A Kinetic Model for Algal Phosphate Uptake and Growth.

A structured model introduced by considering algal mass to be composed of two components which were an intracellular phosphate and a structural substance, was proposed for algal phosphate uptake and growth dynamics. Further, the kinetics for phosphate uptake and growth of Microcystis aeruginosa were investigated at steady state or transient state, using continuous and batch culture experiments.Continuous culture experiments indicated that specific growth rate, μ was expressed as a hyperbolic function of intracellular phosphorus content, fP. While, specific rate of phosphate uptake, σ was inversely as fP. The fP values ranged from a maximum of about 5.0% to a minimum of about 0.15% phosphate per cell dry weight.At balanced growth, σ was related to μ and fP in the form of σ=fP·μ which was derived from the model presented here. So, parabolic relationship was found between σ and μ, because fP increased with increasing μ.The kinetic equation of transient phosphate uptake was given by dfp/dt=σ-μ·fP. This kinetic model was able to simulate overplus phenomena that when M. aeruginosa grown in a phosphate deficient continuous culture was suddenly brought into contact with a phosphate rich medium, phosphate was accumulated into the cell above the intracellular content required to sustain maximum growth rate.