WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 59 make such operations impractical. Thus, most attention has focused on offshore cultivation of local seaweeds, with a popular candidate species being Laminaria japonica, the most common seaweed currently used for food and chemical production, considered thirty years ago for such applications (Tseng 1981, Chynoweth 2002, 2005). In Ireland, Laminaria and Ulva are being considered because of their relatively high carbohydrate content (Bruton et al. 2009). Ulva can be readily digested to methane gas and seem to lack epiphytes, such as microalgae growing on the surface of the seaweed thallus that can interfere with their production (Chynoweth 2002, 2005). Other species also evaluated for fuel production in the 1980s include Gracilaria tikvahiae (a red algae species), notable for its high yields in onshore cultivation tests (Hanisak 1987). Another interesting macroalga is Sargassum, a brown macroalgae species (Chynoweth 2002, 2005). A few examples of recent projects initiated are: China. Sustained commercial cultivation of macroalgae has successfully been conducted with Laminaria japonica which showed yields of about 25 t ha-1 (Bruton et al. 2009). Japan. The Ocean Sunrise Project developed Sargassum fulvellum cultivation and its conversion to ethanol production in unused maritime areas around Japan (Aizawa et al. 2007). This Project also plans to adapt farming technology used for Laminaria and Undaria pinnatifida in coastal zones to offshore areas, with rope cultures configured as a trawl net. Tohoku University and Tohoku Electric Power Company claim to have discovered a natural yeast for conversion of macroalgae into ethanol. After two weeks, the conversion rate was 200 mL of ethanol from 1 kg of macroalgae. Korea. The Korea Institute of Industrial Technology have reported the saccharification and conversion of Gelidium amansii into ethanol (Yoon et al. 2010). India. The Central Salt and Marine Chemicals Research Institute has produced ethanol from Kappaphycus alvareziii. Indonesia. The Korea Institute of Technology and partners have developed macroalgae cultivation to provide biomass for ethanol production, leasing 25,000 ha of coastal waters for this project. Similarly a project under the South Korea National Energy Ministry plans to create a 35,000-ha offshore macroalgal forest for producing ethanol. Brazil. The State of Rio Grande do Norte Agricultural Research Company (EMPARN) is developing large-scale production techniques for fuel from macroalgae. USA. At the University of Maine, there is a project on the life cycle assessment of macroalgae for biofuel and the study of the conversion of Algefiber® from Eucheuma spinosum into carboxylic acids to be converted into alcohol fuels. Denmark. Scientists are applying similar ethanol conversion technology from Horn et al. (2000) to the green algae Ulva lactuca which is abundant in their area (Huesemann et al. 2010). Germany. For offshore farming, scientists investigated an offshore ring system for Laminaria saccharina (Buck and Buchholz 2004). The design is for food production but can also be used for fuel. UK/Ireland. The Sustainable Fuels from Marine Biomass Project (BioMara) plans to investigate the economics and feasibility of using macroalgae for methane and ethanol production. Macroalgal Resources of Turkey The macroalgal resources of Turkey are very rich, with approximately 1000 species of macroalgae within the classes of red macroalgae (Rhodophyceae, 60 percent), brown macroalgae (Phaeophyceae, 21 percent) and green macroalgae (Chlorophyceae, 19 percent). Of these, Gracilaria, Gigartina, Hypnea, Porphyra, Asparagopsis, Sargassum, Cystoseira, Dictyopteris, juvenile Laminaria (Petalonia), Ulva and Caulerpa have the greatest potential for intensive macroalgae cultivation in Turkey. Intensive farming of macroalgae is a new concept in Turkey, unlike East Asia, where intensive cultivation of macroalgae is documented from the 17th century. The farming situation in China, Korea and Japan is on a much larger scale, with more than 100,000 ha of cultivation areas in Japan alone, employing more than 30,000 people. Macroalgae production in Turkey is small, at around 45 t annually of harvested natural stocks. However, Turkey is rich with the resources required for a very large macroalgae industry that will undoubtedly expand in the coming years. Conclusions The aquacultural, ecological, engineering, economic and social challenges remaining to be solved are for some maybe daunting. However, the goal is to develop modern offshore macroalgae-based IMTA systems, which are bound to play a major role worldwide in sustainable expansion of future aquaculture operations, within a balanced ecosystem or eco-friendly approach, to respond to global increases in seafood demand with a new paradigm in the design of the most efficient food, feed and fuel production systems. Offshore macroalgae-based IMTA has enormous potential for growth in Turkey where there are active research programs gaining knowledge about their potential. As a result of established production practices, habitat appropriateness, biomitigation ability and economic value, Gracilaria, Gelidium, Gigartina, Hypnea, Porphyra, Asparagopsis, juvenile Laminaria (Petalonia), Sargassum, Cystoseira, Dictyopteris, Ulva and Caulerpa are recommended for development in offshore IMTA systems in Turkey. To some extent, macroalgal biomass can contribute to global renewable bioenergy, such as methane, ethanol and butanol and biobased products, and desired products for aquafeeds. The timely transition to renewable fuels and biobased products from macroalgae critically depends on progress in several areas, including: • Establishing the economic value of offshore macroalgae-based IMTA systems and their co-products, • Developing bio-economic models for offshore macroalgaebased IMTA systems, • Exploring additional economic value for offshore macroalgaebased IMTA co-products, • Exploring CO2 utilization against global warming by offshore macroalgae-based IMTA coproducts, • Selecting the appropriate species and habitats, • Promoting effective government legislation/regulations and incentives for offshore macroalgae-based IMTA developments and commercialization of products, • Recognizing the benefits of offshore macroalgae-based IMTA and educating stakeholders about this practice, and • Establishing research, development and commercialization for offshore macroalgae-based IMTA. (CONTINUED ON PAGE 60)
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