As fish farm wastewaters have detectable levels of fish hormones, such as 17β-estradiol (E2), an understanding of the influence of fish steroids on algal (Scenedesmus quadricauda) and duckweed (Lemna minor) physiology is relevant to the potential use of fishery wastewaters for microalgae and plant biomass production. The study was conducted using three types of media: Bold Basal Medium (BBM), natural fishery wastewater (FWW), and reconstituted fishery wastewater (RFWW) with the nutrient composition adjusted to mimic FWW. During the experiment, the media were aerated and changes in the pH and conductivity of the water were closely monitored. E2 promoted the growth of S. quadricauda and L. minor, with significant accumulation of high-value biomolecules at very low steroid concentrations. However, clear differences in growth performance were observed in both test cultures, S. quadricauda and L. minor, grown in different media, and the most effective hormone concentrations were evidently different for the algae and the plant.
Keywords: Lemna minor; Scenedesmus quadricauda; aquaponics; biomolecule synthesis; fish wastewater; population growth; steroid 17β-estradiol.