Isolation and characterization of wax esters from Calanus finmarchicus

Abstract

Calanus finmarchicus is a vast resource that until recently have been exploited to a minimal degree only. In the last few years harvesting and processing methods have been developed. There is a large market and great interest in products derived from marine oils. Most of the products today are derived from organisms at a high trophic level, i.e. products derived from cod liver oil. One disadvantage with these products is high levels of fat-soluble pollutants that require extensive purification before the products can be released to the market. As C. finmarchicus exists on the first trophic levels it is not polluted and is therefore very interesting as a substitution for cod liver oil, which is the main source for ω-3 fatty acids. In addition to this studies have shown that the oil extracted from the animal, Calanus oil, have beneficial properties and can reduce the risk for coronary heart disease, cancer and inflammation and this could be attributed to the contents of wax esters, high levels of a natural antioxidant, Astaxantine, and high levels of phytosterols. The aim of this thesis was to isolate and characterize the wax esters of the oil, and elucidate their structure.

The wax esters were first separated from the Calanus oil with silica SPE and then transesterified to FAME and FAL. The two structures types were separated into two fractions with APS SPE. The FAME were analyzed as their picolinyl esters in GC-MS for structure elucidation and the FAL as their nicotinate esters and TMS ethers. The fractions from various SPE columns were tested by use of TLC and/or GC-MS to confirm that they contained the actual compounds.

The FAME found were in a range of 14 to 22 carbon chain length, and there were saturated, monounsaturated and polyunsaturated FAME present. The PUFA were 18:4 (n-5, 7, 9, 11) and 22:5 (n-5, 7, 9, 11, 13). The FAL identified ranged from 16 to 22 carbon atoms in chain length, and were mostly monounsaturated, but one saturated compound was found.

The next step would now be to analyze the wax esters in LC-MS to find the complete structure using the pieces of structure found in the FAME and FAL, as there are limited numbers of combinations of the FAME and FAL in a wax ester.