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Abstract
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The effects of various concentrations of iron, zinc, and manganese on Arthrospira platensis MGH-1 growth and the capability of this cyanobacterium to accumulate these micronutrients were investigated. Maximum growth parameters were exhibited by A. platensis MGH-1 at 0.1 g L−1 iron, 2.0 mg L−1 zinc, and 6.0 mg L−1 manganese. The maximum bioaccumulation value was observed in 0.3 g L−1 iron, 8.0 mg L−1 zinc, and 40 mg L−1 manganese. The selection of the appropriate concentration for each micronutrient to produce A. platensis MGH-1 fortified with iron, zinc, and manganese was performed based on both the parameters of growth and accumulation of these metals. Then, the effects of selected concentrations for each micronutrient were investigated on photosynthetic pigments, protein and sugar contents, antioxidant enzyme activity, phenolic compound, and fatty acid content in A. platensis MGH-1. Maximum soluble sugar, phenolic compounds, and palmitoleic acid content were exhibited at 0.1 g L−1 iron. The highest amount of antioxidant enzyme activity and palmitic acid content was detected at 4.0 mg L−1 zinc-treated A. platensis MGH-1. The chlorophyll-a content increased significantly at 25 mg L−1 of manganese. Arthrospira platensis MGH-1 treated with the micronutrients contained high amounts of γ-linolenic acid (GLA, 18:3n-6) compared to the control. Overall, this study showed that 0.1 g L−1 iron and 25 mg L−1 manganese were appropriate concentrations of micronutrients to enrich A. platensis MGH-1 and it can be suggested for the development of functional foods. Also, A. platensis MGH-1 fortified with 0.1 g L−1 iron has more potential to be used in nutraceutical/ functional food since it is very rich in bioactive compounds.
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