Pamela Ceron Chafla
Master’s degree in Environmental Technology and Engineering (IMETE) from Unesco IHE, UCT Prague and Ghent University (2012-2014)
Thesis: Optimization of a two-stage fermentation process for PHB production
Bachelor’s degree in Environmental Engineering from Universidad San Francisco de Quito (Ecuador) with a minor degree in Chemical Engineering (2006-2012)
Graduation project: Physicochemical treatment system for tannery effluents
Working experience as National/international Environmental Consultant, lecturer in Life Cycle Assessment, Field Engineer and Research Assistant
Pamela on LinkedIn
Pamela on Researchgate
Autogenerative High Pressure Anaerobic Digestion systems (AHPD) have been used to produce biogas with improved quality (90-95% methane content) and at a pressure suitable for high grade use. This technology has also proven to produce other metabolites (carboxylates), that by themselves or through further conversion, could be of interest for the chemical industry. It is expected that specific pressure effects influence the kinetics of mixed culture fermentations (e.g. role of the CO2 partial pressure) and eventually the product spectrum. This project aims to further address these effects and determine to what extent they can be exploited to improve the production yield and increase the selectivity of a HPD system for carboxylates production. The feasibility of treating simple and complex substrates, mechanisms for controlling the product spectrum as well as the requirements for process parameters optimization, reactor design and alternatives for downstream processing will be further addressed along the research.
Status PhD
- PhD successfully defended
- Supervisors / promoters : Prof.dr.ir. Jules B. van Lier, Dr.ir. Ralph E.F. Lindeboom (both TU Delft), Prof.dr.ir. Korneel Rabaey (UGent)
- Final title of the PhD thesis : Steering Product Formation in High-Pressure Anaerobic Digestion Systems; the role of elevated partial pressure of carbon dioxide (pCO2)
- Place and date of PhD defense: Delft University of Technology, Delft, The Netherlands, Thursday 14 July 2022
- PhD degree awarding institutions: Delft University of Technology (principal), University of Gent (co-awarding)
Publications arising from the PhD
- Ceron P., C. Garcia, R. Kleerebezem, K. Rabaey, J. B. van Lier, and R.E.F. Lindeboom, (2020). Direct and indirect effect of increased CO2 partial pressure on the bioenergetics of syntrophic propionate and butyrate conversion. Env. Sci. & Technol., DOI: https://doi.org/1021/acs.est.0c02022, 54(19), 12583-12592.
- Ceron-Chafla P., Y. Chang, K. Rabaey, J.B. van Lier, and R.E.F. Lindeboom (2021). Directional selection of microbial community reduces propionate accumulation in glycerol and glucose mixed culture fermentations under elevated pCO2. Frontiers in Microbiology, section Microbiotechnology, Vol 12, 675763; https://doi.org/10.103389/fmicb.2021.675763
- Ceron-Chafla P., C. Garcia-Timmermans, J. de Vrieze, R. Ganigue, N. Boon, K. Rabaey, J.B. van Lier, and R.E.F. Lindeboom (2022). Pre‐incubation conditions determine the fermentation pattern and microbial community structure in fermenters at mild hydrostatic pressure. Biotechnol Bioeng. 1792-1807, https://doi.org/10.101002/bit.28085
- De Crescenzo C., A. Marzocchella, D. Karatza, A. Molino, P. Ceron-Chafla, R.E.F. Lindeboom, J.B. van Lier, S. Chianese, D. Musmarra (2022). Modelling of autogenerative pressurised anaerobic digestion in a batch reactor for the production of pressurised biogas. Biotechnol. for Biofuels, 15(1), 20, https://doi.org/10.1186/s13068-022-02117-x
- Ceron-Chafla, J. de Vrieze, R. Ganigue, K. Rabaey, J.B. van Lier, and R.E.F. Lindeboom (2023). Steering the product spectrum in high-pressure anaerobic processes; a novel tool in bio-refinery concepts. Biotechnol for Biofuels Bioproducts, Rebuttal submitted.
Link to PhD thesis
Short abstract/summary
Anaerobic processes such as Anaerobic Digestion (AD) and mixed culture fermentation (MCF) are important technologies in the bioeconomy context since they can be used to convert (waste) biomass feedstock into gaseous energy carriers and chemical commodities, theoretically without the use of any additional energy source. AD is a multi-step bioconversion process pursuing organic matter stabilization whose final product, i.e., biogas, can be used as an energy source. On the other hand, MCF employs open mixed cultures under non-sterilized conditions to produce carboxylates, i.e., short and medium-chain organic acids, which will serve as chemical building blocks after downstream processing. Limitations of biogas production are associated with the low CH4 content (≈50-60%), presence of impurities (like H2S) and unsuitable final pressure for direct connection to national grids. Thus, in recent years, the topic of biogas upgrading to biomethane (i.e., CH4>90%) has gained momentum and in-situ and ex-situ alternatives have been proposed with differences in financial and technical viability as well as achieved final CH4 content. While for the carboxylate production, major limitations are associated with process selectivity, presence of trace pollutants and too low broth concentrations for direct application inducing a need for “wet” and energy-intensive downstream processing. High-Pressure Anaerobic digestion (HPAD) is an innovative technology designed for simultaneous digestion and biogas upgrading. HPAD takes advantage of the large differences in solubility between biogas constituents, i.e., CH4 and CO2. Consequently, CH4 will predominantly remain in the gas phase after a pressure increase, whereas ionisable gases like CO2 and H2S will increasingly dissolve in the liquid. Thus, from a biogas production perspective, the proposed technology accomplishes higher CH4 content in the gas phase at the cost of increased dissolved CO2 levels. The process's overall performance under elevated pCO2 has not been adequately addressed. Mechanistic explanations for the role of increased dissolved CO2 in the fermentation process remain speculative, partially due to the limited amount of published experimental work on high-pressure fermentation with open cultures. Since CO2 exerts multiple roles in biological systems, increased dissolved CO2 could impact the kinetic and energetic feasibility of the reaction chain in AD and MCF, as well as the microbial community dynamics. These effects constitute a notorious knowledge gap that requires urgent attention.
