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<div class=Section1>
<h1 style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:7.5pt;
margin-left:0in'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#222222;letter-spacing:-.4pt;font-weight:normal'><o:p> </o:p></span></h1>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Arial","sans-serif"'>Turning
cast-off shells into nitrogen-rich chemicals would benefit economies and the
environment, say Ning Yan and Xi Chen<span style='color:#222222;letter-spacing:
-.4pt'><o:p></o:p></span></span></p>
<p class=MsoNormal><b><span style='font-size:18.0pt;font-family:"Arial","sans-serif";
color:#222222;letter-spacing:-.4pt'>Sustainability: Don't waste seafood waste<o:p></o:p></span></b></p>
<p class=MsoNormal><span class=vcard><span style='font-size:12.0pt;font-family:
"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#auth-1"><span
style='color:#5C7996;border:none windowtext 1.0pt;padding:0in'>Ning Yan</span></a>
</span></span><span style='font-size:12.0pt;font-family:"Arial","sans-serif"'>&<span
class=apple-converted-space> </span><span class=vcard><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#auth-2"><span
style='color:#5C7996;border:none windowtext 1.0pt;padding:0in'>Xi Chen</span></a><o:p></o:p></span></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Arial","sans-serif";
color:#333333'>Department of Chemical and Biomolecular Engineering, National
University of Singapore, Singapore.<o:p></o:p></span></p>
<p class=MsoNormal><i>Nature </i><b>524, </b>155–157 (13 August 2015) doi:10.1038/524155a<o:p></o:p></p>
<h1 style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:7.5pt;
margin-left:0in'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#222222;letter-spacing:-.4pt;font-weight:normal'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0">http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0</a><o:p></o:p></span></h1>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Arial","sans-serif";
color:#333333'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:0in;text-indent:-.25in;mso-list:l4 level1 lfo1'><![if !supportLists]><span
style='font-size:10.0pt;font-family:Symbol'><span style='mso-list:Ignore'>·<span
style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><o:p> </o:p></p>
<p class=MsoNormal align=center style='text-align:center;line-height:17.85pt;
background:#ECECEC'><span style='font-size:10.0pt'><img border=0 width=630
height=416 id="Imagen_x0020_1" src="cid:image001.jpg@01D0D677.7EA577D0"
alt="http://www.nature.com/polopoly_fs/7.28633.1438942361!/image/sea1.jpg_gen/derivatives/landscape_630/sea1.jpg"></span><span
style='font-size:10.0pt'><o:p></o:p></span></p>
<p class=credit align=center style='margin:0in;margin-bottom:.0001pt;
text-align:center;background:#ECECEC'><i><span style='font-size:7.5pt;
color:#999999'>Jiang Kehong/Xinhua Press/Corbis<o:p></o:p></span></i></p>
<p class=caption align=center style='margin:0in;margin-bottom:.0001pt;
text-align:center;line-height:17.85pt;background:#ECECEC'><span
style='font-size:10.0pt'>Discarded shrimp shells contain nutrients that could
be used to enrich animal feed.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-size:8.0pt'><o:p> </o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Every year,
some 6 million to 8 million tonnes of waste crab, shrimp and lobster shells are
produced globally — about 1.5 million tonnes in southeast Asia alone</span><sup><span
style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b1"
title="Food and Agriculture Organization of the United Nations. The State of World Fisheries and Aquaculture (FAO, 2014)."
