Leila Zarandi Miandooab, Mohammad B. Bagherieh-Najjar, Mohammad A. Hejazi, Nader Chaparzadeh,
Volume 4, Issue 12 (VOL. 4, No. 12, 2015 2015)
Abstract
Dunaliella salina, a unicellular green microalga with ability of large quantity β-carotene accumulation, was used as a proper model for analysis of expression of the pds and lyc genes, involved in β-carotene biosynthesis pathway, under different light intensities and salinity concentrations. For this purpose, an experiment with two factors, light intensities (200 and 1000 µmol m-2s-1) and salinity (2 and 4 M NaCl) were performed in completely randomized factorial design. During 4 days, the steady-state levels of transcripts encoding phytoen desaturase increased substantially in 200-4 and 1000-2 treatments, while lycopene beta cyclase transcripts increased in 200-2, 1000-2 and 1000-4 treatments. As an enhancement effect of increased expression of both genes, the β-carotene reached to its maximum amount in 1000-2 treatment. These results indicated that light intensity induced the expression of the above indicated β-carotene biosynthesis pathway genes. The accumulation of β-carotene could be considered as a protection mechanism of the algae against oxidative stress originated from primary light stress.
Farzaneh Fekrat, Maryam Shahbazi, Mohammad Amin Hejazi, Behnam Nami,
Volume 11, Issue 48 (vol. 11, no. 48 2022)
Abstract
Spirulina microalgae are a rich source of protein and valuable biological compounds. One of the most important Spirulina microalgae pigments is phycocyanin. Phycocyanin is widely used in industries as a natural blue pigment and it’s also an effective antioxidant. In order to improve phycocyanin production as well as Spirulina growth, by autotrophic cultivation considering that autotrophic cultivation depends mainly on the source of light with different wavelength distribution and intensity and also access of the Spirulina microalgae to nutrients ingredient in culture medium. Given that phycocyanin is a photosynthetic pigment, and a component of light-harvesting (antenna) complexes, the rate and efficiency of the photosynthetic activity is important in the production of phycocyanin. In this study, the molecular 16srRNA identification of spirulina strains was performed. The best strain (Arthrospira platensis NIES-39) in terms of biomass and phycocyanin production was selected from five spirulina strains. The effect of different super Light Emitting Diode (LED) emitting white, red and blue as a light source in terms of biomass and phycocyanin production in Arthrospira platensis NIES-39 were compared, and the results showed that white super LED had the best performance significantly in terms of biomass production (4.71 g/l) and the highest concentration of phycocyanin (0.316 mg/ml). But the purity of phycocyanin produced by blue super LED (1.04) was significantly higher than white super LED (0.77) and others. The results also showed that the use of combined wavelengths of white and red super LEDs in the growth stages of Arthrospira platensis NIES-39 compared to the use of only each ones increased the growth rate of algae and three-day shortening the growth period to achieve the maximum biomass (4.67 g/l). As a general result, it can be said that the use of super LED could increase the biomass, purity and amount of phycocyanin produced in the economic production of this microalgae.
