Gabriel Capson-Tojo

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Verified

Gabriel verified their affiliation via an institutional email.

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• PhD
• Researcher at French National Institute for Agriculture, Food, and Environment (INRAE)

In modelling of complex organic substrates like sugarcane vinasse, glucose is assumed as the sole sugar source, despite the fact that it contains glucose and sucrose. While both substrates produce similar byproducts, the literature reports glucose fermentation as more stable. Sucrose fermentation is known for its instability, leading to a decline i...

Purple non-sulfur bacteria (PNSB) offer a sustainable alternative to current inefficient protein production systems thanks to their high yields. This study explored the potential of specialized diazotrophic PNSB open cultures for protein production, benchmarking their performance against ammonium-grown PNSB and other diazotrophs. While diazotrophic...

Anaerobic digestion (AD)-derived digestate can be used as an organic fertilizer or for soil amendment. However, its utilization for resource recovery raises valid biosafety concerns. Despite extensive research on the capacity of AD for pathogen reduction, the variability in results poses challenges for drawing definitive conclusions. To address thi...

Introduction Purple phototrophic bacteria (PPB) are a promising candidate for phototrophic production of value-added products from wastewater treatment. Its products are found to be the biomass (as fertilizer and single-cell protein for animal feed), polyhydroxyalkanoates (as bioplastic precursors), H2, pigments like carotenoids or bacteriochloroph...

1. Keywords Purple non-sulphur bacteria, purple phototrophic bacteria, microbial protein 2. Highlights • Mixed purple cultures can effectively fix N2 at N and COD yields close to 1 g·g-1 • Photoheterotrophic uptake rates up to 6.8 g COD·g COD-1 ·d-1 were obtained • The obtained fixation rates were much higher than expected • Crude protein contents...

the unique diazotrophic and phototrophic capabilities of purple phototrophic bacteria could provide a sustainable alternative to the current fossil-based food production systems. We show here that mixed purple non-sulphur bacteria cultures can fix at extremely high N and COD yields (average values of 0.99±0.03 and 0.89±0.02 gbiomass·gremoved-1), an...

In-situ biomethanation shows significant potential for enhancing biogas quality. The efficiency of this process relies on various factors, including organic loading rate and hydrogen injection frequency. Experiments were carried out to evaluate the impact of different organic loading rates on hydrogen consumption rate during in-situ biomethanation....

Uncertainty quantification is critical for ensuring adequate predictive power of computational models used in biology. Focusing on two anaerobic digestion models, this article introduces a novel generalized Bayesian procedure, called VarBUQ, ensuring a correct tradeoff between flexibility and computational cost. A benchmark against three existing m...

Biogas upgrading via biomethanation has been extensively studied recently, but the influence of organic loading rate on process performance remains to be fully understood. This is particularly significant because both organic loading rate and hydrogen injection can lead to volatile fatty acid accumulation during anaerobic digestion. This study inve...

The decarbonisation of industry based on the sustainable use of resources is one of the main objectives of our current society. To achieve this, rich-carbohydrate residual streams constitute a cost-effective feedstock from which hydrogen can be produced via dark fermentation (DF). In recent years, bench-scale testing has delivered encouraging resul...

Uncertainty quantification is critical for ensuring adequate predictive power of computational models used in biology. Focusing on two anaerobic digestion models, this article introduces a novel generalised Bayesian procedure, called VarBUQ, ensuring a correct tradeoff between flexibility and computational cost. A benchmark against three existing m...

Single cell protein (SCP) has emerged as an alternative protein source, potentially based on the recovery of carbon and nutrients from waste-derived resources as part of the circular economy. From those resources, gaseous substrates have the advantage of an easy sterilization, allowing the production of pathogen-free SCP. Sterile gaseous substrates...

Purple phototrophic bacteria (PPB) are a promising option for resource recovery due to the high biomass yields that their phototrophic metabolism allows 1 • The proof of concept of H 2 conversion by PPB has been recently realized using pure cultures 2 • The performance of enriched cultures has not been tested and it is needed to assess nutrient rec...

Single cell proteins (SCP) have emerged as an alternative protein source to partially alleviate the current problem of food scarcity. However, there is a need for the production of SCP from renewable and pathogen-free sources, such as gaseous streams. This study evaluated, for the first time, the use of enriched phototrophic purple bacteria (PPB) c...

The Anaerobic Digestion Model #1 (ADM1) is the most used model to simulate anaerobic digestion process nowadays. It aggregates biochemical and physicochemical equations in its structure. To apply this model for an acidogenic bioreactor, where the final products are volatile fatty acids (VFA) and hydrogen, some modifications in its structure are req...

