Raman microscopy for phenotyping microbial microorganisms

Post date: Wednesday, 16 September, 2020 - 11:48

Abstract of the doctoral research of Cristina García-Timermans:

Single cell phenotypic differences arise even in monoclonal populations. This allows them to survive, increase their fitness or organize the spatial structure of the population. However, the methods most commonly used to study microbial populations (i.e., sequencing techniques and omics) analyse all the cells of the same sample together in bulk. Although this is valuable information, bulk techniques only inform on the average behaviour of populations, masking single-cell heterogeneity.
In this thesis, we discuss the use of Raman spectroscopy as a single-cell tool to study bacterial phenotypic heterogeneity. First, we propose a standard way to acquire and report Raman spectra. Secondly, we compare the resolution of Raman spectroscopy with another single-cell tool, flow cytometry. Thirdly, we automatically define phenotypes based on their Raman spectra using dimensionality reduction and/or clustering methods. Then, we quantify single-cell phenotypic diversity using the Hill diversity framework with Raman spectra. Finally, we show how these tools can be used as screening and monitoring tools in bioproduction. Raman spectroscopy presents an opportunity to study phenotypic heterogeneity at the single-cell level and to describe, explain, predict and manage microbial communities.

Dissertation Supervisors:

 Prof. Dr. Ir. Nico Boon and Prof. Dr. ir. Ruben Props.

Event location: Virtual Event
Event date: Friday, 9 October, 2020 - 16:00

Microbial protein production by autotrophic nitrogen-fixing hydrogen-oxidizing bacteria

Post date: Wednesday, 16 September, 2020 - 10:52

Abstract of the doctoral research of Xioana Hu:

Food production will need to be increased in response to the growing world population and rising demand for high grade protein per capita. Due to the inefficient use of energy-intensive nitrogen fertilizers in contemporary agriculture and main nitrogen losses as manure during plant-livestock conversion, further expansion of traditional agricultural practices will exacerbate its environmental damage. Therefore, the interest in microbial protein produced by hydrogen-oxidizing bacteria has been renewed due to its potential to be integrated into food chain. However, the high demand of nitrogen fertilizers derived from the Haber-Bosch process remains environmentally stressful.
This thesis explored the potential of using autotrophic nitrogen-fixing hydrogen-oxidizing bacteria to produce microbial protein as an alternative to protein source from food and feed. An enriched microbial community was used to demonstrate the protein quality and yield of the proposed process. Then pure cultures were obtained from the community to study its microbial ecology. The possible roles and interactions of diverse isolates in the community were studied using genome comparison and synthetic communities.
The proposed process could produce high-quality protein with an energy conversion efficiency higher than that of soybean. Understanding of the microbial ecology of the enriched community will contribute to the microbial resource management for more efficient biomass production.

Dissertation Supervisors:

 Prof. Dr. Ir. Nico Boon and, Dr. ir. Peter Clauwaert

Event location: Virtual Event
Event date: Monday, 12 October, 2020 - 16:00

Urine treatment technologies for a circular future within and beyond terrestrial boundaries

Post date: Wednesday, 16 September, 2020 - 10:42

Abstract of the doctoral research of Jolien De Paepe:

Human presence in outer Space is currently supported by a regular resupply of water and food from Earth. As this becomes impossible for long distances, deep-space exploration or space habitation will depend on regenerative life support systems (RLSS) for in-situ oxygen, water and food production and waste management. Urine recycling is of key interest in RLSS to recover water and nutrients, which can serve as a fertilizer for plants and microalgae. Urine source separation and recycling also gains attention on Earth to close and/or shorten the terrestrial nutrient cycles, which play a pivotal role in our food supply, but are currently pushed to their planetary boundaries by extensive synthetic fertilizer production and use. Urine contains many valuable compounds, but the compositional complexity of urine also presents a challenge for urine treatment and recycling. Different urine treatment trains combining biological and physicochemical processes were explored in this PhD thesis. Three main treatment steps were considered:

  1. Alkalinization through chemical or electrochemical hydroxide addition to prevent urea hydrolysis during collection and storage,
  2. Biostabilization in a microbial electrolysis cell and membrane aerated biofilm reactor or moving bed biofilm reactor to transform urine into a stable nitrate-rich urine solution low in organics, suitable for plant or microalgae cultivation,
  3. Concentration of the nitrified urine through electrodialysis or an electrochemical cell or valorization through microalgae cultivation in a photobioreactor.

These novel resource-efficient urine treatment trains maximize nutrient recovery while minimizing the use of consumables which could advance nitrogen recovery on Earth and could push the development of RLSS for long-term human spaceflights.

Dissertation Supervisors:

 Prof. Dr. Ir. Korneel Rabaey, Prof. Dr. ir. Siegfried Vlaeminck,  Dr. ir. Peter Clauwaert, Prof. Dr. Francesc Gòdia Casablancas

Event location: Virtual Event
Event date: Wednesday, 14 October, 2020 - 17:00

Ozone-based Advanced Oxidation Processes for Trace Organic Contaminants Removal in (Waste)water: Kinetic Assessment and Improvement of Oxidant Exposure

Post date: Wednesday, 16 September, 2020 - 10:40

Abstract of the doctoral research of Ze Liu:


Dissertation Supervisors:


Prof. Dr. Ir. Stijn Van Hulle and Prof. Dr. ir. Kristof Demeestere

Event location: Virtual Event
Event date: Tuesday, 20 October, 2020 - 16:00

Wastewater treatment with aerobic granular sludge: challenges and opportunities for modelling and off-gas analyses

Post date: Friday, 1 May, 2020 - 15:01

Abstract of the doctoral research of Janis Baeten


Dissertation Supervisors:

 Prof. Dr. Ir. Eveine Volcke, Prof. Dr. ir. Mark van Loosdrecht

Event location: Virtual Event
Event date: Monday, 29 June, 2020 - 16:00

CAPTURE-Water / R2T Yearly Showcase

Post date: Monday, 3 February, 2020 - 14:37

In good tradition, the yearly showcase of the R2T consortium of CAPTURE-Water is held on February 18th, 2020. During this day representatives of platform companies connect with researchers for an exciting day of knowledge exchange.

