(619aa) Kinetics Modeling of Fed-Batch Lipid Accumulation of Activated Sludge

Recent studies have demonstrated the capability of activated sludge (AS) microbial consortia to accumulate lipid droplets under fed-batch cultivation on acetic acid as carbon source. The experiments were conducted in laboratory-scale bioreactors. The prediction of system performance at a large-scale implementation of the technology requires the mathematical modeling of the laboratory-scale bioprocess, so kinetic models must be fitted to the experimental data. This study models the kinetics of the AS microbial culture during the fed-batch cultivation.

Monod-type kinetic models were regressed to the experimental data using various numerical methods implemented in MATLAB. Initial data-fitting via unconstrained nonlinear optimization of least-square-error suffered from instability of solution and long computation time. Then the Markov Chain Monte Carlo (MCMC) method was implemented resulting to improved regression. That is, the model parametric constants converged while minimizing the least-square-error at a faster rate. This work describes the various components of the problem-solving strategy that enabled the kinetics modeling.