Physicochemical and Thermal Characterization of the Spirulina platensis

Cyanobacterium Spirulina platensis is commercially produced as a nutrient source for food, animal feed and pharmaceutical industries, and is also explored in other applications in areas such as material sciences, materials engineering and for the production of biofuels and biochemicals. Due to the increasing interest in the use of this microalga, a complete characterization was intended, as to provide data to the insufficient literature. In this work, various techniques were used for thermal (thermogravimetric analysis (TGA)/derivative thermogravimetry (DTG), differential scanning calorimetry (DSC)), structural (scanning electron microscopy (SEM) and wide-angle X-ray diffraction (XRD)) and chemical (atomic absorption spectroscopy (AAS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), energy dispersive X-ray spectroscopy (EDX)) characterization of Spirulina cultivated in Brazil. Results have shown that in addition to the high quantity of protein (over 50%), Brazilian Spirulina is a source for carbohydrates (33%) and also has good thermal stability up to 200 °C. The pigment protein Phycocyanin could be identified by FTIR and ultraviolet-visible (UV-vis) spectroscopy. Results show favorable properties of Spirulina as a source for new materials and biomass.