On the modelling and surface response analysis of a non-conventional wall-cooled solid/gas bioreactor with application in esterification

Abstract

Solid/gas biocatalysis is, nowadays, an attractive discipline in biotechnology for applying synthesis reactions. The design of the solid/gas bioreactor is, nevertheless, the main engineering challenge for its application at full scale. Although modeling is the most reliable engineering tool to design a reaction technology and guide the experimental work, as far as the authors know, there is not, today, a mathematical model for the solid/gas bioreactor. To this end, this work is aimed at developing a pseudo-continuous model for a wall-cooled packed-bed reactor for solid/gas biocatalysis. Esterification of propionic acid and isobutyl alcohol on supported lipases extracted from Candida antarctica is implemented as the case study because of the importance of isobutyl propionate in the commodities market. The proposal and construction of the mathematical model are based on reactor engineering principles. Thus, the pseudo-continuous model is applied for carrying out parametric sensitivity and surface response analyses. The former contributes to understanding the complex microscopic interaction between thermodynamics, kinetics, and transport phenomena at the studied operating conditions and selected geometrical settings; while the latter allows the identification of the operational window where the biocatalyst meets its optimal macroscopic performance without having the well-known computational cost due to the time required to solve pseudo-continuous models accounting for the bioreactor heterogeneity and fluid dynamics. The pseudo-continuous model constitutes a valuable tool for future studies focused on either providing a deeper understanding of the solid/gas biocatalytic esterification or carrying out the conceptual design and operation of the solid/gas bioreactor.