Development, Validation and Comprehensive Sensitivity Analysis of a Fermentation Model Expediting the Process Design of a Biorefinery

The Sustainable Development Goals of the United Nations (UN-SDG) demand inter alia a transition towards sustainable and responsible economic production patterns [1]. A key approach in achieving these goals is the concept of a biorefinery, in which the processing of lignocellulosic biomass (LB) serves to provide multiple value-adding products [2]. A major drawback though still remains its economic profitability. Therefore, extensive research and development efforts are required to design, analyze and holistically optimize biorefinery concepts in order to enhance their economic feasibility [3]. For these purposes, tools from Process Systems Engineering (PSE) can be employed to give adequate responses to questions from unit level up to the plant-in-market level. The focus of this contribution lies on the production of xylitol by fermentation in a biorefinery. Xylitol can be a highly value-adding product due to its increasing demand in e.g. the health industry [4]. Therefore, a first-principles fermentation model is developed to describe mechanistically the yield of xylitol and the process dynamics. A multi-stage approach is used to develop a customized model which is able to support the process synthesis and design for the biorefinery including performance prediction, sizing and costing analysis. To this end the model accounts for various process phenomena from different scale levels such as biological (e.g. the specific metabolism), chemical (e.g. acid-base equilibria) and physical (e.g. gas-liquid mass transfer) in a fermentation reactor.