Abscisic acid improves the safflower seed oil content for biodiesel production via CtDof2 gene regulation

Biodiesel , an alternative to fossil fuel , is an important sustainable energy source and has thus received considerable attention under global energy crisis scenarios. Safflower seed oil is a good substrate for biodiesel production, however, the poor oxidative stability of safflower seed oil is one of the factors limiting the quality of biodiesel. This study aimed to optimize the safflower seed oil-based biodiesel production process and attempted to regulate the expression of the CtDof2 gene through abscisic acid to affect the safflower seed oil content, thereby improving biodiesel yield. This research optimized the preparation conditions: catalyst concentration 0.56%, molar ratio of oil to alcohol 1:6.4 and temperature 105 ℃ using response surface methodology , and the highest yield of biodiesel was 95.7 ± 0.2%. To test hypothesis that the application of abscisic acid alters safflower seed oil content via CtDof gene regulation, we expressed CtDof2 in yeast, which increased yeast oleic acid content by 27.3% and decreased stearic acid content by 20.6%. The increase in monounsaturated fatty acids predicts the improvement of biodiesel quality. Meanwhile, abscisic acid altered the fatty acid composition of safflower seed oil by regulating CtDof2 , leading to an increase in the antioxidant capacity of biodiesel. This study provides new ideas for the improvement of biodiesel feedstock and the improvement of biodiesel quality in the future. • CtDof2 gene can increase oleic acid content, thus improving the antioxidant performance of biodiesel in the study. • The abscisic acid up-regulate the expression of CtDof2 gene, so improve the antioxidant performance of biodiesel. • The process conditions for thepreparation of SSO-based biodiesel were optimized by RSM.