Selection of a DGLA-producing mutant of the microalga Parietochloris incisa: I. Identification of mutation site and expression of VLC-PUFA biosynthesis genes Academic Article uri icon

abstract

  • Chemical mutagenesis of the phototrophic green microalga Parietochloris incisa, producing high amounts of arachidonic acid (ARA), resulted in selection of a mutant deficient in ARA and rich in dihomo-γ-linolenic acid (DGLA) and thus∆ 5 desaturase defective. The mutagenesis produced a nonsense mutation in the∆ 5 desaturase gene, resulting in alteration of the 62nd codon TGG into a stop codon. Thus, the polypeptide encoded by the mutant∆ 5 desaturase gene is severely truncated and biochemically inactive, as was confirmed by heterologous expression in Saccharomyces cerevisiae. The mutation did not affect the oleogenic nature of the strain, and the total fatty acid content in the mutant biomass reached 39%, in comparison to 34% in the wild type, after 14 days of nitrogen starvation; biomass yields amounted to 5.1 and 3.6 g/l, respectively. While in the wild type, DGLA …

publication date

  • January 1, 2011