Evaluation of phytohormone facilitation in microalgal biomass production using mathematical modeling

How to improve the growth efficiency of microalgae is the bottleneck of microalgae large-scale application. The addition of trace substances can promote the growth of microalgae, but there is no suitable model that can be used to predict the effects of trace substance concentrations on the growth of microalgae. In the present study, a mathematical model based on hormesis is proposed to describe the effects produced by trace substances on the biomass of microalgae and applied to assess the dose-response of four phytohormones on Scenedesmus sp. LX1 with a high coefficient of determination (R² ≥ 0.90). Several new mathematical parameters, such as starting effective dose (SD), inflection point dose (PD), concentration for 0 % of maximal effect, end effective dose (ED), maximum stimulatory effect (MSE), and maximum inhibitory effect (MIE), were extracted and useful to help researchers in applying trace substances to assist in the production of microalgal biomass for data reference and prediction. In concrete terms, the above model parameters can be well applied to screen the trace substances, dominant algal species and determine the concentration range. This study provides valuable insights into the potential of using phytohormones to enhance the biomass production of microalgae and offers a new approach to optimizing the culture of microalgae.