Hormesis effect of the herbicide glyphosate on growth and lipid synthesis in the microalga Isochrysis galbana, an object of industrial cultivation

The use of plant growth regulators is a new strategy for the industrial cultivation of microalgae to enhance growth performance and bioproduct synthesis. In the presented study, the changes in growth rate, final abundance, photosynthetic apparatus efficiency, cell metabolic activity and specific lipid content were evaluated in the haptophyte alga Isochrysis galbana in response to exposure to the herbicide glyphosate (25–100 µg L⁻¹). The results showed that glyphosate at concentrations of 25–75 µg L⁻¹ stimulated the growth and final biomass of I. galbana. Stimulation of algal growth was associated with an increase in the metabolic activity of cells and the efficiency of their photosynthetic apparatus. An intensive accumulation of lipids was observed in I. galbana at a glyphosate concentration of 50–75 µg L⁻¹. Overall, the study demonstrates a potential strategy to utilise I. galbana to remove high concentrations of glyphosate from the medium while producing lipid-rich algal biomass.