Research related with green hydrogen is increasing over the years due to the eminent necessity of renewable sources of energy. In this context, the development of mathematical models has contributed to a better understanding of the metabolic pathways involved in anaerobic digestion processes, thus facilitating the simulation in other scenarios. The...

Purple phototrophic bacteria (PPB) can produce single-cell protein from wastewater at high yields. Growing in a biofilm vs. suspended can improve product quality and consistency. This study compares suspended and attached growths of enriched PPB cultures in an outdoor flat plate photobioreactor treating poultry-processing wastewater. Attached growt...

Relevance and Goals Wastewater utilities are undertaking a future task to transform treatment plants into water resource recovery facilities (WRRFs). The aim is to produce energy (biofuels), valuable products, and nutrients such as fertilizers as well as regenerated water. Integrated approaches for "Water-Sludge-Energy" cooperation are a sustainabl...

The economic feasibility of purple phototrophic bacteria (PPB) for resource recovery relies on using enriched-mixed cultures and sunlight. This work presents an extended Photo-Anaerobic Model (ePAnM), considering: (i) the diverse metabolic capabilities of PPB, (ii) microbial clades interacting with PPB, and (iii) varying environmental conditions. K...

Purple phototrophic bacteria (PPB) have a great potential for resource recovery from wastewater thanks to their photoheterotrophic capabilities. This work puts together available information on PPB biochemical fundamentals and the latest results from pilot-scale PPB cultivation, aiming to point research towards realising PPB full-scale implementati...

Anaerobic digestion (AD) is a key technology in the current transition from a linear to a circular economy. As such, the number of AD plants has increased considerably in the last decade, and it is expected to further increase substantially in the coming years. This, together with the implementation of policies to foster resource recovery, call for...

If purple phototrophic bacteria (PPB)-based systems are to become a reality for resource recovery, research must be performed outdoors, using scaled reactors. Here we present the results from an outdoors 10 m long PPB-enriched flat plate photobioreactor (PBR), with a volume of 0.95 m3. Results show that, over a long period (192 days), the PBR was a...

Light attenuation in enriched purple phototrophic bacteria (PPB) cultures has not been studied, and its understanding is critical for proper process modelling and reactor design, especially for scaled systems. This work evaluated the effect of different biomass concentrations, reactor configurations, wastewater matrices, and growth conditions, on t...

PPB carotenoids are usually measured through spectrophotometric analysis, measuring total carotenoids (TCs) which has low accuracy and cannot identify individual carotenoids or isomers. Here, we developed an ultra-performance liquid chromatography method with ultraviolet and high-resolution mass spectrometry detection (UPLC-UV-HRMS) to quantify neu...

Mixed culture purple phototrophic bacteria (PPB) is a rapidly emerging technology for resource recovery from wastewaters. PPB biomass can be used as single-cell protein, with a high protein content complemented by value-added components (e.g. pigments and polyhydroxyalkanoates), merging functionalities within a single product. This has the potentia...

To make purple phototrophic bacteria (PPB)-based technologies a reality for resource recovery, research must be demonstrated outdoors, using scaled reactors. In this study, a 10 m long PPB-enriched flat plate photobioreactor (FPPBR) with a volume of 0.95 m³ was operated for 253 days, fed with poultry processing wastewater. Different operational str...

Resource recovery from wastewater, preferably as high value products, has become an integral part of modern wastewater treatment. This work presents the potential to produce single cell protein (SCP) from pre-settled piggery wastewater (PWW) and meat chicken processing wastewater (CWW), utilising anaerobic purple phototrophic bacteria (PPB). PPB we...

Ammoniacal nitrogen and long chain fatty acids (LCFA) are common inhibitors of the anaerobic digestion process. However, the interaction between these inhibitors has received little attention. Understanding the interaction between these inhibitors is important to optimise the operation of anaerobic digesters treating slaughterhouse waste or using f...

Light attenuation in purple phototrophic bacteria (PPB) has been studied. The results show that increased biomass concentrations lead to higher light attenuation, and that PPB absorb both visible and near-infrared wavelengths. Both spectrum fractions were equally absorbed at PPB concentrations above 1 g COD·L-1. A flat plate configuration showed le...

