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Seaweeds: a multi-purposed bioresource well-suited for Integrated Sequential BioRefinery (ISBR) processing

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For the last seven decades, westerners have been eating/
using seaweeds without really knowing it because it
has been through extracts known as phycocolloids – the
gelling, thickening, emulsifying, binding, stabilising,
clarifying and protecting agents known as carrageenans and agars
(extracted from red seaweeds) and alginates (extracted from brown
seaweeds) – used in the food, brewing, textile, pharmaceutical,
biotechnological, coating, drilling, etc industries.
Why is your ice cream smooth and not full of big ice crystals?
It contains carrageenans! The cocoa powder of your chocolate
dairy drink is not all at the bottom of the bottle and you believe the
product has not been on the shelf long: the microscopic carrageenan
mesh did it again! Green olives with pimento strips inserted in the
pit hole? Sorry, these strips are made of a carrageenan paste with a
colorant and antioxidant (asthaxanthin from microalgae) and two
drops of articial pimento avor! For fast relief of heartburn, you
can take alginate tablets or liquids, which block acid reux from
your stomach. Some breweries have a clarifying step for your beer
that involves the red seaweed called Irish moss.
Fine printing on textile/silk is only possible if the material has
been soaked in a carrageenan or alginate solution, which will then
keep the dye in place. All the DNA analyses used to identify who
did the crime on the CSI television series: banding patterns on agar
gels! How is the gyprock in your garage ame-retardant certied? It
is coated with alginates. Wonder why the water does not go through
the paper goblets of your water fountain at work? They are coated
with carrageenans. Underground drilling is quite tough on bits; they
need to be cooled down with alginate mud.
An evolving industry
The phycocolloid sector, however, now represents only a minor
part (11.4% of the tonnage and 10.8% of the value) of an industry
in full mutation. The worldwide seaweed aquaculture production
in 2016 was 30.1 million tonnes, worth US $11.7 billion, and
represented 96.5 percent of the world seaweed supplies.
The use of seaweeds as sea-vegetables for direct human
consumption has become much more signicant (77.6% of the
tonnage and 88.3% of the value). Five genera dominate the edible
seaweed market: Saccharina and Laminaria (kombu), Undaria
(wakame), and Porphyra and Pyropia (nori). If the use of seaweeds
as edible human food is well-established in Asian countries, a lot
of work is still needed to educate westerners regarding cooking
with seaweeds and going beyond the superfood fad, to have them
understand the benets of including these crops in their regular
diet.
The phycosupplement industry is a fast-emerging component
(11.0% of the tonnage and maybe an underestimated 0.9 percent of
the value). This includes soil additives, agrichemicals (fertilizers
and biostimulants), animal feeds (supplements and ingredients;
increasingly for aquaculture), ne and bulk chemicals, small
biopolymers, pharmaceuticals, cosmetics and cosmeceuticals,
nutraceuticals, functional foods, biooils, health anti-applications
(anti-oxidants, anti-cancer, anti-microbial, anti-viral, anti-
inammatory, anti-diabetic, etc.), botanicals, pigments, colorants,
aromatics, brewing components, biomaterials/biocomposites,
thermoplastics, adhesives, etc.
Seaweeds are prime candidates for integrated sequential
biorenery processing
For too long, seaweeds, like other shery and aquaculture
products, have been processed according to a simple scheme: one
species - one process - one product. However, seaweeds remain a
relatively untapped resource with a huge potential for integrated
sequential biorenery (ISBR) processing (Figure 1).
We will have to change our attitudes
and business models to evolve from this
linear approach to move towards the ISBR
approach (one species - several processes
- several products) within a circular
economy framework, where there are no
longer wastes and by-products, but co-
products, which can also be marketed.
With careful planning at the time
of harvesting, and with sequential
processing, more than one product can
be manufactured from seaweeds: on one
hand, a wide range of bio-based, high-
value compounds (cited above); on the
other hand, lower-value commodity energy
compounds (biofuels, biodiesels, biogases,
bioalcohols, aldehydes, acids, heat/steam
and power/electricity generation, etc.).
We have already adopted this ISBR
diversication approach with our own
Integrated Multi-Trophic Aquaculture
(IMTA) products, focusing on those
Seaweeds: A multi-purposed bioresource
well-suited for Integrated Sequential
BioRenery (ISBR) processing
Dr Thierry Chopin
Figure 1
14 | November 2018 - International Aquafeed
of the rst type: seaweeds for human consumption, beer,
cosmetics, nutraceuticals, pharmaceuticals, partial shmeal
substitution, organically-certied IMTA kelps, and kelps for
biochar production as a substrate for freshwater IMTA (or
aquaponics).
We have stayed away from the biofuel bandwagon, as things
do not add up. It is doubtful that the surface area needed to
secure the raw material for signicant biofuel production will be
societally acceptable, especially in the western world. Seaweed
biomass production is highly seasonal, while people rell at
gas stations 52 weeks of the year. Scaling up from laboratory
experiments to commercial markets needs reality testing.
Moreover, to be economically competitive, seaweed biofuel
would have to be at least as cheap as the fossil biofuel presently
used, i.e. petroleum.
We have no interest in trying to sell seaweeds at several cents/
tonne fresh weight (FW) when we cannot produce them that
inexpensively. On the contrary, we are interested in a spectrum of
products ranging from a few $/kg FW (phycocolloids, fertilizers
and feed), to several tens of $/kg FW (human food and ne
chemicals), to around 100 $/kg FW or more (pharmaceuticals,
nutraceuticals and cosmeceuticals).
