Enhanced arachidonic acid production from Mortierella alpina combining atmospheric and room temperature plasma (ARTP) and diethyl sulfate treatments

•Novel mutagenesis technique with ARTP was performed for this study.•An integrated and targeted method was established to select mutant strains.•The relative content of ARA increased to 45.64%.•The maximum of ARA yield reached 6.82 g/L.

To obtain mutant strains with higher arachidonic acid (ARA) yields, the oleaginous fungus Mortierella alpina was mutated using atmospheric and room temperature plasma (ARTP) coupled with diethyl sulfate (DES). A visual compound filter operation was used in which a screening medium was supplemented with cerulenin, an inhibitor of fatty acid synthase (FAS), and triphenyltetrazolium chloride (TTC). The mutant strain D20 with an ARA production of 5.09 g/L, a 40.61% increase over the original strain (3.62 g/L), was isolated. The relative ARA content increased from 38.99% to 45.64% of total fatty acids. After optimizing fermentation conditions, the maximum ARA yield (6.82 g/L) for strain D20 was obtained in shake flasks. This work provides an appropriate strategy for obtaining high ARA-yield strains by conventional random mutation methods with an efficient screening assay.