No abstract

No abstract

Utilization of Jatropha curcas seed cake is limited by the presence of phorbol esters (PE), which are the main toxic compound and heat stable. The objective of this research was to optimize the reaction conditions of the enzymatic PE degradation of the defatted Jatropha curcas seed cake (DJSC) using the acetone-dried lipase from the germinated Jatropha curcas seeds as a biocatalyst. Response Surface Methodology (RSM) using three-factors-three-levels Box-Behnken design was used to evaluate the effects of the reaction time, the ratio of buffer volume to DJSC, and the ratio of enzyme to DJSC on PE degradation. The results showed that the optimum conditions of PE degradation were 29.33 h, 51.11 : 6 (mL/g), and 30.10 : 5 (U/g cake) for the reaction time, the ratio of buffer volume to DJSC, and the ratio of enzyme to DJSC, respectively. The predicted degradation of PE was 98.96% and not significantly different with the validated data of PE degradation. PE content was 0.035 mg/g, in which it was lower than PE in non-toxic Jatropha seeds. The results indicated that enzymatic degradation of PE might be a promising method for degradation of PE.

Fatty acid methyl esters (FAME) are produced by transesterification. The problem in the product of transesterification is the presence of impurities such as mono-, di-, triglycerides, and free fatty acids. So that, the purification using solvent fractionation is needed to separate them from FAME. The objective of this research were to determine the effects of crude fatty acid methyl esters-to-acetone (CFAME/acetone) ratio on yield, purity, purification factor, and recovery of FAME after fractionation and to evaluate the impurities which were separated in each step of fractionation. FAME were produced from Jatropha curcas oil using Berchmans's and Tiwari's methods. The impurities were separated by solvent fractionation using acetone. CFAME/acetone ratios were 1, 2, 3, 4, and 5. Fractionation was done stepwise namely 21°C, 16°C, 12°C, and 5°C. The results showed that the conversion of FAME using Tiwari's method was 1.7-fold higher than Berchmans's method. Purification of FAME using solvent fractionation resulted that the best CFAME/acetone ratio was 1. Yield decreased 1.6-fold at CFAME/acetone ratio 4. Purity decreased 8.74% with an increase in CFAME/acetone ratio 1 to 5. Purification factor decreased 2-fold at CFAME/acetone 1 to 3. Recovery decreased 1.3-fold at CFAME/acetone ratio 1 to 4. The impurities which were separated from FAME were mono-, di-, triglycerides, and free fatty acids and the major component of impurities was triglycerides (>59%). The results indicated that solvent fractionation could be used as an alternative method for purifying FAME and further study to optimize this method was needed.