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, lillie@chalmers.se 2015-Oct-02

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

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The pH-shift process Isolation of proteins

+/-

OH- OH-

OH-

OH-

OH-

OH-

NH2

COO-

- -

-

- -

-

-

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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

•  Colleagues at –  Food & Nutrition Science –  Industrial Biotechnology

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

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Amino acid profile lysate P2, pH 7 lysate

P2, pH 7

mg/g mg/g mg/g mg/g sum 235 265 sum non-essential 137 151 sum essential 97 114 Alanine 16 18 Lysine 15 18 Arginine 15 17 Methionine 4,3 5,5 Aspartic acid 21 24 Phenylalanine 12 14 Cystein + Cystine 2,5 2,7 Proline 24 22 Glutamic acid 26 29 Serine 11 12 Glycine 14 15 Threonine 12 13 Histidine 4,4 5,5 Tryptophane (total) 4,1 4,8 Isoleucine 10 12 Tyrosine 8,8 10 Leucine 20 24 Valine 15 17

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Fatty acid profile

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lysate, pH 7 P2, pH 7 mg/g mg/g

sum 105 123 C12:0 0,3 0,4 C14:0 5,5 6,7 C15:0 0,4 0,4 C16:0 29 34 C16:1 n7 32 37 C17:0 0,3 0,4 C17:1 0,3 0,4

lysate, pH 7 P2, pH 7 mg/g mg/g

C18:0 0,4 0,5 C18:1 n9 7,9 9,5 C18:1 n7 0,4 0,5 C18:2 n6 3,5 4,2 C18:3 n6 0,4 0,5 C20:4 n6 5,2 6,2 C20:5 n3 19 23

pH-shift on Nannochloropsis •  Lipid partitioning, pH 7

•  Lipid partitioning, pH 10

S1

P1

P2

S2

S1

P1

S2

P2

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