Task 2.1: Design, Construction of a novel bioreactor
A novel bioreactor configuration will be designed and constructed. The principal aim of the reactor design and operation will be the decrease of mass transfer limitations of the gas components (syngas) to the liquid phase. The effect of operational parameters and the reactors’ configuration on the process efficiency will be tested in lab-scale experiments during Tasks 2.2 and 2.3.
Task 2.2: Biomethanation of syngas
Subtask 2.2.1: Culture enrichments, lab-scale experiments with synthetic syngas. Samples from different methanogenic environments will be collected and used as inocula (starting microbial culture) for enriching mixed microbial consortia able to ferment syngas to CH4. The enriched microbial cultures will be kinetically characterized and subsequently transferred to a) a CSTR-type, b) a bio-film based reactor and c) the novel reactor constructed in task 2.1. Operational parameters that maximize the CH4 efficiency will be determined and the effect of the novel reactor configuration on the process efficiency will be assessed.
Subtask 2.2.2: On-site biomethanation of syngas. A bench scale bio-methanation unit will be installed at DGC to convert syngas from the gasifier (Workpackage 1)into biogas produced by microbes in the unit at the operating conditions obtained from subtask 2.2.1.
Task 2.3: Fermentation of syngas to alcohols.
Samples from different anaerobic environments will be screened for microbes able to ferment syngas to ethanol and/or higher alcohols (methanogenic samples will be thermally pre-treated in order to harvest the spore-forming Clostridia). The selected fermentative culture (based on products analysis and on data obtained from task 2.4) will be established in three types of bioreactors also mentioned in Subtask 2.2.1. The feasibility of mixed cultures application for alcohols production will be evaluated. The efficiency of the novel reactor configuration will be assessed as well. During the final phase of Task 2.3 one of the lab-scale reactors will be transferred to DGC premises and connected to the gasifier for performing on-site fermentation of syngas to alcohols.
Task 2.4: Analysis of microbial cultures and metabolic potential
After initial information on different consortia and their capacity to ferment syngas is obtained (data from task 2.3) the species composition of the most promising consortia will be analysed. A proprietary bioinformatics tool will be used for the assessment of the consortia metabolic potential (for alcohols production). This task will yield specific information of the organisms present in the syngas fermenting consortia and of their metabolic potential. This will allow selection of the optimal consortia for producing the desired products and help in optimizing the composition of the consortia.
Task 2.5: Mass transfer limitations (months 0-24)
Controlling the pressure or adding surfactants will be investigated as the main methods for improving the mass transfer from the gas to the liquid phase. Investigations will include both experimental studies and advanced thermodynamic modelling, including the solubility of syngas gases (individually and as a mixture) in water over extensive temperature and pressure conditions. Advanced thermodynamic models developed at DTU will be extended to syngas-water phase behaviour.
Coworkers:
- Hariklia Gavala (Assoc. prof. BIOENG)
- Lene Lange (BIOENG)
- Peter Kamp Busk (Senior researcher, BIOENG)
- Mateusz Lezyk (Postdoc, BIOENG)
- Antonio Grimalt Alemany (PhD student, BIOENG)
- Konstantinos Asimakopoulos (PhD student, PILOT PLANT)
- Zhiyou Wen (Assoc. prof., Iowa State University)
- Robert Brown (Professor, Iowa State University)