Biofuel Production Using Microalgae - DENSO

1 59 60 * Biofuel Production Using Microalgae Norihide KURANO Hiroaki FUKUDA Masao NAGAKUBO Kinya ATSUMI Microalgae belong to the plant family, carry out photosynthesis, convert inorganic substances into organic substances, and produce hydrocarbons and neutral lipids. The resulting products can be directly or indirectly used as biofuels . Compared with Biofuel Production by terrestrial higher plants, Microalgae cultivation does not compete with food Production . Furthermore, the Biofuel productivity and CO2 fixation ability of Microalgae are much greater than those of higher plants. As a result of these benefits, numerous start-up companies in the US have attracted the attention of venture capitalists. Currently, microalgal biofuels are less cost competitive than fossil fuels. Therefore, cost cutting efforts, for example, the development of biorefineries, the optimization of culturing methods, the genetic improvement of oil productivity, etc, are indispensable to the practical realization of microalgal CO2 fixation and Biofuel Production systems.

2 Key words: Microalgae , Biofuel , CO2 fixation 2009 9 28 . International Energy Outlook 2009 .1) , 2030 200 , 130 , 50 . , 2020 .2) .. , , CO2 , . , . 10 CO2 , CO2 . R&D , , .. , , , .3) . , . , 1950 , 1980.

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4 CO2 CO2 , , , , , , , CO2 LC-CO2 , . , IntroductionDinophyta (Alveolate)HaptophytaChromophytaCryptoph ytaRhodophyta (Red algae)GlaucophytaSecondary endosymbiosisAncestral heterotrophic eukaryotesSecondary endosymbiosisPrimary endosymbiosis?ChlorophytaEuglenophytaChl orarachniophytaFig. 1 Introduction to evolutional history of algae 61 62 , , 50 g CO2 . , , , . CO2 5g-CO2 m-2 d-1 , 10 ..6) . , Table 1 , , .. , . CO2.

5 , .. , . , BDF . , BDF , . , , , . , 40 ,7) 1970 SERI, NREL National Renweable Energy laboratory , DOE Aquaic Species Program-Biodeisel from Algae APS , raceway pond ,8) R&D . RITE , 10 R&D . 2007 . W 2017 350 , . , DOE , , Sonora Fields Algenol 850M , ExxonMobil Synthetic Genomics 600M , venture captals Sapphire Energy 100M.

6 CREST Botryococcus 2008 . CREST Botryococcus , Botryococcus R&D . Doubling(h) lightsolar irradiationHigher plants(crops)120(maize) (average forest) 2PE(%)CO2 fixation(g-CO2 m-2 d-1)PE: Conversion efficiency from photosyntheticlly active radiation to chemical energyCyanobacteria: Cyanobacterium sp. MBIC10216 Table 1 Growth characteristics of typical photoautotrophs 61 Vol. 14 2009 62 , .. Fig. 2 .. CO2 .. , , . , driving force.

7 , . Botryooccus braunii9) , 30 70 , . , . , , , .. Pseudochoricystis ellipsoidea Fig. 3 2003 . Botryococcus 17-20 . 30 , 2/3 BDF . WO2006/109588 , . , . , , , . RITE , CO2 50 g-CO2 m-2 d-1.

8 , DOE APS raceway open pond . , CO2 Table 2 . , Fig. 3 A unicellular green alga, Pseudochoricystis ellipsoidea MBIC112041010210310448006842304617 SoybeanPhotovoltaic cellMicroalgaePalmRapeseedFig. 2 Comparison of energy Production by biodiesel producing plants (GJ ha-1 year-1)a)b) a) Micrograph of P. ellipsoidea, bar = 5 m. b) Fluorescence micrograph, yellow particles indiacte oil droplets, and red color indicates chlorophyll autofluorescence. 63 64 raceway 11th International Conference on Applied Phycology . , .. , , . raceway , , , , . , raceway . raceway.

9 , , .. Fig. 4 , kg 285 , 30 950 /kg . , , , , . , , , , . , , . , . , , , . , . , .. , . , , waterinletairoutputports forvarious sensorssamplingportairoutletwateroutletp ort for airtubingculturechambertemperatureregula tionchamberwaterinletFacilityOpen-typeRa ceway 5057 60 ( )?670(42%)110 120(10%)180(14%)1214(75%)10351170386 TubularFlat panelClosed-typeProductivityMaintenanceP roductivityEnergy lossEnergy productionBiomass (t/ha year)Energy (GJ/ha year) (GJ/ha year)Mixing (GJ/ha year) (%)Total (GJ/ha year) (%)Table 2 Energy productivity and easiness of maintenance of three different culture facilities300250200150100500-50 DepreciationTotal 285/kg dry biomassTreatment cost( /kg dry biomass)Labor chargeOil extracrionCell harvestingCultivationFig.

10 4 Process analysis for cost of microalgal biodiesel Production 63 Vol. 14 2009 64 1) Fig. ) ) (1999) ) L. Sagan, J. Theoretic. Biol., 14 (3) (1967), ) R. H. Whittaker (1975) ) 79 (10) (2001), ) CO2 (2006), ) ) , Fig. 1. CO2 CO2 CO2 CO2 . , , . , . 1990 25 CO2 , R&D CSR , , , , . , R&D.