REVIEW ARTICLE Overview of the challenges in the production of biodiesel M. Meira & C. M. Quintella & E. M. O. Ribeiro & H. R. G. Silva & A. K. Guimarães Received: 9 June 2014 /Revised: 26 August 2014 /Accepted: 28 August 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract This paper presents an overview of the main chal- lenges in the production of biodiesel. Whereas the cost of biodiesel is determined for about 85 % by the cost of the raw material and that the most employed feedstock are oils used also for nutrition, it seems obvious that it is necessary to search for nonedible feedstock with low cost for the produc- tion of biodiesel. The choice of feedstock is based on variables such as the oil yield, local availability, cost, and government support. Feedstocks with higher oil yields are more preferable in the biodiesel industry because they can reduce the produc- tion cost. In Brazil, approximately 80 % of the biodiesel produced is made from soybean despite of its low oil content (18–21 %). The leadership of soybeans as feedstock for bio- diesel production is explained by the increasing demand for more protein meal. Coconut and babassu with more oil yield respectively with 62 and 60 % of oil content are likely substi- tutes for soybean. Castor bean, despite of its high oil content (50 %) and advantages, such as low production cost and its resistance to hydric stress, has some difficulties to meet the ANP regulations, mainly due to its high viscosity. However, castor bean biodiesel-diesel blends of up to 40 % are within specifications. Yield per hectare is another factor that should be considered in the choice of raw material for the production of biodiesel. Among the various oilseeds, oil palm deserves to be highlighted as the most productive. Keywords Biodiesel . Production . Feedstock . Cost 1 Introduction Biodiesel is increasingly important in the world energy matrix, and the demand for biodiesel worldwide is expected to in- crease significantly in the near future. In 2011, Brazil pro- duced 2.6 million m 3 . It was surpassed by the USA which produced 3.7 million m 3 , Germany which produced at 2.8 million m 3 , and Argentina which produced 2.7 million m 3 of biodiesel [1]. Biodiesel has several advantages when compared to diesel, such as it is biodegradable, with superior lubricity, renewable, nontoxic, has little or no sulfur content, ecologically friendly, and emission of CO 2 is greatly reduced, with appreciable reduction of some emitted pollutants, and nonhazardous to handle because its flash point is above 110 °C [2]. The main disadvantages of biodiesel are its higher viscosity, lower en- ergy content, higher nitrogen oxide (NO x ) emissions, lower engine speed and power, injector coking, engine compatibil- ity, high cost, and higher engine wear [3]. The advantages of biodiesel far outweigh their disadvantages, and for this reason, even if the cost of biodiesel is still greater than diesel, many governments sustain this production. The biodiesel called of first generation is characterized by being derived from feedstock with concurrent use in foods, such as soybean, corn, sunflower, and peanut. Competition with food makes edible oil not an ideal feedstock for biodiesel production due to the inevitable increase in food prices. More than 95 % of feedstocks used for biodiesel production come from edible oils [4]. As the world faces food shortage and rising prices of fuel, scientists worldwide are striving to de- velop raw materials for biofuels that do not divert food crops into energy. In this regard, several feedstocks have been investigated for the production of biodiesel [5–12]. Nonedible oil crops have advantages of being grown in wastelands that are not suitable for food crops, has low cost of cultivation, and can still sustain reasonably high yield without intensive care. M. Meira (*) Instituto de Educação, Ciência e Tecnologia da Bahia, Campus Simões Filho, Simões Filho, Bahia, Brazil e-mail: marilenameira@gmail.com C. M. Quintella : E. M. O. Ribeiro : H. R. G. Silva : A. K. Guimarães Instituto de Química, Universidade Federal da Bahia, Salvador, Bahia, Brazil Biomass Conv. Bioref. DOI 10.1007/s13399-014-0146-2