Artigo:

The use of microalgal biomass in the production of biofuels and bioproducts are an area of research which has received attention in recent years. The aim of this study was to screen the biochemical composition of five different microalgal biomass: Chlorella vulgaris, Spirulina platensis, Scenedesmus spp., Porphyridium cruentum and Phaeodactylum tricornutum for biodiesel and bioproducts application. Green microalgae (C. vulgaris and Scenedesmus spp.) showed high protein contents 56.1% and 49.0% respectively. Red microalgae P. cruentum presented high carbohydrate content of about 34.5%. The lipid content in microalgae biomasses ranged from 7.4 to 12.5%. C. vulgaris and Scenedesmus spp. showed the highest lipid content 12.5% and 12.1 %, respectively. S. platensis and P. tricornutum showed oil rich in saturated fatty acids (SFA), specially palmitic acid (C:16:0). Monounsaturated fatty acid (MUFA) was observed at high content in P. cruentum (40.7%). Scenedesmus spp. and C. vulgaris presented high polyunsaturated fatty acids (PUFA’s), which proportions of 41.6% and 41.2%, respectively. P. cruentum and P. tricornutum are also source of PUFA’s, mainly eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6). 1. INTRODUCTION Microalgae use photosynthesis to convert solar energy into chemical energy. It is stored in the form of oils, carbohydrates, proteins, etc. This energy can be converted to biofuels. In the context of climatic changes and of soaring prices for a barrel of petroleum, biofuels are now being presented as a renewable energy alternative. Presently, research is being done on microscopic algae, or microalgae, which are particularly rich in oils and whose yield per hectare is considerably higher than that of soybean or rapeseed (Richmond, 2004; Demirbas and Fatih Demirbas, 2010). Oil productivity, that is the mass of oil produced per unit volume of the microalgal broth per day, depends on the algal growth rate and the oil content of the biomass. Microalgae Área temática: Processos Biotecnológicos 1with high oil productivities are desired for producing biodiesel. Production of biodiesel from microalgal oil can be done by transesterification reaction, that produces esters of fatty acids that are biodiesel, and glycerol (Chisti, 2007). It is well understood that the fatty acid composition (carbon chain length and degree of unsaturation) of microalgal has a major effect on biodiesel properties. The most important characteristics affected by the level of unsaturation are oxidative stability, ignition quality and cold flow properties (Bucy et al., 2012). The addition of microalgal biomass to food products is an interesting tool for providing nutritional supplementation with biologically active compounds (e.g. antioxidants, PUFA’s), besides the high protein and carbohydrate contents. Accordingly, the selection of microalgae species with balanced nutritional profiles is fundamental for successful novel foods development. A detailed physicochemical characterization of the microalgae is an essential stage that will allow determining which algae are best suited for different applications and purposes (Batista et al., 2013). Microalgae are present in all existing earth ecosystems, representing a big variety of species living in a wide range of environmental conditions. It is estimated that more than 50,000 species exist, but only a limited number, of around 3,000 have been studied and analyzed (Mata et al., 2010). For this purpose the screening/investigation of the biochemical composition and the fatty acids profile from microalgae strains is necessary. 2. MICROALGAL BIOMASS The microalgae used in this work were cultivated in Laboratory of Food Biotechnology/Center of Agricultural Science and in Laboratory of Algae Cultivation/ Aquaculture Department, both departments located at Federal University of Santa Catarina. The growth characteristics for mass culture are shown in Table 1. Table 1 – The main characteristics of microalgal cultures Microalgae Classification Habitat Culture Medium Photobioreactor