The potential use of immobilized lipases in the synthesis of omega-3
monoacylglycerols enriched in stearidonic acid
Abstract
This work presents an original approach to develop an integrated process
to improve the nutritional characteristics of natural oils, starting
with the extraction from the raw material by environmentally friendly
methods and following with the production of novel acylglycerols using
immobilized lipases. Specifically, 2-monoacylglycerols (2-MAGs) enriched
in the omega-3 stearidonic acid (SDA) were synthesized by selective
ethanolysis of extracted Echium plantagineum oil using the lipase from
Thermomyces lanuginosus (TLL). Different reaction conditions were
investigated to minimize the undesirable acyl migration and to ensure
the purity of final products. The biocatalyst produced in our laboratory
by the immobilization of TLL on a hydrophobic support reached the
maximum theoretical amount of 2-MAG in only 2 h at mild reaction
conditions, achieving a product enriched in omega 3 SDA (up to 25%).
Moreover, the produced biocatalyst exhibited higher stability than
commercial lipases. The average activity after 5 cycles was 71%,
allowing several reutilization cycles and developing a feasible
enzymatic process. Finally, 2-MAGs was used as starting material to
synthesize structured triacyclglycerols (STAGs) in solvent-free systems.
The use of molecular sieves in combination with the immobilized lipase
from Rhizomucor miehei (RML) showed to be an extraordinarily fast
strategy to produce pure STAGs (100% in 1h), 4 times higher than the
activity showed by the commercial derivative. Thus, the enzymatic
processes developed in this study open a range of possibilities to
synthesize omega-3 acylglycerols with improved characteristics for
essential biological functions and nutritional advantages, proving the
usefulness of immobilized lipases to produce novel functional lipid.