<![CDATA[Cadangan minyak bumi semakin menipis, sehingga dicari bahan bakar alternatif, salah satunya adalah biodiesel. Minyak nabati terutama minyak sawit merupakan bahan baku edible sedangkan lemak sapi merupakan bahan baku non-edible dengan biaya rendah dan memiliki ketersediaan tinggi pada produksi sapi. Pemanfaatan lemak sapi yang belum maksimal dapat digunakan bersama minyak sawit untuk menghasilkan biodiesel. Lemak sapi dicairkan supaya menjadi minyak sapi. Bahan baku minyak sapi dan minyak sawit dicampur dengan perban-dingan 3:1. Campuran minyak ditransesterifikasi dengan metanol dengan perbandingan molar (1:6) dan katalis NaOH. Proses dilakukan selama 90 menit pada suhu ñ65ðC. Hasil proses transesterifikasi adalah metil ester dan gliserol. Metil ester pada lapisan atas dipisahkan dari gliserol kemudian dilakukan pencucian. Metil ester atau biodiesel selanjutnya diuji angka asam, viskositas, densitas, dan analisis menggunakan GC-MS. Yield biodiesel yang dihasilkan dari campuran minyak sapi dan minyak sawit adalah 76%, angka asam 0,67124 mg-KOH/g, densitas 857,76 kg/cmó, dan viskositas 3,0074 mm2/s. Kesemua parameter tersebut sesuai dengan standart mutu SNI biodiesel. Kandungan metil ester dari minyak sawit dan lemak sapi adalah metiloleat dan metil palmitat.àThe availability of the fossil fuel is decreasing; hence the finding of an alternative fuels is very important. One of those alternative fuels is biodiesel. Vegetable oil, especially palm oil is the edible raw material, while the beef tallow is the non-edible raw material with low cost production and the availability is huge in the cattle production. The beef tallow mixed with palm oil can be used as raw material for producing biodiesel. Firstly, the beef tallow was melted into beef oil. The raw materials of beef tallow and palm oil were mixed with the composition ratio of 3:1. The resulted mixed-oil was transesterificated by adding methanol with molar ratio of 1:6 and NaOH as catalyst. The transesterification process was carried for 90 minutes at ñ65ðC. Transesterification process produces methyl ester and glycerol. The produced methyl ester on the upper layer was separated from the glycerol and then washed. The produced methyl ester was tested to determine the acid number, viscosity, and density. Analysis of the methyl ester components using GC-MS was also conducted. The experimental results show the yield of produced biodiesel from mixed-oil of beef tallow and palm oil (3:1) was 75.93%. The tested acid number, density, and viscosity were 0.67124 mg-KOH/g, 85.76 kg/cmó, and 3.0074 mm2/s, respectively. Data of the tested methyl ester properties are in accordance with the quality of standard ISO for methyl ester. The content of the produced methyl ester from the mixed-oil of beef tallow and palm oil are metiloleat and methyl palmitate.]]>
