Final Report Summary - MABFUEL (Marine Algae as Biomass for Biofuels)
Project Concept and Objectives:
The main aim of this project was to investigate the feasibility of using algae (micro and macro) as a feedstock for producing bio-fuels in Turkey and Ireland.
Work performed and main results:
Oil yield and fuel characteristics of selected wild seaweeds species from different sites of Ireland (15 species) and Turkey (14 species) and in different seasons (for two years) were investigated by Soxhlet extraction with n-hexane. In addition, Alaria esculenta was cultured around a salmon farm in order to assess its bio-remdiation potential. Dictyota species collected from Mediterranean Sea in May 2011 had the highest oil content (8.01% dry wt. basis) for Turkey. For Ireland, Bifurcaria bifurcata species collected from Bantry Bay in June 2011 had the highest oil content (5.90% dry wt. basis). There was no significant difference for the other species. Highest oil content was always obtained in summer. Drying type slightly effected on the oil yield. Cultured seaweed grown adjacent to a fish farm had a significantly higher biomass than the control site. However, seaweeds are not ideal for bio-fuel production as higher overall amounts would be needed. FAME analysis was performed using GC-FID. Extracted seaweed oils had higher amounts of PUFAs than SFAs. So they are not desirable for fuel characteristics.
Selected microalgae species were grown in a photobioreactor at DOMMRS, both in indoor and outdoor tanks. Oil yield and fuel characteristics were determined. Phaedactylum tricornatum had the highest specific growth rate but Nannochloropsis oculata and Nannochloropsis salina had highest oil content with 20.83% and 13.91% dry wt. basis respectively. Temperature fluctuations was limiting factor for outdoor cultivations. Harvesting the algae was the biggest issue as the cell size ranges from 2-12 microns so centrifugation was needed to separate the algal cells from the water however the energy requirement for this can be excessive therefore experiments were conducted in order to reduce the energy needed in harvesting. Nutrient stress condition (N deprivation) increased the lipid production. Super critical carbon dioxide extraction was also investigated. Extracted microalgae oils had higher amounts of MUFAs which is desirable for fuel characteristics.
Work also was conducted on extraction methods. At Gaziantep University the samples were pretreated to maximise extraction of oil. This was done by; enzymatic extraction, osmotic shock, ultrasonic treatment, extrusion technology and ozone. The samples were then sent to Ege University for further extraction and analysis. At Ege University work focused on the pyrolysis, hydrogen and methane production. An economic and environmental risk assessment was also conducted which included a SWOT analysis and consumer survey.
• A reduction in green house gas emissions from the product/s developed.
• Bio-fuel is a renewable source of energy.
• The bio-fuel product can be produced domestically and thus contribute significantly to the economy.
• The product will help to meet the government target for bio-fuel production (EC Directive 2003/30)
• Certain species have a higher energy rate compared to conventional bio-fuel crops.
• Certain species have a higher biomass per ha and faster growth rate than terrestrial bio-fuel crops.
• Space is not a limiting factor in growing algae.
• Enhancement of the skills and knowledge of both researchers and non-scientific staff.
Role and Contacts
1.Daithi O’Murchu Marine Research Station - Contact: firstname.lastname@example.org
2. Green Biofuels Ireland Ltd
3. Queens University, Belfast
4. Dundalk Institute of Technology
5. Gaziantep University
6. Ege University
7. Irish Seaweeds Ltd