Simulation on non-ideal behaviour of plug flow bioreactor based on the growth study of Lactobacillus species

ABSTRACT The physical properties of a biological system vary with time due to the growth of biomass, and thus the flowability of such a medium inside any bioreactor also changes with time. The present study aims to study the non-ideal behaviour of a plug flow bioreactor (PFBR) under non-reactive conditions for a biological system. Different physical parameters of this study have been incorporated from the batch growth study of Lactobacillus sp. The growth of bacteria culture was simulated using a PVA solution to conduct residence time distribution (RTD) experiments in pulse and step mode. Different parameters of the dispersion model were measured, and the non-zero variance indicated that dispersion always occurred along the path of reaction which led to turbulence and diffusion. The Peclet No was non-infinite; thus, PFBR always deviates from the ideal behaviour of the plug flow reactor. During the velocity distribution study, it had also been established that the Peclet number was decreased with the increase of Reynolds Number at a certain medium viscosity. Moreover, the non-ideality of PFBR further increased due to the change of physical properties of the medium. Here, a polynomial relation had been established between the Peclet number and medium viscosity. Therefore, the current study might be a value addition towards the designing of the plug flow bioreactor. GRAPHICAL ABSTRACT