Fish farming using net pens in some Japanese enclosed bays started in the late 1950s and was referred to as “the conversion of catching fisheries to rearing fisheries.” Net pen aquaculture has increased rapidly in popularity in the enclosed coastal areas of Japan since the 1970s. Total yields from net pen aquaculture recently reached approximately 270,000 metric tons, the majority of which is contributed by the culture of yellowtail, salmon, and red sea bream (Shirota 1990, MAFF 2005). A major problem of using net pens that has yet to be solved is that the fish are reared at extremely high densities with limited space and they require large amounts of food. Dissolved oxygen (DO) tends to decrease in the water in the net pens during the night due to respiration of the fish and the cessation of photosynthetic activities of phytoplankton (Hirata and Kadowaki 1990). Only 10% - 20% of the food fed to cultured fish contributes to their somatic growth. The remainder tends to be discharged as waste in the form of organic particles and inorganic nutrients outside the net pens, often causing organic enrichment of the sediment just below the fish farm and eutrophication of the water in the coves and bays where the fish farms are located (Tsutsumi and Kikuchi 1983; Hirata et al. 1994).
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Introduction
The objective of the MacroFuels project is to advance the technologies for producing liquid transportation biofuels from cultivated seaweed (or macroalgae). As a result, it is hoped that it will be possible to provide more sustainable transport fuels.
The MacroFuels concept sets out to progress the technologies for producing third generation biofuels from seaweed by assessing current system design concepts. These designs are informed by lab scale testing, field trials and modelling completed within the other work packages of the MacroFuels project. The biofuels production scenarios targeted as part of the MacroFuels concept are:
• Bio-ethanol via fermentation (EtOH process);
• Bio-butanol and bioethanol via ABE (acetone, butanol and ethanol) fermentation (ABE Process); and
• Bio-furanics via biphasic reaction with toluene and water, and reaction with bio-butanol and hydrogen.
This study reports an environmental life cycle assessment (LCA) of those biofuels which could be produced under the MacroFuels concept. The LCA evaluates the full value chain and thereby provides a better understanding of the potential environmental impacts of the large-scale cultivation of seaweed and its use as a feedstock for the production of biofuels.
A key driver for the development of biofuels in Europe is the renewable Energy Directive (2018/2001/EC) (the RED). The RED sets a target of 14% of energy for transport to come from renewable sources by 2030. For a biofuel to count towards this target, it must fulfil certain sustainability criteria set out in the RED with respect to greenhouse gas (GHG) emissions and should be identified as no / low risk for additional impacts from indirect land use change. Indirect land use change can increase the net GHG emissions from terrestrial crops used as biofuels, but seaweed is seen as a low risk crop in this context, as it is grown in the sea and will not displace land used to grow food.
Goal and Scope of the Study
The goal of this LCA was to conduct a ‘cradle-to-grave’ assessment of the MacroFuels concept. This will inform its future development by appraising the potential environmental impact of producing biofuels from seaweed for use as transport fuels and allow comparison of the calculated GHG emissions of these fuels with reported values for those produced from other sources.
The objectives of the LCA are as follows:
1. To increase MacroFuels’ understanding of the life cycle environmental impacts of the biofuels from seaweed concept;
2. Identify where the main environmental impacts occur (the so-called ‘hotspots’) in the full value chain for the production of biofuels from seaweed to support the design of systems for seaweed cultivation and processing to biofuel;
3. Compare the life cycle impacts of the ethanol, butanol and furanic fuels produced; and
4. Benchmark the biofuels assessed under the MacroFuels project against:
a. Equivalent conventional, fossil-based, fuels and currently available biofuels; and
b. Sustainability criteria for GHG emissions under the Renewable Energy Directive (2018/2001).
Product System Studied and Functional Unit
The study investigates the potential environmental impacts of the following products produced via the three processes outlined above. An important step in both the EtOH and ABE processes is the hydrolysis of the seaweed prior to fermentation. This can be completed by either acid hydrolysis or enzyme hydrolysis and both processes are considered, as follows.
