I need to perform enzymatic transesterification of fish oil for the production EPA-EE (EPA ethyl ester).
In case of enzymatic transesterification, is it needed to add KOH or H2SO4? Do wee need to carry out the base and acid catalyzed transesterification?
Is transesterification and ethanolysis the same process?
Need guidance on this because this a crucial part on my project.
Thanks in advance.
http://www.ncbi.nlm.nih.gov/m/pubmed/26370800/?i=2&from=transesterification%20of%20fish%20oil
Hi Kavitha,
Transestrification is replacing of original ester groups into desired esters. If you are converting fish oil that are triglycerides into a ethyl esters yes it is transesterifications, since ethanol is involved some times it called ethanolysis
The best way to convert transesterifcation would be base catalyzed transesterifcation. It is very facile reaction . You can first convert triglycerides into sodium or potassium salt using absolute ethanolic solutions of one of these salts followed by addition of ethanol containing 1% sulfuric acid to complete the reaction. The transeterification by this method is quantitative. I use regularly this method for converting fish oils into EE for estimation of EPA/DHA.Hope this helps you.
Thanks y=for your response Abdur Mirajkar. What about if we use sodium ethoxide in case the lipase does not work out in this process?
After the transesterification process, two layers will be formed. Which one is the EPA ethyl ester layer?
Sure, you can use if sodium ethaoxide is fresh and free from moisture.The reason I mentioned about ethanol and sodium hydroxide is because it is freshly prepared and has high reactivity. After esterfication is performed, add more water followed by organic solvent such as hexanes.The top layer would be a esters in hexanes due to high solubility. This way you can extract all esters into hexane layer. Wash hexane layer with water (DI) and separate water layer again (lower). If you are injecting to GC, dry the hexane layer with anhydrous sodium sulfate before injecting to GC.
If you don't want extract, your top layer would still be esters due to non miscibility . But you will lose some esters in aqueous due to presence of ethanol that solublizes the esters.Hope this explanation helps you further in your experiments.
Thanks, Abdur Mirajkar. I'm going to collect the oil which contains ethyl ester. I'm doing thin layer chromatography for free fatty acid (FFA) identification and quantification.
Please note that if you would like to go for enzymatic transesterification, you need not to use any acid or base catalyst. your enzyme only will work as catalyst. You need not to check FFA of your oil in case of enzymatic process.
Transesterification and ethanolysis mean the same process. If you are using methanol for your reaction, then it will be called as methanolysis.
Yes, you can run a TLC using HEX:Ether:AA (60:40:1) ratios of mobile phase on a silica gel plates. This way you can figure out MD,DG,FFA on a TLC plate.Alternatively, if you are looking for only FFA, you can directly titrate sample using AOAC method for FFA, is that something you are interested ?
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