IIT Bombay 5th International Conference on Advances in Energy Research Velentina Das1, Anuchaya Devi2,Vijay Kumar Das3, Dhanapati Deka4* 1,2,4Biomass Conversion Laboratory, Department of Energy,Tezpur University, Napaam-784028, Assam, India 3Department of Chemical Sciences, Tezpur University-784028, Assam, India TEZPUR UNIVERSITY MICROALGAE CHLORELLA: A POTENTIAL FEEDSTOCK FOR BIODIESEL PRODUCTION - A REVIEW Microalgae are unicellular autotrophic/heterotrophic photosynthetically efficient organisms that uses light energy and carbon dioxide (CO2). Biofuel production from Microalgae Chlorella species have long been identified as potentially good source because of their high oil content, fast growth, easy cultivation, short life span. Chlorella parasitca is found to have symbiotic association in the cells of Paramecium and Hydra. Chlorella vulgaris, Chlorella conductrix, Chlorella Gonglomerata and C. parasitca are the common Indian species. Chlorella is represented by only eight species. Out of all these species, Chlorella vulgaris is one of the prominent algae species for producing biofuel because of its fast growth and easy cultivation. The microalgal biodiesel have many advantages as it can reduce net carbon dioxide emission by 78% on a life-cycle basis as compared to traditional diesel fuel Microalgal biodiesel also contain little or no sulphur or aromatic compound but in conventional diesel, the sulphur lead to formation of sulphur oxide and sulphuric acid, while the aromatic compound also increase particulate matter and are considered carcinogens. Table 2. Oil content in different microalgae Table 3. Comparison between microalgal biodiesel and diesel fuel Table 1.Different Esters present in Chlorella vulgaris Microalgae Oil content (% dry weight) Botryococcus braunii 25-75 Chlorella sp. 28-32 Crypthecodinium cohnii 20 Cylindrotheca sp. 16-37 Dunaliella primolecta 23 Isochrysis sp. 25-33 Nannochloropsis sp. >20 Neochloris sp. 31-68 Monolanthus salina 35-54 Nitzchia sp. 45-47 Phaeodactylum tricornutum 20-30 Schizochytrium sp. 50-77 Tetraselmis sueica 15-23 PROPERTIES BIODIESEL FROM MICROALGAL OIL DIESEL FUEL DENSITY (kgl-1) 0.864 0.838 VISCOSITY (Pa S) 5.2x10-4(40OC) 1.9-4.1 x10-4(40OC) FLASH POINT (OC) 65-115 75 SOLIDIFYING POINT (OC) -12 -50-10 COLD FILTER PLUGGING POINT (OC) -11 -3.0(-6.7 max) ACID VALUE ( KOH g-1) 0.374 0.5(max) HEATING VALUE (MJ Kg-1) 41 40-45 HC RATIO 1.18 SOURCE : DEPARTMENT OF BIOLOGICAL SCIENCES AND BIOTECHNOLOGY,TSINGHUA UNIVERSITY,BEIJING,CHINA 2004 Sl.N Ester from Chlorella vulgaris Found (%) 1 Methyl octanoate(C8:0) 0.0544 2 Methyl decanoate(C10:0) 0.01156 3 Methyl dodecanoate(C12:0) 0.0506 4 Methyl myristate(C14:0) 0.26075 5 Methyl palmitate(C16:0) 23.2466 6 Methyl palmitoleate(C16:1) 0.19769 7 Methyl stearate(C18:0) 1.31459 8 Methyl oleate(C18:1n9c) 29.98263 9 Methyl linoleate(C18:2n6c) 3.38901 10 Methyl linolenate(C18:3n3) 5.05722 11 Methyl arachidate(C20:0) 0.16254 12 Methyl behenate(C22:0) 0.21336 13 Methylcis-13-decosenoate(C22:1n9) 0.05382 Extraction Lipid content Algae culture Transesterification Renewable Catalyst Table No 4. Chemical composition of algae expressed on a dry matter basis (%) Recovery of the biodiesel by repeated washing Strain Protien Carbohydrate Lipids Nucleic Acid Scenedesmus obliquus 50-56 10-17 12-14 3-6 Scenedesmus quadricauda 47 - 1.9 Scenedesmus dimorphus 8-18 21-52 16-40 Chlamydomonas rheinhardii 48 17 21 Chlorella vulgaris 51-58 12-17 14-22 4.5 Chlorella pyrenoidosa 57 26 2 Spirogyra sp. 6-20 33-64 11-21 Dunaliella bioculata 49 4 8 Dunaliella salina 32 6 Euglena gracilis 39-61 14-18 14-20 Prymnesium parvum 28-45 25-33 22-38 1.2 Tetraselmis maculata 52 15 3 Porphyridium cruentum 28-39 40-57 9-14 Spirulina platensis 46-63 8-14 4-9 2-5 Spirulina maxima 60-71 13-16 6-7 3-4.5 Synechoccus sp. 63 11 5 Anabaena cylindrica 43-56 25-30 4.7 Analysis Density Viscosity Solidifying point Flash point Acid value Chlorella seems to be the dominating species in this field. Chlorella is found interesting for the development of second generation biofuel and because of being immense diversification among the other microalgal species found in different habitats of North East India. It can grow in salt water, freshwater or even contaminated water, or in ponds, and even on land which are not suitable for food production. On top of those advantages, algae can grow even better when fed extra carbon dioxide (the main greenhouse gas) and organic material like sewage. If so, along with biofuel production it can deal up with cleaning up other problems. Construction of a Open raceway Photobioreactor. Synthesis of renewable heterogeneous catalysts from egg shells for biodiesel production. Velentina Das Thanks Tezpur University for the Institutional Fellowship. IIT Bombay ICAER 2015