• Ethanol (EtOH process - acid hydrolysis);
• Ethanol (EtOH process - enzyme hydrolysis);
• Ethanol (ABE process - acid hydrolysis);
• Ethanol (ABE process - enzyme hydrolysis);
• Butanol (ABE process - acid hydrolysis);
• Butanol (ABE process - enzyme hydrolysis);
• Furanics fuel additive; and
• Furanics fuel (10%) / bio-butanol (90%) blend
The functional unit this study is defined as:
1 MJ of biofuel used as transport fuel in an internal combustion engine.
Life Cycle Stages Considered
The LCA carried out was ‘cradle-to-grave’. This means that all significant life cycle stages associated with the product systems studied were considered, from raw materials, through processing and production, to distribution, use, waste collection, recycling or management at end of life.
Energy and material inputs were traced back to the extraction of resources, and emissions and wastes from each life cycle stage were quantified. Figure 0-1 shows the system boundary of the LCA.
Figure 0-1 System boundaries of LCA based on life cycle of biofuel from seaweed according to the MacroFuels concept
The Macrofuels concept considers a biorefinery with a processing capacity of 1.2 Mtonne seaweed (dw) per year, as this equivalent to that of an existing large bioethanol plant in the port of Rotterdam, the Netherlands.
Seaweed cultivation
The study assumes that only brown seaweed (Saccharina latissimi) is used as feedstock in the EtOH and ABE processes and only red seaweed (Palmaria palmate) is used as feedstock for the furanics process. It has been assumed that two harvests a year of these crops is possible. The cultivation systems and yields for both seaweeds are assumed to be the same.
The design of the seaweed cultivation system was based on a concept published in open literature (Groenendaal, Vandendaele, & Vroman, 2017; Sioen, 2015). The growing substrate for the seaweed is sheetnets, made from polyester non-woven material, held horizontally in the water by chains and bouys and arranged in repeating segments for a total effective area of the seaweed field of 18,460 ha. This will produce 1.2 Mtonne seaweed (dw) per year for the biorefinery.
Processing seaweed to biofuel
The data for processing seaweed to biofuel have been sourced from MacroFuels deliverable 6.2, Techno-economic Evaluation and Health and Safety Risk Assessment. Table 0-1below summarises the production processes for each scenario considered in the Macrofuels concept.
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The impact of aquaculture on the environment and effects of environment on aquaculture production have become important issues in recent years. There is evidence from many countries that environmental deterioration is a major threat to aquaculture production and product quality. There is also evidence that marine and freshwater aquaculture can cause environmental change, which in some cases may adversely affect the long-term viability of the aquaculture operation itself, or result in serious conflicts with other users of aquatic resources. These problems have led to a need to consider aquaculture as one component in the aquatic ecosystem and to plan aquaculture development in a way which makes efficient use of resources. There have been several recent reviews of impacts associated with finfish (Beveridge, 1984; NCC, 1989), mollusc (ICES, 1989; NCC, 1989) and crustacean (Phillips et al, 1990) culture but there is little information on seaweed culture.
The main environmental impacts caused by aquaculture have been reviewed in several recent publications (NCC, 1989; ICES, 1989; NCC, 1990) and can be summarised as follows:
i. physical effects, including effects on water movement, the physical structure of terrestrial and aquatic habitats and aesthetic impacts;
ii. ecological effects, including changes in water quality, primary and secondary productivity and native fisheries.
These effects have arisen in many forms of aquaculture, although impacts vary considerably depending on the nature of the culture system and species cultured, plus the environment where the culture system is located. The main impacts and problems come from intensive aquaculture with high stocking densities and supplementary feeding, but problems have also arisen in extensive aquaculture systems.
