Study on biofiltration capacity and kinetics of nutrient uptake by Gracilaria cervicornis (Turner) J. Agardh (Rhodophyta, Gracilariaceae)

The absorption efficiency and kinetic parameters (V(max), K(s) and V(max) : K(s)) of the seaweed Gracilaria cervicornis for the nutrients NH(4)(+), NO(3)(-) and PO(4)(3-) were evaluated. Absorption efficiency was measured by monitoring nutrient concentrations for 5 h in culture media with initial concentrations of 5, 10, 20 and 30 mu M. Kinetic parameters were determined by using the Michaelis-Menten formula. Absorption efficiencies for this algae were greater in treatments with lower concentrations, as evidenced by a reduction of 85.3, 97.5 and 81.2% for NH(4)(+), NO(3)(-) and PO(4)(3-), respectively. Kinetic parameters show that G. cervicornis exhibits greater ability to take up high concentrations of NH(4)(+) (V(max) = 158.5 mu M g(dw)(-1) h(-1)) and low concentrations of PO(4)(3-) (K(s) = 5 mu M and V(max) : K(s) = 10.3). These results suggest that this algal species has good absorption capacity for the nutrients tested and may be a promising candidate as a bioremediator of eutrophized environments.