Modeling and validating Pseudomonas aeruginosa kinetic parameters based on simultaneous effect of bed temperature and moisture content using lignocellulosic substrate in packed-bed bioreactor

The aim of this study was to propose kinetic parameters of a bacterial growth and its products formation as functions of environmental conditions. Hence, the effect of temperature and initial moisture content on bacterial growth and rhamnolipid biosurfactant production by Pseudomonas aeruginosa were investigated in the first step. A mixture of corn bran and corn germ was used as substrate in small glass packed-bed laboratory bioreactors. Results showed the highest rhamnolipid production rate was observed in stationary phase and the highest growth and rhamnolipid production were at 35 degrees C and initial bed moisture of 70%. Then, kinetic parameters of the bacteria were determined using the fitting of kinetic models to experimental results of cumulative CO2, rhamnolipid amount and metabolic water production. After that, the kinetic parameters M-CO2 m(RL), m(w), and Y(X/W )were considered with constant values while mu(m), X-m, Y(X/CO2 )and( )Y(RL/X )were presented as functions of environ- mental conditions, by modifying a model and using 3-dimensional curve fitting. Finally, in order to validate the obtained kinetic parameters and functions, transport phenomena in a packed-bed bioreactor were modeled in 2-dimensions. The model results were verified by the experimental results obtained from a 3-liter glass packed-bed bioreactor and the validation was satisfactory. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.