Sustainable Seaweed Technologies

Cultivation, Biorefinery, and Applications

Maria Dolores Torres, Stefan Kraan, Herminia Dominguez

• Publisher: Elsevier
• Year: 2020
• Print ISBN:
  9780128179437
• eBook ISBN:
  9780128179444
• Topic: Scienze fisiche
• Subtopic: Chimica

Sustainable Seaweed Technologies: Cultivation, Biorefinery, and Applications collates key background information on efficient cultivation and biorefinery of seaweeds, combining underlying chemistry and methodology with industry experience. Beginning with a review of the opportunities for seaweed biorefinery and the varied components and properties of macroalgae, the book then reviews all the key steps needed for industrial applications, from its cultivation, collection and processing, to extraction techniques, concentration and purification. A range of important applications are then discussed, including the production of energy and novel materials from seaweed, before a set of illustrative case studies shows how these various stages work in practice. Drawing on the expert knowledge of a global team of editors and authors, this book is a practical resource for both researchers and businesses who currently work with macroalgae. - Highlights the specific challenges and benefits of developing seaweed for sustainable products - Presents useful case studies that demonstrate varied approaches and methodologies in practice - Covers the complete seaweed chain, from cultivation to waste management

Part 1

Introduction to seaweed and seaweed biorefinery

Chapter 1

Opportunities for seaweed biorefinery

Lene Lange^a; Urd Grandorf Bak^b,c; Steffen Cole Brandstrup Hansen^d; Olavur Gregersen^b; Paulien Harmsen^e; Eva Nordberg Karlsson^f; Anne Meyer^g; Maria D. Mikkelsen^g; Lambertus Van Den Broek^e; Guðmundur Óli Hreggviðsson^{h,i a} BioEconomy, Research & Advisory, Copenhagen, Denmark
^b Ocean Rainforest Sp/f, Kaldbak, Denmark
^c National Food Institute, Technical University of Denmark, Lyngby, Denmark
^d Global Environment Facility (GEF), Washington, DC, United States
^e Wageningen Food & Biobased Research, Wageningen, The Netherlands
^f Biotechnology, Department of Chemistry, Lund University, Lund, Sweden
^g Department for Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
^h Matis, Reykjavik, Iceland
ⁱ Faculty of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland

Abstract

This introductory chapter provides an overview of seaweed biorefinery opportunities, providing basis for multiple value chains, contributing to nutrition and health of a growing global population, to local job generation and development, to ecosystem services, and not the least to climate change mitigation and adaptation. A unique and rich diversity of the seaweed components provides the basis for the broad spectrum of value-chains described here. Red, brown, and green seaweeds are phylogenetically very different and this is reflected in their differences in growth, structure, and biochemical composition. Stable supply and high quality of feedstock are essential for unlocking the value-adding potential of seaweeds. A special focus of the chapter is to provide an overview of the range of different methods of seaweed production (through cultivation or from natural growth, collected or cut at the shore). Furthermore, the results of dedicated efforts to develop new deep-sea cultivation technologies of brown seaweed are highlighted. The chapter has a dual message with regard to seaweed processing: the need to develop more environmentally benign biological processing (to replace chemical processing); the advantage (regarding resource efficiency) and opportunities (social and economic) of designing seaweed biorefineries according to the cascading principle. Making optimized use of all valuable components of seaweed biomass, cascading from high-value products, such as skin care, health-promoting food and feed supplements and functional food ingredients; to lower-value products, such as plant stimulants, soil improvers, and bioenergy. Lastly, this introductory chapter provides global perspectives for future development of sustainable seaweed utilization, contributing to the UN-SDGs, providing livelihood and health for more.