A comprehensive mechanistic model applicable for PPB-enriched cultures grown outdoors is proposed here, as an extension of the PAnM model (Puyol et al., 2017): the Photo-Anaerobic Model 2 (PAnM2). Relevant microbial clades interacting with PPB have been included, and the PPB metabolism has also been extended (e.g. including aerobic capabilities or...

Current mechanistic anaerobic digestion (AD) models cannot accurately represent the underlying processes occurring during food waste (FW) AD. This work presents an update of the Anaerobic Digestion Model no. 1 (ADM1) to provide accurate estimations of free ammonia concentrations and related inhibition thresholds, and model syntrophic acetate oxidat...

Purple phototrophic bacteria are receiving increasing attention due to their unique capability of growing photoheterotrophically, using energy from light to simultaneously recover carbon and nutrients in the form of a different value-added products. In this work, PPB-based applications and potential products are reviewed to identify major challenge...

The need for sustainable development is driving a major focus shift in the biowaste treatment sector. While traditional practices such as landfilling are progressively being banned/penalised due to their obvious environmental impacts and prevention policies are being implemented, the potential of food waste (FW) as a resource is being increasingly...

There is an ongoing debate around the effect of microaerobic/aerobic conditions on the wastewater treatment performance and stability of enriched purple phototrophic bacteria (PPB) cultures. It is well known that oxygen-induced oxidative conditions inhibit the synthesis of light harvesting complexes, required for photoheterotrophy. However, in appl...

The aim of this study was to assess the importance of two major modifications of the IWA ADM1 on its ability to model food waste anaerobic digestion: (i) estimating free ammonia nitrogen using a modified Davies equation and (ii) including syntrophic acetate oxidation as main acetate-consuming pathway. The obtained results show that, in agreement wi...

Sustainable development is driving a rapid focus shift in the wastewater and organic waste treatment sectors, from a “removal and disposal” approach towards the recovery and reuse of water, energy and materials (e.g. carbon or nutrients). Purple phototrophic bacteria (PPB) are receiving increasing attention due to their capability of growing photoh...

On-line performance indicators of a microalgae-bacteria consortium were screened out from different variables based on pH and dissolved oxygen on-line measurements via multivariate projection analysis, aiming at finding on-line key state indicators to easily monitor the process. To fulfil this objective, a pilot-scale high-rate pond for urban waste...

The objective of this study was to evaluate the performance of an outdoor membrane-coupled high-rate algal pond equipped with industrial-scale membranes for treating urban wastewater. Decoupling biomass retention time (BRT) and hydraulic retention time (HRT) by membrane filtration resulted in improved process efficiencies, with higher biomass produ...

This review aims at providing a unified methodology for free ammonia nitrogen (FAN) calculation in anaerobic digesters, also identifying the factors causing the huge disparity in FAN inhibitory limits. Results show that assuming ideal equilibria overestimates the FAN concentrations up to 37% when compared to MINTEQA2 Equilibrium Speciation Model, u...

The increasing production of food waste (FW) worldwide and the recent application of international regulations call for the development of novel strategies for the valorization of this biomass. Among the different options, anaerobic digestion (AD) is a promising alternative that offers an efficient waste treatment, together with its valorization in...

Ammonia nitrogen, particularly in its free form (NH3), is a major inhibitor in the anaerobic digestion of organic wastes. Besides its importance, a wide variation in the reported inhibitory limits exists. This study aimed at calculating different inhibitory limits using data retrieved from the literature, unifying the presented results and linking...

De nouvelles réglementations internationales et une production croissante des biodéchets alimentaires (BA) ont comme conséquence un besoin de développer de nouvelles filières pour la valorisation de ce déchet. La digestion anaérobie (DA) est une option très prometteuse qui permet un traitement efficace permettant la production de méthane et de dige...

This study describes a model-based method for real-time optimization of the key filtration parameters in a submerged anaerobic membrane bioreactor (AnMBR) treating urban wastewater (UWW) and UWW mixed with domestic food waste (FW). The method consists of an initial screening to find out adequate filtration conditions and a real-time optimizer appli...

BACKGROUND Although anaerobic digestion is a promising alternative for the valorization of complex substrates such as food waste, this process is yet to be optimized and options for its stabilization must be developed. This study assessed for the first time if the combined addition of biochar and trace elements in the form of an industrial FeCl3 so...

The objective of this study was to develop an advanced control system for optimizing the performance of fixed-bed anaerobic reactors. The controller aimed at maximizing the bio-methane production whilst controlling the volatile fatty acids content in the effluent. For this purpose, a fuzzy-logic controller was developed, tuned and validated in an a...

