pH-shift processing of Nannochloropsis to obtain a protein-enriched food or feed ingredient Algae Biomass Summit Divisions of Food Science & Industrial Biotechnology Department of Biology and Biological Engineering Chalmers University of Technology Gothenburg, Sweden Lillie Cavonius, [email protected]2015-Oct-02
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pH-shift processing of Nannochloropsis to obtain a protein-enriched food or feed
ingredient
Algae Biomass Summit
Divisions of Food Science & Industrial Biotechnology Department of Biology and Biological Engineering Chalmers University of Technology Gothenburg, Sweden
Outline • Background: Can microalgae be processed into food? • Overview: pH-shift process • Results: solubility of Nannochloropsis protein • Results: Product characterization • Summary
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Aims
Vision • Food & feed from
Nannochloropsis • Cheap and scalable process • Minimal processing
– Wet algae (i.e. only partially de-watered)
Study • Protein solubility • Preliminary process • Characterization of product
3
The pH-shift process Isolation of proteins
+/-
OH- OH-
OH-
OH-
OH-
OH-
NH2
COO-
- -
-
- -
-
-
4
pH-shift on Nannochloropsis Protein solubility, solubilization step
0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12
perc
enta
ge o
f pro
tein
(S1/
lysa
te)
pH
5
Protein solubility, precipitation step
0 2 4 6 8
10 12 14 16 18
1 2 3 4 5
perc
enta
ge o
f pro
tein
(S2/
S1)
pH
pH 7 pH 10
pH-shift on Nannochloropsis
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Preliminary process: • Solubilization at pH 7 • Precipitation at pH 3
composition lysate pH 7/3 Dry/wet (%) 10 13
Protein/dry (%) 19 23
Total fatty acids/dry (%) 11 12
Carbohydrates/dry (%) 37 42
Ash/dry (%) 34 25
pH-shift product
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yields Protein (%lysate)
Lipid (%lysate)
P2, pH 7/3 86 85
Summary: pH-shift with seawater
• Nannochloropsis proteins – High solubility (80 – 100 %) between pH 6 and 10 – Low solubility (< 10%) below pH 4
• Process – Solubilize at pH 7 (native), precipitate at pH 3 – Removes water and ash – Conc. of protein, lipids, carbohydrates slightly increased
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Acknowledgements • Funding
– Chalmers – Kristina Stenborgs Stiftelse
• Supervisors – Prof. Ingrid Undeland – Assoc. prof. Eva Albers
Full paper: L.R. Cavonius, E. Albers, I. Undeland, pH-shift processing of Nannochloropsis oculata microalgal biomass to obtain a protein-enriched food or feed ingredient, Algal Research, 11 (2015) 95-102.
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References • Previous pH-shift on microalgae:
– J.A. Gerde, T. Wang, L.X. Yao, S. Jung, L.A. Johnson, B. Lamsal, Optimizing protein isolation from defatted and non-defatted Nannochloropsis microalgae biomass, Algal Res., 2 (2013) 145-153.
– A. Schwenzfeier, P.A. Wierenga, H. Gruppen, Isolation and characterization of soluble protein from the green microalgae Tetraselmis sp, Bioresour. Technol., 102 (2011) 9121-9127.
– M.A. Devi, L.V. Venkataraman, Functional Properties of Protein Products of Mass-Cultivated Blue-Green Alga Spirulina Platensis, J. Food Sci., 49 (1984) 24-27.
– I.S. Chronakis, Biosolar Proteins from Aquatic Algae, in: G. Doxastakis, V. Kisseoglou (Eds.) Novel Macromolecules in Food Systems, Elsevier, Amsterdam, Netherlands, 2000.
• Protein quantification method: – S.P. Slocombe, M. Ross, N. Thomas, S. McNeill, M.S. Stanley, A rapid and general method for
measurement of protein in micro-algal biomass, Bioresour. Technol., 129 (2013) 51-57. • Image sources:
– Presenting author, except for salt shaker – "Salt shaker on white background" by Dubravko Sorić SoraZG on Flickr - http://www.flickr.com/photos/
11939863@N08/3793288383/in/photostream/. Licensed under CC BY 2.0 via Commons - https://commons.wikimedia.org/wiki/File:Salt_shaker_on_white_background.jpg#/media/File:Salt_shaker_on_white_background.jpg