Optimising the entire value chain
Many steps before (cultivation, harvesting, dewatering, pre-
treatment, transportation and storage) and during (separation,
fractionation and sequential processing) the different
technological pathways of an ISBR still require elucidation and
sustainability assessment.
The processing steps to extract, separate, fractionate and
purify multiple products will have to be eco-, chemico- and
enzymatico-friendly. In order to not denature products obtained
later, mild extraction conditions will have to prevail at the
beginning of the process, to then move to moderate and harsher
extraction conditions at a later stage on subfractions, if needed.
Functionalities will have to be maintained, as much as
possible, along the process for optimal use/valorisation of the
multi-purpose biomass, and not necessarily the maximisation
of just one end-product, as some co-products could reveal
themselves to be the real drivers of the emerging ISBR
concept.
To optimise the integration of bioreneries, aquaculturists
and the different multi-sector end users will need to become
inter-disciplinary in their approach. They will have to learn
to collaborate and share/integrate the biomass cultivation and
processing steps (production, harvesting, pre-treatment and
transportation, separation and fractionation, and sequential
biomass processing), while aiming at the lowest resource and
energy inputs.
Market volumes/values, ecosystem services, and public
acceptance will have to be considered and included in the
business models.
Dr. Thierry Chopin is Professor of Marine Biology, and Director of the Seaweed and Integrated
Multi-Trophic Aquaculture Research Laboratory, at the University of New Brunswick in Canada.
He is also the President of Chopin Coastal Health Solutions Inc. since 2016.
International Aquafeed - November 2018 | 15
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News
... Around 500 species have been used for centuries for human food and medicinal purposes, either directly as food ( primarily within Asian countries; MacArtain et al. 2007;Pereira 2011;Tacon and Metian 2013) or indirectly for the compounds that can be extracted from them (e.g. phycocolloids such as agars and carrageenans extracted from red seaweeds and alginates extracted from brown seaweeds) (Chopin 2018b). Although over 220 species of seaweeds are reportedly cultivated worldwide, only 20 species were listed in the FAO FISHSTAT database for 2018 (FAO 2020b). ...
... Value of the seaweed aquaculture sector FAO indicates a farm-gate value of US$13.3 billion for the world seaweed aquaculture production (FAO 2020a). Estimating the true value of the different seaweed markets is difficult, as seaweed applications are numerous (Chopin 2018b) and some lucrative emerging markets are presently in full expansion while others need to be further developed. ...
Article
Full-text available
The FAO recently published its biennial State of World Fisheries and Aquaculture up to 2018. The FAO continues to treat the seaweed aquaculture sector as a different category, with separate tables and comments in different sections. As this could lead to a distorted view of total world aquaculture, the statistical information provided by FAO was revisited and data regarding the seaweed aquaculture sector were integrated with data of the other sectors of the world aquaculture production, to reach different conclusions: 1) aquaculture represents 54.1% of total world fisheries and aquaculture production; 2) marine and coastal aquaculture represents 55.2% of total world aquaculture production; 3) seaweeds represent 51.3% of total production of marine and coastal aquaculture; 4) 99.5% of seaweed mariculture production is concentrated in Asia; 5) 8 seaweed genera provide 96.8% of world seaweed mariculture production; 6) 2 seaweed genera are the most produced organisms in mariculture in the world; 7) the value of the seaweed aquaculture sector could be much larger, especially if a monetary value was attributed to the ecosystem services provided by seaweeds; and 8) total extractive aquaculture is slightly larger (50.6%) than total fed aquaculture (49.4%).
... Emerging biorefining techniques, with sequential extraction of products, are likely to markedly increase cost-effectiveness and scale of production (Chopin 2018a;Sadhukhan et al. 2019). The possibility also exists to develop more offshore, integrated multitrophic aquaculture, including seaweed aquaculture, in the open ocean (Buck et al. 2018). ...
Article
Full-text available
ABSTRACT Finding ways to keep global warming under 1.5 degrees Celsius is urgent and will need a portfolio of solutions. Seaweeds are marine photosynthetic organisms that humans harvest either from the wild or farm, to be used in many applications and providing various ecosystem services. large scale farming of seaweeds for absorbing carbon has lately been promoted as a climate "fix". the major shortcomings of this argument relate to the idea that a carbon sink function should exist through carbon accumulation in seaweed biomass simultaneously as seaweeds are consumed as food by humans, fed to animals, or used in many alternative applications. this carbon instead enters the fast carbon cycle and does not provide any "carbon sink" function. radical suggestions of intentionally transfer of farmed seaweeds to the deep-sea to accomplish a longer removal are highly questionable from feasibility, economic, ecosystem effects and ethical resource use perspectives. development of "ocean forests" for carbon capturing through farming should not be compared to forests on land as these provide carbon removal from the atmosphere at sufficiently long time scales to be qualified as carbon sequestration-thus making a difference related to reducing atmospheric greenhouse gas concentrations. Seaweeds can, however, play a role in reducing greenhouse gas emissions from the overall food system through carbon offset-i.e. if replacing food, feed, and/or materials that have larger carbon footprints. the fate/cycling of carbon as particulate and dissolved matter from both farmed and wild seaweeds, are however not fully understood, especially with respect to pathways and time scales relevant for carbon removal/storage. another potential pathway for their role in decarbonization may be through reducing enteric methane emissions from ruminants and also through bioenergy production. More research is, however, needed for understanding the contributions from such interventions. Presenting seaweed farming as a quick fix for the climate risks facilitating misdirected investments (for carbon abatement solutions) and reducing demand for specific research and technological development that will be needed for increasing our understanding about seaweeds' contribution to food/feed systems and additional sustainability services and benefits.
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