Seaweed culture has expanded rapidly over the past few years, and in 1987 3,139,473 tons (wet weight) of seaweed were produced throughout the world, the bulk produced in Eastern Asia (FAO, 1989). This expansion has brought benefits in terms of income, employment and foreign exchange, but has also been accompanied by some conflicts with other users of the coastal zone and concerns over potential environmental impacts. The aim of this review is to consider some of the environmental implications associated with seaweed culture and ways in which issues may be resolved.
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Coupling algae growth on wastewater with hydrothermal liquefaction (HTL) is regarded as an environmentenhancing pathway for wastewater management, biomass amplification, sustainable energy generation and value-added products generation. Through this integrated pathway, microalgae can not only recover nitrogen and phosphorus, but also absorb heavy metals from the wastewater. The migration and transformation of heavy metals need to be specifically assessed and considered due to the environmental concerns associated with metal toxicity. This work reviewed recent advances with respect to bioremediation mechanisms. Particular emphasis was placed on the heavy metal migration, transformation, and the key factors involved in algal wastewater treatment and biomass conversion. Additionally, the challenges of coupling algae wastewater treatment, hydrothermal conversion, and heavy metal control were addressed. Finally, a paradigm involving enhanced algal wastewater treatment and bioenergy production for field application was proposed.
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The potential of algae-based biofuels to replace petroleum fuels and mitigate greenhouse gas production through microalgal photosynthesis has long been recognized. However, currently there are no commercial algae-to-fuels technologies that can overcome techno-economic barriers and address serious sustainability concerns. Coupling microalgae cultivation with wastewater treatment is considered as one of the most promising routes to produce bio-energy and bio-based byproducts in an economically viable and environmentally friendly way. This paper critically reviews the current status of this specific niche research area covering utilization of different types of wastewaters as media for algae cultivation, microalgae selection, bioreactor type, cultivation mode, environmental factors and operational parameters as well as harvesting techniques and production of a broad spectrum of biofuels and byproducts through various conversion pathways. Future development of practical solutions to key problems and integration of advanced algae cultivation and wastewater treatment, and system analysis approach to the evaluation of economic feasibility and sustainability of wastewater-based algal biofuel production are also discussed in depth.
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The potential of algae-based biofuels to replace petroleum fuels and mitigate greenhouse gas production through microalgal photosynthesis has long been recognized. However, currently there are no commercial algae-to-fuels technologies that can overcome techno-economic barriers and address serious sustainability concerns. Coupling microalgae cultivation with wastewater treatment is considered as one of the most promising routes to produce bio-energy and bio-based byproducts in an economically viable and environmentally friendly way. This paper critically reviews the current status of this specific niche research area covering utilization of different types of wastewaters as media for algae cultivation, microalgae selection, bioreactor type, cultivation mode, environmental factors and operational parameters as well as harvesting techniques and production of a broad spectrum of biofuels and byproducts through various conversion pathways. Future development of practical solutions to key problems and integration of advanced algae cultivation and wastewater treatment, and system analysis approach to the evaluation of economic feasibility and sustainability of wastewater-based algal biofuel production are also discussed in depth.
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In fits and starts, Maine's seaweed industry is growing. Entrepreneurs are trying to create new markets for seaweed-based products, like fertilizers, pet medicines, condiments, even granola. But as harvests rise off Maine's coast, so do some concerns that the resource needs protection.
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This policy brief highlights key challenges that must be addressed for the long-term sustainability of the global seaweed industry, ensuring its role in providing nature-based solutions within the sustainable ocean economy agenda and in contributing to the UN Decade of Ocean Science for Sustainable Development (2021 – 2030).
Seaweed production has grown rapidly over the past 50 years. It currently accounts for over 50 % of total global marine production, equating to ~35 million tonnes. In 2019, the industry’s total value was estimated at USD 14.7 billion. The seaweed value chain supports the livelihoods of approximately 6 million small-scale farmers and processors, both men and women, many of whom live in coastal communities in low- and middle-income countries.
