# Iron biofortification as a promising strategy to improve productivity and nutritional value of Arthrospira platensis (spirulina)

## TL;DR

This study shows that adding iron to spirulina improves its growth and nutritional value, but too much can cause harmful effects.

## Contribution

The study identifies optimal iron levels for enhancing spirulina's productivity and nutritional profile while minimizing oxidative stress.

## Key findings

- Moderate iron levels (32 mg L−1) increased biomass productivity and unsaturated fatty acids.
- Higher iron levels (64 mg L−1) significantly boosted phenolics like benzoic and gallic acids.
- Iron biofortification improved growth rate and protein content but also increased reactive oxygen species.

## Abstract

Arthrospira platensis (spirulina) is widely recognized as a nutrient-dense cyanobacterium. The present study is aimed at investigating the role of iron biofortification on the productivity and nutritional value of the biomass. The cyanobacterium was grown in the Zarrouk’s medium supplemented with certain iron concentrations (2, 8, 16, 32, and 64 mg L− 1). The biomass growth was assessed by measuring specific growth rate and yield and then analyzed for iron uptake, protein, carbohydrates, fatty acids, phycobiliproteins, and phenolics by different assays using UV/Vis spectroscopy and inductively coupled plasma optical emission spectrometry. Increasing iron levels in the media resulted in higher growth rate, biomass density, protein, carbohydrates, and reactive oxygen species. We only observed significant changes in fatty acids, phycobiliproteins, and phenolics at iron levels > 16 mg L− 1. The highest unsaturated fatty acids and phycocyanin were observed at the moderate iron levels (~ 32 mg L− 1); while higher values increased phenolics, particularly benzoic and gallic acids (~ 2.5- to 7-fold). The moderate iron level is critical to increase biomass productivity, unsaturated fatty acids, and phycobiliproteins, to control anti-nutritional phenolics, and to minimize iron-induced oxidative stress.

The online version contains supplementary material available at 10.1038/s41598-026-40520-8.