Iron nutrition in bacteria presents a fundamental challenge due to its extremely low solubility in aerobic environments at moderate pH. For optimal growth, Pseudomonas bacteria necessitate about 10 e-6 to 10 e-7 M of bioavailable iron and therefore solve an iron supply problem for survival by synthesizing and exporting a low-molecular-weight compound called siderophore. The latter has a high iron binding capability from the bacterial cell, and then importing it once bound to iron. A system of nonlinear ordinary differential equations has been studied and a parameter identification study conducted on unknown parameters along with a sensitivity analysis to determine key factors that contribute most to the variation in model outputs (experimental observations). The model has been quantitatively validated against population size count and pyoverdine content measurements obtained from Pseudomonas fluorescens pf-10 strain, the model solution can be used as an indirect experimental tool for developing practical criteria in plant growth-promoting rhizobacteria (PGPR) selections which are known to provide effective rhizosphere colonization, together with accurate predictions of iron depletion in the system over time. 

 

Key words: P. fluorescens Pf-10, pyoverdine, Iron chelating, model calibration, sensitivity analysis.