This day is only open for member companies and connected research staff.

9h00-12h00        Topical meetings to develop research programs

12h00    Lunch                 
13h00    Welcome and introduction
13h05    CAPTURE-Water showcase

  • Overview R2T & CAPTURE-WATER
    • General update on CAPTURE developments
    •  Project highlights of CAPTURE-Water
    • Societal impact of CAPTURE-Water
  •  Introduction of 6 new professors that have joined CAPTURE-Water
  • New company introductions

14h15            Break
14h40    Project highlight presentations (Part I)
15h30            Break
15h50    Project highlight presentations (Part II)
16h10    Closing lecture    
16h30    Short reception + Posters
18h30-22h00    Walking dinner

Event location: Coupure Campus, UGent
Event date: Tuesday, 18 February, 2020 - 09:00 to 22:00

Green chemistry for a circular economy

Post date: Tuesday, 21 January, 2020 - 15:11

On the occasion of the PhD defense of Pieter Naert, Prof. James Clark from York University will hold a lecturen entitled 'Green chemistry for a circular economy'

Event location: Coupure Campus, UGent
Event date: Thursday, 6 February, 2020 - 10:30

Downstream processing of bio-derived short-chain carboxylic acids via esterification

Post date: Tuesday, 21 January, 2020 - 15:10

Abstract of the doctoral research of Pieter Naert:

The production of biogas from the organic matter in waste streams is an established technology for value creation from waste, albeit in the form of low value energy. Since a number of years, research has focused on steering this microbial degradation process towards the production of organic acids, which can be used as building blocks for renewable products, with a higher value than biogas. However, the current technologies do not allow cost-competitive recovery of the acids from the bioprocess. In this research project, a novel process was developed that allows recovery and simultaneous conversion to the corresponding esters. These esters have a higher value and an extensive market as solvents for the chemical industry and in paints and lacquers, and as fragrances in household products. During the PhD research, different unit operations were investigated and developed for this purpose, and integrated into a process. The continuous production of esters from a waste stream was demonstrated. In the final part, simulations of the process on industrial scale delivered insight on the feasibility and performance compared to alternative production methods.

Dissertation Supervisors:

 Prof. Dr. Ir. Korneel Rabaey, Prof. Dr. ir. Christian Stevens

Event location: Het Pand, Gent
Event date: Thursday, 6 February, 2020 - 17:00

Industrial demineralization and steam-water cycles

Post date: Tuesday, 21 January, 2020 - 15:09

On the occasion of the PhD defense of Evelyn De Meyer a seminar afternoon is organized:

13:00 Emmanuel Van Houtte (IWVA - Intercommunale Waterleidingsmaatschappij van Veurne-Ambacht)
13:30 Louise Vanysacker (De Watergroep)
14:00 Break
14:15 3 pitches

  •         Tim De Seranno  (Corrosion - metal integrity)  
  •         Yu Xue (Organic matter breakdown)  
  •         Jasmine Heyse (Flow cytometry)

14:30 David Moed (Evides Industriewater)
15:00 Marc Slagt (Dupont)
15:30 End

16:00 PhD defense Evelyn De Meyer - The behavior of organic matter in industrial demineralization and steam-water cycles

Event location: Coupure Campus, UGent; Room E4
Event date: Thursday, 5 March, 2020 - 13:00

The behavior of organic matter in industrial demineralization and steam-water cycles

Post date: Tuesday, 21 January, 2020 - 15:08

Abstract of the doctoral research of Evelyn De Meyer:

The impact of organic matter in crucial parts of the industrial steam-water cycle is the focus in this research. Not only the organic matter present in the water source for the production of boiler feed water is investigated, but also the addition of organic components during conditioning of the boiler feed water is taken into account. Alternative water sources (industrial waste water and surface water) were subjected to ion exchange demineralization to investigate a potential difference in TOC removal efficiency compared to a reference treatment with tap water. Next, the effect of both alkalizing and film forming amines on the condensate polishing unit and the formation of organic acids due to hydrothermolysis were investigated, respectively. In general, it is clear that the term “Total Organic Carbon” is anything but sufficient to describe the complex nature of organic matter present in steam-water cycles. In practice, it is not only about how much TOC is present in the boiler feed water, more important it is about what kind of TOC is present. Implementation of a more thorough scientifically based corrosivity guideline, concerning the organic matter present in a water stream, will ask for a change in mindset, both from an operational point of view and a manufacturer point of view.

Dissertation Supervisors:

 Prof. Dr. Ir. Arne Verliefde, Prof. Dr. ir. Kim Verbeken

Event location: Coupure Campus, UGent; Room A0.1
Event date: Thursday, 5 March, 2020 - 16:00


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