Proses Transesterifikasi Biji Minyak Jarak dengan Bantuan Enzim Lipase sebagai Penghasil Biodiesel

The investigation was carried out to prevent the scarce of fosil based fuel. In this investigation used seed of castor oil plan (Jathropha curcas L.) as natural row material to make castor oils and converted to biodiesel so that it's friendly to the biological environment. Castor oils produced by extraction process with soxhletation methods used n-hexane solvent. The result of extraction then converted to biodiesel by transesterification process at optimum temperature 40o C with methanol and catalyzed with lipase enzyme. Free fatty acid analysis and total fat analysis was done to the result product, and then biodiesel converted value as 88.67% gotten. Some characteristics analysis of biodiesel castor oils like density, viscosity, pouring point, flaming point, and caloric value according ASTM D6751. The result of investigation showed castor oils biodiesel can be used as diesel fuel

Biosorpsi Ni2+ oleh Nannochloropsis Salina pada Medium Terpapar Ca2+

Research on biosorption of Ni2+ by N. salina in Ca2+ exposed medium has been done. This study aimed to determine the growth and efficiency of N. salina towards Ni2+ in Conwy Medium with addition of Ca2+. Exposure of mixed ions of Ni2+ 5 ppm and Ca2+ with variation of concentrations 10, 30, 50 ppm was conducted at the beginning of the growth of N. salina. The growth of N. salina was observed every day by counting the number of N. salina population using a microscope and haemocytometer. The concentration of metal ions after the exposure was determined by atomic absorption spectrophotometer. The growth of N. salina in medium with exposed metal ions is lower than the control. The maximum sorption efficiency of Ni2+ as a single ion is 55.2%. After exposure of mixed ions of Ni2+ and Ca2+ with variation of concentrations 10, 30, 50 ppm, the sorption efficiency of Ni2+ in sequents are 17.6%; 17.8%; and 19.6%; while the maximum sorption efficiency of N. salina towards Ca2+ are 5.1%; 7.1%; and 4.0% respectively.DOI :http://dx.doi.org/10.15408/jkv.v0i0.315