The imminent need for transition to a circular bioeconomy, based on the valorisation of renewable biomass feedstocks, will ameliorate global challenges induced by climate change, environmental pollution and population growth. A reduced reliance on depleting fossil fuel resources and ensured production of eco-friendly and costeffective bioproducts and biofuels, requires the development of sustainable biorefinery processes, with many utilising macroalgae as feedstock, showing promising and viable prospects. Nonetheless, macroalgal biorefinery research is still in its infancy compared to lignocellulosic biorefineries that utilise terrestrial plants. This article presents a review on the latest scientific literature associated with the development and status of macroalgal biorefineries, and how bioproducts generated from these bioprocesses have contributed towards the bioeconomy. The fundamental need to understand how the unique biochemical composition of macroalgae fit within a biorefinery concept are explained, alongside discussion of the novel biotechnologies that have been applied. In order to comprehend the increasing significance of this exciting field, the review will also provide insight, for the first time, on the current global funding and intellectual property landscape related to macroalgae and their implementation across the entire biorefinery concept. Imperative areas for further research and development, to bridge the gap between fundamental bioscience in the laboratory and the successful application of compatible biotechnologies at a commercial scale, to boost the macroalgae industry are also covered.
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The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, but as yet there is no successful economically viable commercial system producing biofuel. However, the majority of the research has focused on producing fuels from microalgae rather than from macroalgae. This article briefly reviews the methods by which useful energy may be extracted from macroalgae biomass including: direct combustion, pyrolysis, gasification, trans-esterification to biodiesel, hydrothermal liquefaction, fermentation to bioethanol, fermentation to biobutanol and anaerobic digestion, and explores technical and engineering difficulties that remain to be resolved.
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The objective of this project was to demonstrate, at a pilot scale, the beneficial use of carbon dioxide (CO2) through a technology designed to capture CO2 from fossil-fuel fired power plant stack gas, generating macroalgae and converting the macroalgae at high efficiency to renewable methane that can be utilized in the power plant or introduced into a natural gas pipeline.
The proposed pilot plant would demonstrate the cost-effectiveness and CO2/NOx flue-gas removal efficiency of an innovative “algal scrubber” technology where seaweeds are grown out of water on specially-designed supporting structures contained within greenhouses where the plants are constantly bathed by recycled nutrient sprays enriched by flue gas constituents.
The work described in this document addresses Phase 1 of the project only. The scope of work for Phase 1 includes the completion of a preliminary design package; the collection of additional experimental data to support the preliminary and detailed design for a pilot scale utilization of CO2 to cultivate macroalage and to process that algae to produce methane; and a technological and economic analysis to evaluate the potential of the system.
Selection criteria for macroalgae that could survive the elevated temperatures and potential periodic desiccation of near desert project sites were identified. Samples of the selected macroalgae species were obtained and then subjected to anaerobic digestion to determine conversions and potential methane yields. A Process Design Package (PDP) was assembled that included process design, process flow diagram, material balance, instrumentation, and equipment list, sizes, and cost for the Phase 2 pilot plant. Preliminary economic assessments were performed under the various assumptions made, which are purposely conservative. Based on the results, additional development work should be conducted to delineate the areas for improving efficiency, reducing contingencies, and reducing overall costs. -
Algae is a very promising source for renewable energy production since it can fix the greenhouse gas (CO2) by photosynthesis and does not compete with the production of food. Compared to microalgae, researches on biofuel production from macroalgae in both academia and industry are at infancy for economically efficient and technological solutions. This review provides up to-date knowledge and information on macroalgae-based biofuels, such as biogas, bioethanol, biodiesel and bio-oils respectively obtained from anaerobic digestion, fermentation, transesterification, liquefaction and pyrolysis technique methods. It is concluded that bioethanol and bio-oils from wet macroalgae are more competitive while biodiesel production seems less attractive compared to high lipid content microalgae biomass. Finally, a biorefinery concept based on macroalgae is given. &
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In the last few decades, attention on new natural antimicrobial compounds has arisen due to a change in consumer preferences and the increase in the number of resistant microorganisms. Macroalgae play a special role in the pursuit of new active molecules as they have been traditionally consumed and are known for their chemical and nutritional composition and their biological properties, including antimicrobial activity. Among the bioactive molecules of algae, proteins and peptides, polysaccharides, polyphenols, polyunsaturated fatty acids and pigments can be highlighted. However, for the complete obtaining and incorporation of these molecules, it is essential to achieve easy, profitable and sustainable recovery of these compounds. For this purpose, novel liquid–liquid and solid–liquid extraction techniques have been studied, such as supercritical, ultrasound, microwave, enzymatic, high pressure, accelerated solvent and intensity pulsed electric fields extraction techniques. Moreover, different applications have been proposed for these compounds, such as preservatives in the food or cosmetic industries, as antibiotics in the pharmaceutical industry, as antibiofilm, antifouling, coating in active packaging, prebiotics or in nanoparticles. This review presents the main antimicrobial potential of macroalgae, their specific bioactive compounds and novel green extraction technologies to efficiently extract them, with emphasis on the antibacterial and antifungal data and their applications
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Due to diminishing petroleum reserves and deleterious environmental consequences of exhaust gases from fossil-based fuels, research on renewable and environment friendly fuels has received a lot of impetus in the recent years. However, the availability of the non-edible crops serve as the sources for biofuel production are limited and economically not feasible. Algae are a promising alternative source to the conventional feedstocks for the third generation biofuel production. There has been a considerable discussion in the recent years about the potential of microalgae for the production of biofuels, but there may be other more readily exploitable commercial opportunities for macroalgae and microalgae. This review, briefly describes the biofuels conversion technologies for both macroalgae and microalgae. The gasification process produces combustible gases such as H2, CH4, CO2 and ammonia, whereas, the product of pyrolysis is bio-oil. The fermentation product of algae is ethanol, that can be used as a direct fuel or as a gasohol. Hydrogen can be obtained from the photobiological process of algal biomass. In transesterification process, algae oil is converted into biodiesel, which is quite similar to those of conventional diesel and it can be blended with the petroleum diesel. This study, also reviewed the production of high value byproducts from macroalgae and microalgae and their commercial applications. Algae as a potential renewable resource is not only used for biofuels but also for human health, animal and aquatic nutrition, environmental applications such as CO2 mitigation, wastewater treatment, biofertilizer, highvalue compounds, synthesis of pigments and stable isotope biochemicals. This review is mainly an attempt, to investigate the biorefinery concept applied on the algal technology, for the synthesis of novel bioproducts to improve the algal biofuels as even more diversified and economically competitive. The employment of a high-value, co-product strategy through the integrated biorefinery approach is expected to significantly enhance the overall commercial implementation of the biofuel from the algal technology.
