Dual Doctoral Degree

In 2013 TU Delft and University of Campinas (Brazil) initiated a “Dual Degree PhD program” focused on “biobased economy”. Within this framework, we have three PhD projects in progress:

Sustainability assessment of a thermo-biochemical hybrid pathway for the production of second generation ethanol

Elisa de Medeiros, PhD student

This project aims to explore the sustainable production of second generation ethanol via gasification-fermentation hybrid route. The two main conversion processes combined in this pathway, i.e. biomass gasification to syngas and further syngas fermentation to ethanol, are capable of providing several advantages, such as: full conversion of biomass components including recalcitrant lignin, feedstock flexibility, dismissal of complex biomass pretreatment and expensive enzymes, syngas conversion under mild conditions of temperature and pressure, and higher tolerance of microbial catalysts compared to metal catalysts commonly used in chemical conversion of syngas. This project aims to fill several research gaps with the top goal of providing insights on how to approach energy efficiency and sustainability within this route. To achieve this goal, the project is divided in three layers. First, special attention is given to the fermentation of syngas with anaerobic bacteria due to the lack of consistent data in the literature. This process is studied via two approaches: (i) a dry lab investigation through dynamic flux balance models which employ genome-scale reconstruction, already available in the literature for Clostridium ljungdahlii, and dynamics of kinetics and mass transfer; and (ii) wet lab experiments of syngas fermentation for adjustment of parameters, improvement and validation of computational models. The second layer encompasses the design and simulation of integrated processes using commercial software Aspen plus and considering different technological alternatives. Finally, in order to locate hotspots for improvement and compare the alternatives, the simulations undergo sustainability assessments consisting of: (i) Life Cycle Assessment; (ii) financial analysis; and (iii) exergy analysis.

Syngas fermentation for large-scale ethanol production: early-stage technical and sustainability assessment for optimum combination between syngas production/ supply and fermentation

Eduardo Almeida, PhD student

This project aims to provide an assessment on the manner of integrating syngas supply with its subsequent fermentation, for large-scale ethanol production. For this, experiments will be carried out on gasification of different raw materials. The obtained compositions will be linked to two types of mathematical models representing the behavior of bacteria during syngas fermentations: a thermodynamic model, to check ranges of concentrations, fermentor conditions and configurations under which ethanol production is feasible and favored over acetate production; and a kinetic metabolic model which will be built to evaluate the cyclic dynamic metabolic response over substrate concentration gradients inside large-scale reactors operating at steady-state conditions. This assessment will finally be used for the identification of potential targets of metabolic engineering for improving the robustness of bacteria, and finally produce a strongly supported bioreactor and gasification process designs, which will be used to evaluate the performance of the whole ethanol large-scale production plant in terms of integrated sustainability.