluffier, fiber-enhanced, ice cream.
The cosmetics industry will also benefit from new wrinkle-reducing products using
nanocellulose [9]. Even further into the future, NCC offers the potential for the creation
of a whole new class of transparent nanomaterials.
Wonder Material
It seems that every few years an eager group of engineers announces a new “wonder
material” which then fades into obscurity. This is unlikely to happen with nanocellulose.
With its flexibility, strength, and transparency, nanocellulose is poised to have longreaching effects upon many industries. With the introduction of genetically modified
algae, the production of nanocellulose can now not only address commercial needs, but
also help the current issue of greenhouse gas emission, providing benefits in carbon
sequestration and biofuel production that will ultimately help to reduce global warming.
With further publication and funding nanocellulose appears destined to gain widespread
support and enter large-scale production.
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References
[1] "Applications of Nanocellulose" StudyMode.com. 01 2012. 01 2012
<http://www.studymode.com/essays/Applications-Of-Nanocellulose899911.html>.
[2] Anthony, Sebastian. "Nanocellulose: A Cheap, Conductive, Stronger-than-Kevlar
Wonder Material Made from Wood Pulp." ExtremeTech. N.p., 23 Aug. 2012.
Web. 10 Apr. 2013.
[3] Turbak, A. F. Naylornetwork.com. Rep. N.p., n.d. Web. 10 Apr. 2013.
[4] Simončič, Barbara. Biodegradation of Cellulose Fibers. New York.: Nova Science,
2010. Print.
[5] American Chemical Society (ACS) (2013, April 7). Engineering algae to make the
'wonder material' nanocellulose for biofuels and more.
[6] "Nanocellulose." Innventia. N.p., n.d. Web. 10 Apr. 2013.
<http://www.innventia.com/en/Our-Expertise/New-materials/Nanocellulose/>.
[7] Toor, Amar. "Can We Grow a Stronger-than-steel 'wonder Material' to save the
World?" The Verge. Vox Media, 8 Apr. 2013. Web. 10 Apr. 2013.
[8] All About Algae. Rep. no. DE-EE0003118. Algae Biomass Organization, n.d. Web. 13
Apr. 2013.
[9] "Applications." CelluForce. N.p., n.d. Web. 10 Apr. 2013.
<http://celluforce.com/en/product_applications.php>.
[10] Turbak, A.F.; F.W. Snyder, and K.R. Sandberg (1983). "Microfibrillated Cellulose, a
New Cellulose Product: Properties, Uses, and Commercial Potential." In A. Sarko
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(ed.) Proceedings of the Ninth Cellulose Conference, Applied Polymer Symposia,
37, New York, N.Y., USA: Wiley. pp. 815–827. ISBN 0-471-88132-5.