id=ref-link-1><span style='color:#5C7996'>1</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>. Whereas 75% of the weight of a tuna
fish can be extracted as fillets, meat accounts for only around 40% of a crab's
mass.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>In developing
countries, waste shells are often just dumped in landfill or the sea. In
developed countries, disposal can be costly — up to US$150 per tonne in
Australia, for example.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Yet shells
harbour useful chemicals —protein, calcium carbonate and chitin, a
polymer similar to cellulose, but which contains nitrogen (see 'Shell
biorefinery'). The potential value of such shells for the chemical industry is
being ignored. Scientists should work out sustainable ways to refine crustacean
shells, and governments and industry should invest in using this abundant and
cheap renewable resource.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Dried shrimp
shells are valued at a mere $100–120 per tonne. They can be ground down
and the powder used as an animal-feed supplement, bait or fertilizer, as well
as in chitin production. The return is not much more for agricultural residues
and wastes: corn stover and wheat straws, which are burned for heat or refined
into chemicals, sell for $50–90 per tonne.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Crustacean shells
are 20–40% protein, 20–50% calcium carbonate and 15–40%
chitin. What could these parts be used for?<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><b><span style='font-family:"Arial","sans-serif"'>Protein</span></b><span
class=apple-converted-space><span style='font-family:"Arial","sans-serif"'> </span></span><span
style='font-family:"Arial","sans-serif"'>is good for animal feeds. For example,<span
class=apple-converted-space> </span><i>Penaeus</i><span
class=apple-converted-space> </span>shrimp shells contain all the
essential amino acids and have a nutrient value comparable to that of soya-bean
meal. Today, the protein is not being used because the current processing
methods destroy it. As livestock breeding rises rapidly, waste crustacean
shells from southeast Asia could be transformed into protein-rich animal feed
with an annual market value of more than $100 million, according to World Bank
data.<o:p></o:p></span></p>
<p class=MsoNormal align=center style='text-align:center;line-height:17.85pt;
background:#ECECEC'><span style='border:none windowtext 1.0pt;padding:0in'><a
href="http://www.nature.com/news/524155a-i2-jpg-7.28634?article=1.18149"><span
style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#5E5E5E;
text-decoration:none'><img border=0 width=630 height=385 id="Imagen_x0020_2"
src="cid:image002.jpg@01D0D677.7EA577D0"
alt="http://www.nature.com/polopoly_fs/7.28634.1438942398!/image/Seafood2.jpg_gen/derivatives/landscape_630/Seafood2.jpg"></span></a></span><span
style='font-size:10.0pt;font-family:"Arial","sans-serif"'><o:p></o:p></span></p>
<p class=MsoNormal align=center style='text-align:center;line-height:17.85pt;
background:#ECECEC'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href="javascript:;" title=Expand><span style='color:#5E5E5E;border:none windowtext 1.0pt;
padding:0in'>Expand</span></a><o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><b><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></b></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><b><span style='font-family:"Arial","sans-serif"'>Calcium
carbonate</span></b><span class=apple-converted-space><span style='font-family:
"Arial","sans-serif"'> </span></span><span style='font-family:"Arial","sans-serif"'>has
extensive applications in the pharmaceutical, agricultural, construction and
paper industries. It currently comes mainly from geological sources such as
marble and limestone. These sources are plentiful but might contain heavy
metals that are difficult to remove. Chalk from shells would thus be better for
human consumption, for example as a constituent of pills. People might also
find it easier to accept tablets that originate from food sources than from
rocks.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>The market
price of ground calcium carbonate is around $60–66 per tonne for coarse
particles, which are used in construction, pigments, fillers and soil
treatments. Ultrafine particles, which can be used to improve the properties of
rubber and plastics, can reach an astonishing $14,000 per tonne. Even if the
calcium carbonate from southeast Asian crustacean shells was processed into
only the cheapest coarse particles, it could have an annual market value of up
to $45 million.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><b><span style='font-family:"Arial","sans-serif"'>Chitin</span></b><span
class=apple-converted-space><span style='font-family:"Arial","sans-serif"'> </span></span><span
style='font-family:"Arial","sans-serif"'>is a linear polymer and the second
most abundant natural biopolymer on Earth (after cellulose). It is found in
fungi, plankton and the exoskeletons of insects and crustaceans, and organisms
generate about 100 billion tonnes of chitin every year</span><sup><span
style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b2"
title="Kim, S. K. Chitin, Chitosan, Oligosaccharides and Their Derivatives: Biological Activities and Applications (CRD Press, 2011)."
id=ref-link-2><span style='color:#5C7996'>2</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>. Currently, the polymer and its water
soluble derivative, chitosan, are used in only a few niche areas of industrial
chemistry, such as cosmetics, textiles, water treatment and biomedicine. Its
potential is much greater.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Unlike most
other forms of biomass such as cellulose, chitin contains nitrogen.
Nitrogen-containing compounds — widely used in the pharmaceutical
industry, carbon dioxide fixation, textiles and beyond — are crucial for
modern life. For example, the nitrogen-containing organic compound pyrazine is
integral to several best-selling drugs such as eszopiclone (for sleeping
difficulties) and varenicline (to treat nicotine addiction). Ethanolamine (ETA)
is used in power plants for CO</span><sub><span style='font-size:9.0pt;
font-family:"Arial","sans-serif"'>2</span></sub><span style='font-family:"Arial","sans-serif"'>sequestration
and in skin-friendly soaps, household cleansers and surfactants. Nitrogen-containing
chemicals have a huge market — about 2 million tonnes of ETA are used a
year globally</span><sup><span style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b3"
title="Grand View Research. Amines Market Analysis By Product (Ethanolamines, Alkylamines, Fatty Amines), By Application (Crop Protection, Surfactants, Water Treatment, Personal Care) And Segment Forecasts To 2020 (Grand View Research, 2014); available at http:/"
id=ref-link-3><span style='color:#5C7996'>3</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>, with annual sales of around $3.5
billion.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>The industrial
production of nitrogen compounds involves fossil fuels and energy-intensive
processes. First, nitrogen gas must be converted into ammonia through the Haber
process, which is notorious for its low reaction efficiency. This process alone
accounts for an estimated 2–3% of global energy consumption. For every
mole of nitrogen gas consumed, three moles of hydrogen gas, derived from fossil
fuels, are used.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Further
processing is complex and expensive. For instance, generating ETA requires six
steps: hydrogen production from coal or natural gas; nitrogen isolation from
air; ammonia synthesis; ethylene production from crude-oil cracking; conversion
of ethylene into ethylene oxide; and then conversion of ethylene oxide into
ETA.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Chitin might be
a more suitable starting point for ETA production. With carbon, nitrogen and
oxygen already bound in the polymer, only one step is needed to make ETA.
