Synthesis of fatty acid methyl ester from the transesterification of high- and low-acid-content crude palm oil (Elaeis guineensis) and karanj oil (Pongamia pinnata) over a calcium–lanthanum–aluminum mixed-oxides catalyst Y. Syamsuddin a,b , M.N. Murat a , B.H. Hameed a,⇑ a School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia b Chemical Engineering Department, Engineering Faculty, Syiah Kuala University, Banda Aceh 23111, Indonesia highlights  Transesterification of vegetable oil with different acid contents into FAME.  Best conditions from the reaction of vegetable oils with different acid contents.  The synthesized catalyst was feasible for high- and low-acid-content oil.  The properties of both products confirmed the standard requirements. article info Article history: Received 15 February 2016 Received in revised form 15 April 2016 Accepted 16 April 2016 Available online 19 April 2016 Keywords: Calcium–lanthanum–aluminum catalyst Crude palm oil Karanj oil Fatty acid methyl ester Transesterification abstract The synthesis of fatty acid methyl ester (FAME) from the high- and low-acid-content feedstock of crude palm oil (CPO) and karanj oil (KO) was conducted over CaO–La 2 O 3 –Al 2 O 3 mixed-oxide catalyst. Various reaction parameters were investigated using a batch reactor to identify the best reaction condition that results in the highest FAME yield for each type of oil. The transesterification of CPO resulted in a 97.81% FAME yield with the process conditions of 170 °C reaction temperature, 15:1 DMC-to-CPO molar ratio, 180 min reaction time, and 10 wt.% catalyst loading. The transesterification of KO resulted in a 96.77% FAME yield with the conditions of 150 °C reaction temperature, 9:1 DMC-to-KO molar ratio, 180 min reaction time, and 5 wt.% catalyst loading. The properties of both products met the ASTM D6751 and EN 14214 standard requirements. The above results showed that the CaO–La 2 O 3 –Al 2 O 3 mixed-oxide catalyst was suitable for high- and low-acid-content vegetable oil. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction Currently, the need to develop renewable alternative fuels has been increasing because of the depletion of fossil fuel sources, aspi- rations of energy savings, and emission reduction of pollutants and CO 2 into the environment. Regarding alternative fuels, biodiesel is a promising type of fuel because of its renewability, biodegradabil- ity, and environmental friendliness. Biodiesel, which is also known as fatty acid methyl ester (FAME), is a mixture of methyl esters resulting from the transesterification reaction of edible or non- edible vegetable oil and animal fats with aliphatic alcohols with the aid of an acid or base catalyst; this type of fuel also conform to the ASTM D6751 specifications for use in diesel engines (Kurle et al., 2013). Transesterification can be conducted homogeneously or hetero- geneously. A heterogeneous catalytic process is more advanta- geous than a homogeneous one. A heterogeneous catalyst has higher activity, easier to separate and reuse, and release less pollu- tion to the environment than a homogeneous catalyst; therefore, the former reduces the overall production costs (Birla et al., 2012; Chen et al., 2013; Hu et al., 2012). Transesterification is usu- ally performed by reacting vegetable oil with methanol over a solid catalyst that produces FAME and glycerol. Many types of oil, including palm oil (Acevedo et al., 2015; Chen et al., 2014a; Witoon et al., 2014), soybean oil (Lu et al., 2015), sunflower oil (Kostic ´ et al., 2016), jatropha oil (Chen et al., 2014b; Wang et al., 2015), karanj oil (KO) (Prabhavathi Devi et al., 2014), and waste http://dx.doi.org/10.1016/j.biortech.2016.04.083 0960-8524/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: chbassim@usm.my (B.H. Hameed). Bioresource Technology 214 (2016) 248–252 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech