Modulating phytohormone supplementation can efficiently increase biomass and lipid production in Spirulina (Arthrospira)

Spirulina is one of the most popular microalgae. Thus, it is essential to improve their biomass and macromolecule production. The adequacy of phytohormone supplementation was shown to be efficient in increasing biomass and lipid concentrations in other microalgae cultivation. Therefore, the present study aimed to investigate the influence of sampling frequency on the production of biomass and biomolecules of Spirulina sp. LEB 18 supplemented with trans-zeatin (tZ) and indole-3-acetic acid (IAA). The microalga was cultivated with tZ and IAA at concentrations 0.01, 0.1, 1, and 10 mg L-1, and the sampling frequency was tested daily and every 10 days. Treatments with a lower sampling frequency (every 10 days) and supplementation of 0.01 mg L-1 IAA enhanced the biomass accumulation by 50% (3.2 g L-1) and the lipid content by 58% (26.8%) than that of the experiment without phytohormone and daily sample removal (2.1 g L-1 and 16.9%, respectively). Therefore, we developed a new strategy to improve microalgal production by supplementing phytohormones. The investigation presents a cultivation system that is efficient and easy to implement in industries because it does not require alterations in the operational aspects of the cultivation.

Automated summary

The study successfully increased the biomass and lipid production of Spirulina by supplementing phytohormones tZ and IAA, and extending the sampling frequency. This new strategy is significant for microalgal production and easy to implement in industries.