Authorship

The section on the optimal production of fish protein hydrolysate was developed by

Carmen González Sotelo and María Blanco Comesaña from the Institute of Marine Research, CSIC, Spain.

Figures

Figure 1: Structure of the most frequent amino acids in collagen (A). Peptide bond formation (B). Shows the structure of the most frequent amino acids which are present in collagen  and which are Glycine; Proline and Hydroxyproline (A). Peptide bond formation between amino acids (B). it was created by Carmen G. Sotelo of the Institute of Marine Research, CSIC. It is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 2: Structure of a fibrous (A) and a globular protein (B). Structure of a fibrous protein (A): group to which belongs the collagen molecule; and a globular protein (B) which is a different type of protein with a different structure compared to fibrous one. Created by Carmen G. Sotelo of the Institute of Marine Research, CSIC. It is licensed under Creative Commons 4.0 cc-by-nc-sa

Figure 3: Marine organisms and tissues containing collagen. Shows different images of marine organisms and/or tissues containing collagen. Created by María Blanco and Carmen G. Sotelo of the Institute of Marine Research, CSIC. It is licensed under Creative Commons 4.0 cc-by-nc-sa

Figure 4: Parallel arrangement of collagen fibres showing fibroblast responsible of collagen synthesis (A). TEM image of cross and longitudinally section of fibrils showing the characteristic repeating banded pattern (B). Illustration (A) was provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC. It is licensed under Creative Commons 4.0 cc-by-nc-sa. Illustration (B) is reproduced from http://histology.med.yale.edu/connective_tissue/connective_tissue_reading.php

Figure 5: Freeze-dried fish collagen (A); Electron microscopy fibrils (B); Assembly of triple helix collagen structure (C). Image showing a piece of freeze-dried fish collagen (A); an electron microscopy image of that piece of freeze-dried fish collagen fish showing macroscopic fibrils (B); draw showing the assembly of triple helix collagen structure from the tropocollagen molecule to the complex fibrils (C). Created by María Blanco of the Institute of Marine Research, CSIC. It is licensed under Creative Commons 4.0 cc-by-nc-sa

Figure 6: Fibril-forming collagen. Collagen type I² (A); Basement membrane collagen. Collagen type IV³ (B). Parallel arrangement of collagen fibres showing fibroblast responsible of collagen synthesis (A). TEM image of cross and longitudinally section of fibrils showing the characteristic repeating banded pattern (B). Illustration (A) is redrawn from http://atlasgeneticsoncology.org/Genes/GC_COL1A2.html. Illustration (B) is adapted from Hudson, B. G., Tryggvason, K., Sundaramoorthy, M., & Neilson, E. G. N. Engl. J. Med. 2003, 348(25), 2543–2556.

Figure 7: Typical stress–strain curve/deformation mechanism of collagen-based devices depicting the four distinct regions: the toe region (1), the heel region (2), the elastic region (3) and the failure region. Redrawn by María Blanco Comesaña and Carmen G. Sotelo from: Sorushanova, A.; Delgado, L. M.; Wu, Z.; Shologu, N.; Kshirsagar, A.; Raghunath, R.; Mullen, A. M.; Bayon, Y.; Pandit, A.; Raghunath, M.; et al. The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development. Adv. Mater. 2019, 31 (1), 1–39.  It is licensed under Creative Commons 4.0 cc-by-nc-sa

Figure 8: Atlantic Salmon (Salmo salar) by-products: skin (A), trimming and frames (B); heads (C) used for collagen extraction and characterization. The photographs were provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and are licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 9: MW: molecular weight standard (kDa) 1. Salmon skin 2. Turbot skin 3. Turbot trimmings 4. Turbot head 5. Rainbow trout skin 6. Rainbow trout trimming and frames 7. Seabream skin 8. Seabass skin. The image of Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis of collagen was provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 10: GPC-LS of type I collagen obtained from fish skin by-products. Red line indicates refraction index value. Blue line indicates LS values. This image was provided by María Blanco of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 11: Fish collagen iEX-HPLC elution profile showing alpha 1 chain and beta components. This image was provided by María Blanco Comesaña and Carmen G. Sotelo of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 12:  RP-HPLC of collagen from turbot aquaculture skin by-products. A reverse phase-HPLC of collagen from turbot aquaculture skin by-products showing different hydrophobicity of collagen components.This image was provided by María Blanco of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 13:  FTIR spectra of acid soluble collagen (ASC) extracted from fish by-products. Illustration provided by Carmen G. Sotelo and María Blanco Comesaña of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 14: Fishery by-product valorization for fishmeal production. Illustration provided by Carmen G. Sotelo and María Blanco of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 15: Valorisation strategies and added value. Redrawn by María Blanco Comesaña and Carmen G. Sotelo from: Barbier, Michèle & Charrier, Benedicte & Araujo, R. & Holdt, Susan & Jacquemin, Bertrand & Rebours, Celine. (2019). PEGASUS SUSTAINABLE SEAWEED AQUACULTURE 9 May 2019. http://doi.org/10.21411/2c3w-yc73 and is licensed under Creative Commons 4.0 cc-by-nc-sa. The original figure (9) was adapted from Day et al 2016.  The source publication is also licensed under Creative Commons 4.0 cc-by-nc

Figure 16: By-product yields for turbot (S. maximus) (A). Comparison of by-product yields in different aquaculture species (B). The images were provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and are licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 17: Steps for collagen extraction from salmon skin.  The images were provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and are licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 18: Complete procedure for collagen extraction from salmon skin developed at IIM-CSIC. The illustration was provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 19: Nanoemulsions prepared with fish skin by-products collagen hydrolysates. The illustration was provided by María Blanco of the Institute of Marine Research, CSIC, and are licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 20: Fish collagen-chitosan composites (A) and fish collagen hydrogels (B) for dermatological or tissue engineering applications. The illustrations were provided by María Blanco of the Institute of Marine Research, CSIC, and are licensed under Creative Commons 4.0 cc-by-nc-sa.

Figure 21: Antiwrinkle and hydrating cosmetic product prepared with fish collagen hydrolysate. The illustrations were provided by María Blanco of the Institute of Marine Research, CSIC, and are licensed under Creative Commons 4.0 cc-by-nc-sa.

Tables

Table 1: European (EU and EEA) aquaculture fish species categorized by production volumes, systems, and country. Adapted by María Blanco Comesaña and Carmen G. Sotelo from: FAO. 2020. El estado mundial de la pesca y la acuicultura 2020. La sostenibilidad en acción. Roma.

Table 2: Amino acid content (residues per 1000 residues ± Standard Deviation) of Type I skin collagen extracted from Atlantic salmon (Salmo salar) skin by-product. The table was provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.

Table 3: Collagen extraction yields obtained from different fish species by-products.  The table was provided by Carmen G. Sotelo of the Institute of Marine Research, CSIC, and is licensed under Creative Commons 4.0 cc-by-nc-sa.