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

GROUP 6, SESSION B: METHODS, TOOLS, DATABASES 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
160. Comparison of two milk protein separation processes:
chromatography vs. filtration
Sophie Omont 1 , Daniel Froelich 2,* , François Thueux 3 , Murielle Rabiller-Baudry 4 , Didier Beudon 5 , Lionel
Tregret 6 , Christian Buson 7 , David Auffret 7 , Geneviève Gésan-Guiziou 8,9
1 ARTS, laboratoire MAPIE Chambéry, France, 2 Arts et Métiers ParisTech, laboratoire MAPIE, Chambéry,
France, 3 ECOBILAN SA, Neuilly-sur-Seine, France, 4 Université Rennes 1, UMR 6226 «Institut des sciences
chimiques de Rennes» CNRS; Rennes, France, 5 SOREDAB SA, Boissière, France, 6 Novasep Process,
Saint Maurice de Beynost, France, 7 GES, Noyal sur Vilaine, France, 8 INRA, UMR1253 STLO, Rennes,
France, 9 Agrocampus Ouest, UMR1253 STLO Rennes, France, Corresponding author. E-mail:
daniel.froelich@ensam.eu
Chromatography is the reference technology for protein fractionation at a large scale when high purity and
targeted functionality are required. Fractionation of proteins by membrane operations such as micro- and
ultrafiltration has however deserved a high attention over the last years, mainly due to their acceptable investment
and operating costs. The aim of this study is to compare the environmental performances of two
ways of fractionating whey proteins (chromatography and membrane filtration) into the two following added
value products: powder of α-lactalbumin with a 70% purity and powder of β-lactoglobulin with high purity
(> 95%) and high foaming properties. The study consists in a comparative attributional LCA, conducted
within the context of the ECOPROM project (Eco-design of membrane processes). Project carried out with
the financial support of the French national Research agency (ANR) under the Programme National de Recherche
en Alimentation et Nutrition Humaine (Project ANR-06-PNRA-015”).
The whey comes from processes commonly performed in a classical dairy: it corresponds to the aqueous
phase of milk, obtained after microfiltration of skimmed milk (Omont et al., 2010). The whey is concentrated
before its transportation into the upgrading plant where proteins will be purified and dehydrated. The system
studied includes the entire process implemented, from the entry of the whey into the upgrading plant to the
production of the two dehydrated fractions of purified proteins. The system takes into account all the
processing operations, the cleaning phases and the associated equipment. It excludes the facilities (buildings,
lighting, etc.). Its geographic scope is France. In this country, electricity is mainly produced by nuclear
power and has a low CO2 impact. As membrane processes are high electricity consumers (Notarnicola et al.
2008, European Commission 2006, Omont et al. 2010), a sensitivity analysis has been tested between French
and European electricity mixes. The inventory of the foreground system was carried out with specific data
given by the industrial partners of the project. Generic data derived from the ecoinvent V2.2 data base. The
impact assessment was calculated by the IMPACT 2002+ method using the Simapro 7.2 software. A water
flow indicator was defined for the first level processes. The “chromatography system” and the “membrane
filtration system” are described on the Table 1. The fractions outgoing from the chromatography are more
diluted. In order to generate the same concentrated α-lactalbumin and β-lactoglobulin fractions before
drying, the ultrafiltration concentrations following chromatography were resized.
Drying steps consume the same amount of natural gas for the two processes. The environmental load of the
"chromatography separation process" is mainly attributed to the ultrafiltration operations which consume
more electricity due to the resize. The Chemical Oxygen Demand contained in the non-regenerated brine and
in the column cleaning wastewater contributes to this load too, because their wastewater treatment consumes
electricity. It is noticeable that sodium chloride is not decomposed by the wastewater treatment plant; its
discharge into the water is then not assessed by the method IMPACT 2002+, which results in an underestimation
of the environmental load of the chromatography process. The environmental impact of the
"membrane filtration process" is mainly linked to the heating, the microfiltration and the ultrafiltration which
consume natural gas, electricity and water due to diafiltration. As shown in Figures 1 & 2, the environmental
load of chromatography tends to be higher than the membrane filtration. But the highest difference does not
exceed 15%. The water consumption directly linked to the processes is 25% higher in case of chromatography.
References
European Commission, 2006. Intergrated Pollution Prevention and Control, reference Document on Best
Available Techniques in the Food, Drink and Milk Industries
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