LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

GROUP 4, SESSION B: CROP PRODUCTION SYSTEMS 8 th Int. Conference on LCA in the
Poster session B - Wednesday, 3 October, 16.20-16.50
Group 4, Session B: Crop Production Systems
Agri-Food Sector, 1-4 Oct 2012
92. Life cycle assessment of alginate production
Juliette Langlois 1,2,* , Jean-François Sassi 3 , Jean-Philippe Delegenes 2 , Jean-Philippe Steyer 2 , Arnaud Helias 1,2
1 Montpellier SupAgro, F-34060 Montpellier cedex 2, France, 2 INRA, UR50 LBE, F- 11500 Narbonne,
France, 3 CEVA, F-22610 Pleubian, France, Corresponding author. E-mail: langlois@supagro.inra.fr
Algal polysaccharides, also called phycocolloids, are the main commercial seaweed extracts: their production
for sale reached 86,100 t over the world in 2009, considering agar, alginates and carrageenans productions
(Bixler and Porse 2010). They are mainly used in the agri-food sector, as texturing agents, stabilisers,
gel formers of film forming agents. Many other industrial applications exist, as microbiological and electrophoresis
media for agar, use in textile printing and paper coating for alginates and in toothpaste, cosmetics
and pharmaceutics for carrageenans (Bixler and Porse 2010). To our knowledge, their environmental assessment
using Life Cycle Assessment (LCA) has not been performed yet, despite this large use at industrial
scale.
We performed the LCA of phycocolloid production including seaweed cultivation. The Recipe method
(Goedkoop et al. 2009) was used, with a hierarchist perspective using the ecoinvent v2.2 database and the
SimaPro 7.3 software to carry out the impact assessment. The functional unit was to produce 1 kg of hydrocolloid.
The study is a prospective for European countries, considering pilot and semi-industrial data from
the North-Eastern Atlantic zone (data from Aleor, French seaweed producer). Bibliographic data were also
used for electricity consumption (Mafart 1997). We modeled the production of food-grade phycocolloid,
because this use is the main market for phycocolloids (Bixler and Porse 2010). Brown seaweeds are considered
due to their high growth rate potential. In the present study, seaweed was Saccharina latissima, commonly
found in this area, and reaching high alginate content, with high levels of guluronic to mannuronic
acid ratio. It was cultivated on long-lines in coastal waters, after plantlet production in nursery, as described
in Langlois et al. (2012). Seaweeds were treated straight after harvest, with common techniques of sodium
alginate production (McHugh 2003). Seaweed were first washed, crushed and treated with alcohol. After
acid lixiviation and dewatering, an alkaline extraction was carried out to solubilise alginates, followed by
dewatering using filter press. An acid precipitation with blending was then operated, followed by a last dewatering
and the addition of sodium carbonate before drying.
Contribution analysis results highlight the importance of the sodium alginate production itself (see Fig. 1).
On average on every impact categories, the seaweed production accounts for less than 1% of the total impacts,
even allowing bioremediation to marine eutrophication thanks to the nutrient uptake offshore. Electricity
is the main contributor to environmental impacts for 12 over 18 impact categories analysed, reaching 39%
of the total impacts on average. It is followed by the use of chemical (mainly because of hydrochloric acid),
accounting for 26% of the total impacts on average. Heat and cooling requirements, wastewater and waste
treatments, and the use of freshwater and mineral filter aid have only secondary impacts compared to them.
This work underlines the key elements to improve for an ecodesign of phycocolloids production.
References
Bixler, H.J., Porse, H., 2010. A Decade of Change in the Seaweed Hydrocolloids Industry. J Appl Phycol
23 (3), 321-335.
Goedkoop, M., Heijungs, R., Huijbregts, M. et al., 2009. ReCiPe 2008, a Life Cycle Impact Assessment
Method. Ministerie VROM, Den Haag, pp. 125
Langlois, J., Sassi, J.-F., Jard, G., et al., 2012. Life Cycle Assessment of Biomethane from Offhsorecultivated
Seaweed. Accepted in Biofuels Bioprod Bioref.
Mafart, P., 1997. Génie Industriel Alimentaire, Tome 1: Les Procédés Physiques De Conservation,
vol.1. Technique Et Documentation. France: Lavoisier.
McHugh, D., 2003. A Guide to the Seaweed Industry. FAO Fisheries Technical Paper, 441. Rome.
pp.118. Available online: http://www.fao.org/docrep/006/y4765e/y4765e00.htm
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