Another five chemicals have been derived from chitin in a single step and the
list is growing. So far, however, this has been achieved on only a small scale
in the lab</span><sup><span style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b4"
title="Chen, X. & Yan, N. Catal. Surv. Asia 18, 164–176 (2014)."
id=ref-link-4><span style='color:#5C7996'>4</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>.<o:p></o:p></span></p>
<h2 style='margin:0in;margin-bottom:.0001pt'><span style='font-size:11.0pt;
font-family:"Arial","sans-serif";color:#111111'>Chemical challenges<o:p></o:p></span></h2>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Extracting
chemicals from waste shells with existing methods is destructive, wasteful and
expensive. It requires separating out the different components, a process known
as fractionation. Protein is removed with sodium hydroxide solution and the
decomposition of calcium carbonate uses hydrochloric acid — both are
corrosive and hazardous solvents.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>To make
chitosan, chitin is treated with 40% concentrated sodium hydroxide solution.
The production of 1 kilogram of chitosan from shrimp shells requires more than
1 tonne of water.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>As a result,
good quality chitin can cost up to $200 per kilogram, although the starting
material is cheap. The global industrial use of refined chitin (in membranes,
drug delivery, food and cosmetics) is low: around 10,000 tonnes per year</span><sup><span
style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b3"
title="Grand View Research. Amines Market Analysis By Product (Ethanolamines, Alkylamines, Fatty Amines), By Application (Crop Protection, Surfactants, Water Treatment, Personal Care) And Segment Forecasts To 2020 (Grand View Research, 2014); available at http:/"
id=ref-link-5><span style='color:#5C7996'>3</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>. Few chitin facilities exist; China,
Japan, Thailand and Indonesia have a few. The transformation of chitin or
chitosan to other chemicals poses further problems. Natural chitin is a
crystalline material that prevents reagents from easily accessing the polymer
chains. Under harsh reaction conditions, the chains easily undergo side
reactions to form myriad complex compounds. Separation of the bio-based
products from the reactor is often laborious.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>In our view,
these challenges are no greater than those in processing woody biomass into
biofuels and other chemicals, which took two decades to move from the lab to
commercial scales.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Establishing a
profitable, sustainable industry from shell waste is going to take creative
chemistry. It needs a sustainable fractionation method to separate proteins,
calcium carbonate and chitin — one that avoids corrosive or hazardous
reagents and minimizes waste.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>New
technologies are emerging. For example, teams in Mexico and the United Kingdom
demonstrated a lactic-acid fermentation process for chitin production in the
lab and in a pilot plant in the early 2000s</span><sup><span style='font-size:
9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b5"
title="Cira, L. A., Huerta, S., Hall, G. M. & Shirai, K. Process Biochem. 37, 1359–1366 (2002)."
id=ref-link-6><span style='color:#5C7996'>5</span></a>,<span
class=apple-converted-space> </span><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b6"
title="Beaney, P., Lizardi-Mendoza, J. & Healy, M. J. Chem. Technol. Biotechnol. 80, 145–150 (2005)."
id=ref-link-7><span style='color:#5C7996'>6</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>. The process converted up to
30–50 kilograms of shell waste in a single reactor. A mixture of bacteria
that consumes proteins and decomposes calcium carbonate has been developed by
groups in the United Kingdom, United States and China</span><sup><span
style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b6"
title="Beaney, P., Lizardi-Mendoza, J. & Healy, M. J. Chem. Technol. Biotechnol. 80, 145–150 (2005)."
id=ref-link-8><span style='color:#5C7996'>6</span></a>,<span
class=apple-converted-space> </span><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b7"
title="Zhang, H. et al. Carbohydr. Res. 362, 13–20 (2012)."
id=ref-link-9><span style='color:#5C7996'>7</span></a>,<span
class=apple-converted-space> </span><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b8"
title="Liu, P. et al. Biochem. Eng. J. 91, 10–15 (2014)." id=ref-link-10><span
style='color:#5C7996'>8</span></a></span></sup><span style='font-family:"Arial","sans-serif"'>.