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Life cycle assessment (LCA) is a holistic methodology that identifies the impacts of a production system on the environment. The results of an LCA are used to identify which processes can be improved to minimize impacts and optimize production.
LCA is composed of four phases: (1) goal and scope definition, (2) life cycle inventory analysis, (3) life cycle impact assessment, and (4) interpretation.
The goal and scope define the purpose of the analysis; describe the system and its function, establish a functional unit to collect data and present results, set the system boundaries, and explain the assumptions made and data quality requirements. Life cycle inventory analysis is the collection, processing and organization of data. Life cycle impact assessment associates the results from the inventory phase to one or multiple impacts on environment or human health. The interpretation evaluates the outcome of each phase of the analysis. In this phase the practitioner decides whether it is necessary to amend other phases, e.g., collection of more data or adjustments of goal of the analysis. In the interpretation, the practitioner draws conclusions, exposes the limitations, and provides recommendations to the readers.
The quality of LCA of seaweed production and conversion is based on data availability and detail level. Performing an LCA at the initial stage of seaweed production in Europe is an advantage: the recommended design improvements can be implemented without significant economic investments. The quality of LCA will keep improving with the increase of scientific publications, data sharing, and public reports.
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Kelp farming, as well as the farming of various other seaweeds, is a significant and growing industry worldwide as seaweeds, especially kelp, are used for food, medicinal products, additives and bioremediation. Although the farming and use of seaweeds has a long history in many Asian and European countries, much of the rest of the world is only now recognizing the unique nutritional and health values of seaweeds. In addition to increased worldwide consumption, a recent development is the growing and harvesting of kelp for conversion to biofuels. A great deal of research is currently underway to evaluate the economics of these activities, project future demand for these algal products and to determine how best to meet increased global demand.
As the demand for kelp increases, however, relying solely on wild harvest may lead to severe declines of the natural populations such as happened in the fin fish and shellfish harvesting industries. Increased cultivation of kelp will be required to provide a consistent and traceable supply of biomass to industries that process the kelp for food or functional products. This increase in the number and size of farm sites may lead to more conflicts with fishermen, recreational boaters and waterfront land owners. These conflicts may be mitigated by an appreciation of the beneficial aspects that kelp and other seaweed aquaculture farms frequently provide such as habitat and water quality improvements.
The natural life cycle of kelp plants produces one harvestable sporophyte (adult) population per year. An advantage of farming kelp is the potential for growing more than one harvestable crop per year as well as providing the opportunity for selection of species that exhibit desired taste, vigor and resistance to biofouling.
What follows is this manual is an introduction to the processes, equipment and techniques for growing kelp from spores to harvest. Although there is significant farming of kelp worldwide, farming kelp in the Gulf of Maine has been very limited.
This manual describes the techniques developed and used successfully by Ocean Approved, LLC in conjunction with Dr. Charles Yarish and Dr. Jang Kim of the University of Connecticut to farm kelp in New England waters.
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Alaska’s burgeoning kelp farming industry has its success tied to two hatcheries and a law. Blue Evolution is working under a collaborative research and development agreement with NOAA to use the Kodiak Fisheries Research Center hatchery to grow the kelp seed that the company will supply to growers on partner farms.
“NOAA provides a space (no lease), and we capitalize the equipment,” says CEO Beau Perry. “And we work with them on various research threads.” Much of the east coast oyster industry technology was developed under this type of agreement with the NOAA facility in Connecticut in the early 1970s, Perry points out.
“Currently, there are many nascent aquaculture business across the country working with NOAA in this way,” he adds. The hatchery uses a recirculating system, and is able to utilize unused cold rooms at the facility, as opposed to water chillers. Perry estimates it has nearly 100 tanks, with capacity for several thousand spools and hundreds of thousands of feet of seeded string.
“We will certainly be pushing up against capacity as we are lowering the density of spools and tanks per cold room this season,” he explains. “But we can expand further using auxiliary space in the future.”
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Viable protoplasts were isolated from cultured thailus of agar yeilding red seaweed Gracilaria edulis using an enzyme mixture of 3% ONOZUKA R-10 cellulase 3% R-10 macerozyme, 1 % agarase and 1% pectinase in a seaweed protoplast washing medium (SPW) containing seawater and 1 M mannitol. After repeated washing wiih sterile medium, the protoplasts were maintained in light and attempts were made on electrofusion of protoplasts.
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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.