Regresar

Increase of the content of lipids and polyunsaturated fatty acids of a strain of Tetraselmis tetrathele through mutation-selection

Abstract:

The microalga Tetraselmis tetrathele was exposed to the mutagen ethyl methane sulfonate (EMS) in order to evaluate the mutation-selection as a strategy of genetic improvement. The possible mutants with increased accumulation of lipids and polyunsaturated fatty acids (PUFAs) were selected using Quizalofop (100μM), an inhibitor of lipid synthesis. Two mutant strains (15c and 30a) were selected and compared with the wild strain in its growth, contents of total lipids and PUFAs. Growth of the 15c and 30a mutants was similar (P>0.05) to that shown by the wild strain, with maximum cell density of 1,5×106; 1,3×106 y 1,5×106 cells/ml, respectively. The total lipids of mutants 15c and 30a were 85 and 62%, respectively, higher than the wild strain (8.8 ±0.32%). The contents of arachidonic acid for 15c and 30a strains were 92 and 90%, respectively, higher than the wild strain (4.0%). Eicosapentaenoic acid and docosahexaenoic acid values measured in the two mutants exceeded by more than 25% to those obtained in the wild strain. The results demonstrate the usefulness of the mutation-selection as a strategy to genetically improve T. tetrathele, being an advantageous technique when unknown mechanisms of regulation of the genes involved in the biosynthesis of the compound of interest or when site-directed mutagenesis and transgenic methodologies are poorly developed, as it is the case with the majority of microalgae.