The increasing production of food waste (FW) worldwide and the recent application of international regulations call for the development of novel strategies for the valorization of this biomass. Among the different options, anaerobic digestion (AD) is a promising alternative that offers an efficient waste treatment, together with its valorization in...

Anaerobic digestion of food waste is a complex process often hindered by high concentrations of volatile fatty acids and ammonia. Methanogenic archaea are more sensitive to these inhibitors than bacteria and thus the structure of their community is critical to avoid reactor acidification. In this study, the performances of three different inocula w...

The effect of supplementing granular activated carbon and trace elements on the anaerobic digestion performance of consecutive batch reactors treating food waste was investigated. The results from the first batch suggest that addition of activated carbon favored biomass acclimation, improving acetic acid consumption and enhancing methane production...

This study evaluated the influence of the co-substrate proportions (0-60% of cardboard in dry basis) and the initial total solid contents (20-40%) on the batch fermentation performance. Maximum hydrogen yields were obtained when mono-fermenting food waste at high solids contents (89 ml H2·gVS⁻¹). The hydrogen yields were lower when increasing the p...

Hydrogen production by biological methods, particularly dark fermentation, has recently gained in interest for the scientific as well as the socio-economic communities. This theme has been intensively investigated over the past decade since biohydrogen can be produced under a large range of conditions. This chapter aims to present the basic concept...

The increasing production of food waste worldwide and new international regulations call for the development of novel processes for the treatment of this waste. Among all the existing possibilities, anaerobic processes represent a sustainable-modern approach that allows waste treatment and valorization. This PhD thesis aims at understanding the bio...

Critical importance of the presence of Methanosarcina in the microbial inoculum for achieving an efficient start-up of the anaerobic digestion process when using food waste as substrate.

Dry anaerobic digestion is a promising option for food waste treatment and valorization. However, it is a complex process, often associated with accumulation of volatile fatty acids and ammonia nitrogen. This is translated into inefficient processes and even digestion failure. Co-digestion with cardboard may be a solution to this problem. This stud...

Dry anaerobic digestion is a promising option for food waste treatment and valorization. However, accumulation of ammonia and volatile fatty acids often occurs, leading to inefficient processes and digestion failure. Co-digestion with cardboard may be a solution to overcome this problem. The effect of the initial substrate to inoculum ratio (0.25 t...

The objective of this study was to test three different alternatives to mitigate the destabilizing effect of accumulation of ammonia and volatile fatty acids during food waste anaerobic digestion. The three options tested (low temperature, co-digestion with paper waste and trace elements addition) were compared using consecutive batch reactors. Alt...

Des nouvelles règlementations nationales et une production croissante des biodéchets alimentaires (BA) ont comme conséquence un besoin de développer des nouvelles filières de valorisation. Parmi les technologies qui peuvent permettre de répondre à cette problématique, la digestion anaérobie (DA) est une option très prometteuse qui permet un traitem...

The increasing food waste production calls for developing efficient technologies for its treatment. Anaerobic processes provide an effective waste valorization. The influence of the initial substrate load on the performance of batch dry anaerobic co-digestion reactors treating food waste and cardboard was investigated. The load was varied by modify...

Due to population and economic growth, the production of food waste (FW) is increasing worldwide. This, together with new international regulations, causes the need of developing new technologies that allow a proper valorization of this waste. Anaerobic digestion (AD) is a well-known option that can efficiently treat organic wastes, producing value...

The increasing production of food waste worldwide and new international regulations call for the development of new technologies to treat this biowaste. Anaerobic processes are able to treat efficiently organic wastes, producing at the same time different value-added compounds. In addition, due to the lower costs and environmental impacts associate...

Nowadays, about 1.3 billion tons of food is wasted every year. This number, which is expected to increase greatly in the next decades, evidences the urgent need of improving the efficiency of the current food processing systems, supply chains, prevention policies and food waste (FW) disposal alternatives. Indeed, new FW treatment methods must be de...

Nowadays, about 1.3 billion tons of food is wasted every year. This number, which is expected to increase greatly in the next decades, evidences the urgent need of improving the efficiency of the current food processing systems, supply chains, prevention policies and food waste (FW) disposal alternatives. Indeed, new FW treatment methods must be de...

The effect of lipid extraction on anaerobic digestion was evaluated considering microalgae N.gaditana. Anaerobic digestion of total and spent microalgae was carried out under mesophilic and thermophilic conditions. The results indicated that anaerobic degradability increased when spent microalgae was used as substrate for both anaerobic conditions....