Hindawi Publishing Corporation International Journal of Chemical Engineering Volume 2013, Article ID 425604, 7 pages http://dx.doi.org/10.1155/2013/425604 Research Article Biomass Production and Ester Synthesis by In Situ Transesterification/Esterification Using the Microalga Spirulina platensis Tatiana Rodrigues da Silva Baumgartner, 1 Jorge Augusto Mendes Burak, 1 Dirceu Baumgartner, 2 Gisella Maria Zanin, 1 and Pedro Augusto Arroyo 1 1 Departamento de Engenharia Qu´ ımica, Universidade Estadual de Maring´ a (DEQ/UEM), Avenida Colombo 5790, Bloco D90, 87020-900 Maring´ a, PR, Brazil 2 Departamento de Engenharias e Ciˆ encias Exatas, Universidade Estadual do Oeste do Paran´ a (UNIOESTE), Rua da Faculdade 645, Gerpel, 85903-000 Toledo, PR, Brazil Correspondence should be addressed to Tatiana Rodrigues da Silva Baumgartner; tati.rb@hotmail.com Received 30 April 2013; Revised 2 July 2013; Accepted 12 July 2013 Academic Editor: Said Galai Copyright © 2013 Tatiana Rodrigues da Silva Baumgartner et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. he increasing energy demand and reduction in the availability of nonrenewable energy sources, allied with an increase in public environmental awareness, have stimulated a search for alternative energy sources. he present study was aimed at producing biomass from the microalga Spirulina platensis and at assessing in situ synthesis of alkyl esters via acid transester- iication/esteriication of biomass to produce biodiesel. Two alcohols (ethanol and methanol) and two cosolvents (hexane and chloroform) were tested, at diferent temperatures (30, 45, 60, 75, and 90 ∘ C) and reaction times (10, 20, 30, 60, and 120 min). he factorial analysis of variance detected an interaction between the factors ( < 0.05): temperature, reaction time, alcohol, and cosolvent. he best yields were obtained with the combination ethanol and chloroform at 60 ∘ C, ater 30 min of reaction, and with hexane at 45 ∘ C, ater 10 min of reaction. In situ transesteriication/esteriication of alga biomass to form esters for biodiesel production adds unconventional dynamics to the use of this feedstock. 1. Introduction he global concern about future availability of energy comes from national security, economic stability, and environmental sustainability issues [1, 2]. In this context, the demand for petroleum derivatives has increased, but the current concern about reduction in pollution and the energy crisis has stimulated the global biofuel market. he global economy keeps increasing and so does the need for clean, renewable energy sources [3]. In the sector of automotive fuels, the inclusion of renew- able fuels, such as biodiesel, has several advantages, such as a reduction in pollution caused by exhaust emissions. Fur- thermore, biodiesel is an alternative to petroleum and con- tributes to regional development and social security, mainly in developing countries [4, 5]. A wide variety of feedstocks are currently used for bio- diesel production, and microalgae have been considered a potentially useful and promising biodiesel source, because they are photosynthesizing organisms very eicient in the process of converting light into chemical energy [6–8]. In addition, microalgae stand out for presenting high produc- tivity, exceeding that of any commercially produced plant in the world [9–11]. Microalgae have a life cycle of a few days and they may use CO 2 from polluting companies as an input for photosynthesis, which helps decrease the emission of green- house gases; hence, microalgae may contribute signiicantly to the global energy matrix [9–11]. Microalgae contain lipids and fatty acids as membrane components, storage products, metabolites, and energy sou- rces. Each microalga species produces diferent proportions of lipids, carbohydrates, and protein. Algal lipids are typically