The Study of Linoleic Acid and Nanoparticles Effects As Inducers on Astaxanthin Production and Astaxanthin Metabolic Pathway Genes (Crto and Crtr) in Haematococcus Lacustris

Background and aim: astaxanthin is an applicable metabolite with a broad usage in medicine, fishery, biofuel, food, aviculture, agriculture, and cosmetic industries. haematococcus lacustris recognized as a good source for astaxanthin (ax) production. in this study, the effect of linoleic acid (la), titanium dioxide (tio2), and silicon dioxide (sio2) nanoparticles as inducers were investigated on astaxanthin production and gene expression of haematococcus lacustris autotrophically.methods: haematococcus lacustris cells cultured in bbm medium autotrophically, in the day of 3 after culture la and nanoparticle treatments (tio2 and sio2) incubated to the microalgal cultures, then in 3 days (10, 14,17th) astaxanthin was extracted and measured, while in 12th rna was extracted, cdna synthesized and real-time pcr applied. randomized complete bloke design (rcbd), 3 and 2 replications, anova with spss software and duncan multiple range test were used also significant difference against the control was 0.05 (p<0.05).results: results show that the addition of 30µm linoleic acid and tio2nps (40 mg l-1) enhanced astaxanthin production by 3.4 and 1.5 times compared to the control respectively. 30µm la and sio2 nps (40 mg l-1) increased expression of crto and crtr as important genes in the astaxanthin pathway in order. furthermore, the results of the study for the first time showed that the la and tio2 concentrations increased astaxanthin, and upregulated crto gene expression more than crtr; between the expression of crto and production of astaxanthin was seen a direct relationship.conclusion: linoleic acid and tio2 nps can be used as two effective elicitors for astaxanthin production and gene expression in haematococcus lacustris respectively.