Protein hydrolytes and calcium lactate are by-products that are useful for
animal feed and calcium supplements.<o:p></o:p></span></p>
<h2 style='margin:0in;margin-bottom:.0001pt'><span style='font-size:11.0pt;
font-family:"Arial","sans-serif";color:#111111'>Get cracking<o:p></o:p></span></h2>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Another option
would be to design and use ionic liquids (liquid organic compounds with ionic
functional groups) that can dissolve carbohydrate polymers and extract chitin.
Chitin polymers produced in this way have long chains and a high molecular
weight, and can be spun into fibres and films for wound dressings and water
treatment, for example.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Researchers
also need to explore physical, solvent-free methods for shell fractionation.
Ball milling (placing materials with metal balls in a spinning cylinder) may be
used to grind the shells finely and break apart crystals. Combining chemical
and mechanical forces might prove advantageous. For example, using a ball mill
and an acid catalyst can degrade wood without heating. Combining steam
explosion (a technique that uses superheated steam and sudden pressure release)
with acid is another way to liberate the shell's components.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Ball milling
and steam explosion have been used for woody biomass refining at a pilot scale
but few people have noticed the potential of these techniques for waste shells.
(In collaboration with the Chinese Academy of Sciences' Institute of Process
Engineering in Beijing, our group at the National University of Singapore aims
to have a pilot demonstration for shells running in a few years.)<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Converting
chitin into small nitrogen-containing chemicals — such as derivatives of
ETA and of the widely used organic solvent furan</span><sup><span
style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b9"
title="Bobbink, F. D. et al. Green Chem. 17, 1024–1031 (2015)."
id=ref-link-11><span style='color:#5C7996'>9</span></a></span></sup><span
class=apple-converted-space><span style='font-family:"Arial","sans-serif"'> </span></span><span
style='font-family:"Arial","sans-serif"'>— is developing fast, although
is still in early stages. It may take at least five years to scale up the
process and another ten years to commercialize it. Future investigations need
to explore routes from chitin to other chemicals, enhance product yields
through improved catalysis and pre-treatments and ease the separation of
products.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>We propose that
a processing pipeline be developed for refining waste shells, just as woody
biomass (composed mainly of cellulose, hemicellulose and lignin) is separated
and converted into a range of products in one facility</span><sup><span
style='font-size:9.0pt;font-family:"Arial","sans-serif"'><a
href="http://www.nature.com/news/sustainability-don-t-waste-seafood-waste-1.18149?WT.ec_id=NATURE-20150813&spMailingID=49306476&spUserID=MjA1NTE2ODQxMAS2&spJobID=741956713&spReportId=NzQxOTU2NzEzS0#b10"
title="Ragauskas, A. J. et al. Science 311, 484–489 (2006)."
id=ref-link-12><span style='color:#5C7996'>10</span></a></span></sup><span
style='font-family:"Arial","sans-serif"'>. That development took the cooperation
of many parties, propelled by public concern over energy security and climate
change. It also required financial support from governments and the chemical
and fuel industry. Shell-waste biorefineries will create new industrial
opportunities in southeast Asia and beyond.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>Strong support
from policymakers, research institutes, governments, funders and the public is
key. Fundamental research from scientists worldwide is urgently needed to
overcome the technical barriers.<o:p></o:p></span></p>
<h2 style='margin:0in;margin-bottom:.0001pt'><span style='font-size:11.0pt;
font-family:"Arial","sans-serif";color:#111111'>Shell refinery<o:p></o:p></span></h2>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>In the next five
years, a multimillion-dollar project should be launched to establish the first
processing pipeline using new technology. The project should be supported by
governments of nations rich in shell waste, and executed by researchers with
complementary expertise, covering catalysis, materials science and engineering,
food science and life-cycle assessment. Companies — including producers
and traders of shellfish, those associated with biocommodities and biomaterials
and others promoting renewable materials — should reassess the potential
markets of an environmentally friendly and profitable waste-shell refinery and
engage with research to commercialize emerging technologies.<o:p></o:p></span></p>
<p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:19.8pt;
margin-left:0in'><span style='font-family:"Arial","sans-serif"'>In the next
decade, stringent regulations should be implemented on the disposal of waste
shells, while providing incentives for companies who use them.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p>
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