Enzymatic purification of polyunsaturated fatty acids

Area of Science:

• Biochemistry
• Organic Chemistry
• Pharmaceutical Science

Background:

• Polyunsaturated fatty acids (PUFAs) possess significant physiological roles and therapeutic potential.
• Existing industrial purification methods for many PUFAs, including docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), and arachidonic acid (AA), are not well-established.
• PUFAs are susceptible to degradation by heat and oxidation, complicating purification.

Purpose of the Study:

• To develop efficient and industrially viable purification processes for valuable PUFAs.
• To overcome the instability challenges associated with PUFA purification.
• To enable the pharmaceutical utilization of various PUFAs.

Main Methods:

• Selective enzymatic esterification of free fatty acids (FFAs) from PUFA-rich oils with lauryl alcohol (LauOH) using a lipase with weak specificity.
• Selective enzymatic alcoholysis of PUFA ethyl esters from PUFA-rich oils with LauOH.
• Separation of purified PUFAs or PUFA ethyl esters from reaction mixtures using conventional distillation, leveraging differences in molecular weight.

Main Results:

• Selective esterification achieved high purity for DHA (91 wt%), GLA (98 wt%), and n-6 PUFAs rich in AA (96 wt%).
• Selective alcoholysis successfully increased the purity of ethyl docosahexaenoate to 90 wt%.
• Enzymatic approaches proved effective in enriching target PUFAs while mitigating degradation.

Conclusions:

• Enzymatic esterification and alcoholysis offer efficient and scalable methods for purifying valuable PUFAs.
• These purification strategies address the instability of PUFAs and facilitate their isolation.
• The developed methods support the potential pharmaceutical development of DHA, GLA, and AA.