The aquaculture sector is increasingly interested in seaweed because of its potential for greater use in food, food supplements, animal feed, fertiliser and biostimulants, and in alternatives to fossil fuels and their derived products, such as plastics. Its cultivation can help restore degraded environments, increase ocean biodiversity and mitigate the effects of climate change and coastal acidification by capturing carbon and other nutrients. In low-, middle- and high-income countries, the seaweed industry has a wide-ranging potential to address the UN Sustainable Development Goals (SDGs) in particular, SDG 14 (life below water), SDG13 (climate action), SDG6 (decent work and economic growth) and SDG5 (gender equality).
The global seaweed industry, however, faces significant challenges. For future sustainability, improvements are urgently needed in biosecurity and traceability, pest and disease identification and outbreak reporting, risk analysis to prevent transboundary spread, the establishment of high quality, disease-free seed-banks and nurseries and the conservation of genetic diversity in wild stocks.
These improvements require technological innovation, capacity building and effective gender-responsive and co-ordinated policies, incentives and regulations. They will need to enhance occupational safety, whilst increasing the industry’s resilience to the impacts of climate change and production hazards, such as pest and disease outbreaks. To align with the SDGs, particular attentions will need to be paid to small scale farmers and processors to ensure that the globalisation of seaweed aquaculture supports the development of sustainable, resilient and inclusive livelihoods.
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New sources of protein are required to supplement current animal- and plant-protein. Here, we quantify the quality and yield of four protein-enriched biomass products (PEB-I to PEB-IV) and a protein isolate (PI) from the commercially produced seaweed Ulva ohnoi. To decrease the content of components of the biomass that may be undesirable in feed, we have developed a multi-step biorefinery process to produce salt, sulfated polysaccharides (ulvan), and protein products. The content of protein increased from 22.2 ± 0.4% dry weight (dw) in unprocessed biomass to between 39.5 ± 1.9% in the PEB-IV and 45.5 ± 0.8% in the PI. The quality (mol % of essential amino acids [EAA]) of the protein products was similar to soybean meal, with 41.6 ± 0.1 and 43.4 ± 0.1 mol% EAA in PEB-I and the PI, respectively. The yield of PEB products varied from 16.3 ± 0.8 to 41.0 ± 0.8% of the unprocessed biomass, with PEB-I > PEB-II = PEB-III > PEB-IV. The yield of all PEB products was more than four-fold greater than the PI (4.4%). Conservatively, the biomass productivity of U. ohnoi is 70 t dw ha−1 year−1 resulting in a projected annual production (t dw ha−1 year−1 ) of 24 t of salt, 4.3 t of ulvan, 29 t of PEB-I, or 3.2 t of PI using this biorefinery process. With nine-fold higher yield, and a protein product of similar quality to the PI, we recommend producing PEB-I by concentrating the protein through the extraction of salt and ulvan over the extraction of a PI for the development of food and feed products.
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The contribution of the DOST-PCARRD AFNR Project 2.3 from SY 2009-2011 has demonstrated transformed changes in the AFNR curriculum. These changes are well recognized as it has attracted more enrollees in the region’s dwindling AFNR courses. The study presented the implementation of the AFNR Project 2.3 in Zamboanga Peninsula as an intervention to the observed down trend enrolment in the AFNR courses since SY 2001 onwards. The AFNR Project 2.3 was implemented for the duration of two years from SY Feb 2009-Feb 2011. The project at the regional level enabled students’ preparation for employability, equipped them with entrepreneurial skills, with the integration of strong S & T contents in the courses through the modular approach. The Western Mindanao State University (WMSU) played the lead institution in the region with three collaborating SUCs, namely, JH Cerilles State College (JHCSC), Zamboanga State College of Marine Sciences and Technology (ZSCMST), and the two campuses of Jose Rizal Memorial State University (JRMSU). Towards the end of its implementation for the second year, the project achieved the following gains based on its objectives: (a) Enriched 10 BS curricular programs (b) reviewed 81 AFNR subjects (c)enriched at least 70 courses in the 10 BS AFNR Programs and (d) introduced 30 short term courses respectively.
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.