Keywords

Marine macroalgae; Seaweed biorefinery technologies; Seaweed-based value chains; CO₂ sequestration of seaweed; Climate change mitigation; Health-promoting food and feed ingredients; Blue bioeconomy

1 Seaweed and the blue biorefinery

Seaweed as a biorefinery feedstock is part of the blue bioeconomy (webgate.ec.europa.eu/maritimeforum). An important part of the objectives of the blue bioeconomy is sustainable valorization of the aquatic biomass, marine, wild catch as well as from aquaculture, to complement the terrestrial production of food, feed, nonfood (bio-materials and -chemicals) and bioenergy. Production of blue biomass does not occupy any land area and does not require use of resources such as freshwater, fertilizers, or pesticides as compared to agricultural production. The biorefinery relevant blue biomass includes besides seaweed biomass, fish-processing cutoffs and residues, fish by-catch, microalgae, and invertebrates (e.g., the protein-rich sea stars and [farmed] sea cucumber). These new types of blue biomass are promising sources of valuable components such as fucoidan and proteins (Yu et al., 2013).

Understanding the rich diversity among the three types of macroalgae (green, red, and brown) can be illustrated by observing their position in the phylogenetic evolutionary tree of life (see Fig. 1). It appears that the three types of algae are only distantly related (Yang et al., 2016), indicating that they through evolution have developed to be very different. Such differences are found not the least in their biomass composition; which again means that many different types of products can be made from macroalgae at large. Thus macroalgae represent a biomass source with a very wide use potential.

Fig. 1 Phylogenetic tree showing the position of the three major types of macroalgae, the Green, the Red, and the Brown. (Open access figure.)

2 Seaweed cultivation and harvesting from natural stocks

There are three classical ways of generating value from seaweeds. (1) Collecting the washed-up seaweed biomass on the beach, e.g., kelp or brown algae species such as Saccharina latissima, Laminaria digitata, Sargassum species, and Ascophyllum nodosum. (2) Cutting natural growth of seaweed during low tide, e.g., A. nodosum and L. digitata, brown macroalgae and species of Ulva, green macroalgae; or hand-picking species of Fucus (brown macroalgae) and Palmaria, a red macroalgae. (3) Cultivating species of macroalgae in shallow waters close to shore, such as it is done with, e.g., the red algae Chondrus crispus and Kappaphycus alvarezii. Examples of coastlines where collection of macroalgae is being practiced are the rough western coastlines include Ghana (green and brown macroalgae), France (red and brown macroalgae), Ireland (brown macroalgae/kelp), Iceland (red and brown macroalgae), and Norway (brown macroalgae). Protected shallow water, suitable for classical cultivation using wooden sticks to grow K. alvarezii, is found, e.g., in Tanzania and Zanzibar (Bindu and Levine, 2011); while in the Far East, China, Japan, Vietnam, and Thailand, the seaweed is seeded (sexual seeding) on ropes and hold in place by buoys and anchors (see also Dhargalkar and Pereira, 2005).

The local manually cultivated, harvested, washed, and sundried red algae, e.g., in Zanzibar (see Fig. 2A and B) are collected by representatives from bigger industries, who purchase the algae directly from small-hold farmers or fishing families in coastal villages. Thus, local, small-scale macroalgae biomass production is being utilized as feedstock for industrial seaweed conversion. The polymer industry typically uses chemical processing to recover specific components of the seaweed, such as different types of the polymer carrageenan. There is potential to increase production and utilize seaweed biomass grown and harvested by such classical methods as part of building a new local, coastal biorefinery sector. Thus, improved methods of protected, shallow water seaweed cultivation (including improved harvesting, washing and drying procedures) could open the way for both continued supply to larger industries and for local b...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Part 1: Introduction to seaweed and seaweed biorefinery
• Part 2: Conditioning and modification of seaweed for biorefinery
• Part 3: Extraction for seaweed biorefinery
• Part 4: Concentration and purification of seaweed extracts for biorefinery
• Part 5: Seaweed-based energy production
• Part 6: Preparation of novel materials from seaweed
• Part 7: Operations for utilization of seaweeds and/or waste solids
• Part 8: Case studies in seaweed biorefinery
• Index