Exploring coaggregation mechanisms involved in biofilm formation in drinking water through a proteomic-based approach.

Aim: Coaggregation, a highly specific cell-cell interaction mechanism, plays a pivotal role in multispecies biofilm formation. While it has been mostly studied in oral environments, its occurrence in aquatic systems is also acknowledged. Considering biofilm formation's economic and health-related implications in engineered water systems, it is crucial to understand its mechanisms.

Sulfamethoxazole is Metabolized and Mineralized at Extremely Low Concentrations.

The presence of organic micropollutants in water and sediments motivates investigation of their biotransformation at environmentally low concentrations, usually in the range of μg L. Many are biotransformed by cometabolic mechanisms; however, there is scarce information concerning their direct metabolization in this concentration range. Threshold concentrations for microbial assimilation have been reported in both pure and mixed cultures from different origins.

Environmental proteomics as a useful methodology for early-stage detection of stress in anammox engineered systems.

Anammox bacteria are widely applied worldwide for denitrification of urban wastewater. Differently, their application in the case of industrial effluents has been more limited. Those frequently present high loads of contaminants, demanding an individual evaluation of their treatability by anammox technologies.

Thermal hydrolysis pre-treatment has no positive influence on volatile fatty acids production from sewage sludge.

The study compares the potential to produce volatile fatty acids (VFA) from sewage sludge, both raw and thermally pre-treated in two modes of operation. In batch mode, raw sludge at pH 8 obtained the highest maximum VFA yield (0.41 g COD-VFA/g CODfed) whereas pre-treated sludge achieved a lower value (0.

Sulfamethoxazole Enhances Specific Enzymatic Activities under Aerobic Heterotrophic Conditions: A Metaproteomic Approach.

The growing concern about antibiotic-resistant microorganisms has focused on the sludge from wastewater treatment plants (WWTPs) as a potential hotspot for their development and spread. To this end, it seems relevant to analyze the changes on the microbiota as a consequence of the antibiotics that wastewater may contain. This study aims at determining whether the presence of sulfamethoxazole (SMX), even in relatively low concentrations, modifies the microbial activities and the enzymatic expression of an activated sludge under aerobic heterotrophic conditions.

Enzymatic cometabolic biotransformation of organic micropollutants in wastewater treatment plants: A review.

Biotransformation of trace-level organic micropollutants (OMPs) by complex microbial communities in wastewater treatment facilities is a key process for their detoxification and environmental impact reduction. Therefore, understanding the metabolic activities and mechanisms that contribute to their biotransformation is essential when developing approaches aiming to minimize their discharge. This review addresses the relevance of cometabolic processes and discusses the main enzymatic activities currently known to take part in OMPs removal under different redox environments in the compartments of wastewater treatment plants.

Elimination of SARS-CoV-2 along wastewater and sludge treatment processes.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is shed in the feces of infected people. As a consequence, genomic RNA of the virus can be detected in wastewater. Although the presence of viral RNA does not inform on the infectivity of the virus, this presence of genetic material raised the question of the effectiveness of treatment processes in reducing the virus in wastewater and sludge.

Heterotrophic enzymatic biotransformations of organic micropollutants in activated sludge.

While heterotrophic microorganisms constitute the major fraction of activated sludge biomass, the role of heterotrophs in the biotransformation of organic micropollutants (OMPs) has not been fully elucidated. Yet, such knowledge is essential, particularly when conceiving novel wastewater treatment plants based on a two-stage process including an A-stage under heterotrophic conditions and a B-stage based on anammox activity. Biotransformation of OMPs in activated sludge is thought to mostly occur cometabolically thanks to the action of low specificity enzymes involved in the metabolism of the primary substrates.

The fate of SARS-COV-2 in WWTPS points out the sludge line as a suitable spot for detection of COVID-19.

SARS-CoV-2 genetic material is detectable in the faeces of a considerable part of COVID-19 cases and hence, in municipal wastewater. This fact was confirmed early during the spread of the COVID-19 pandemic and prompted several studies that proposed monitoring its incidence by wastewater. This paper studies the fate of SARS-CoV-2 genetic material in wastewater treatment plants using RT-qPCR with a two-fold goal: i) to check its presence in the water effluent and in the produced sludge and ii) based on the understanding of the virus particles fate, to identify the most suitable spots for detecting the incidence of COVID-19 and monitor its evolution.

Microbial inefficient substrate use through the perspective of resource allocation models.

Microorganisms extract energy from substrates following strategies that may seem suboptimal at first glance. Beyond the so-called yield-rate trade-off, resource allocation models, which focus on assigning different functional roles to the limited number of enzymes that a cell can support, offer a framework to interpret the inefficient substrate use by microorganisms. We review here relevant examples of substrate conversions where a significant part of the available energy is not utilised and how resource allocation models offer a mechanistic interpretation thereof, notably for open mixed cultures.

Chemical and thermal stabilization of CotA laccase via a novel one-step expression and immobilization in muNS-Mi nanospheres.

A methodology that programs eukaryotic or bacterial cells to encapsulate proteins of any kind inside micro/nanospheres formed by muNS-Mi viral protein was developed in our laboratory. In the present study such "in cellulo" encapsulation technology is utilized for immobilizing a protein with an enzymatic activity of industrial interest, CotA laccase. The encapsulation facilitates its purification, resulting in a cost-effective, one-step way of producing immobilized enzymes for industrial use.

"Who Cares?": The Acceptance of Decentralized Wastewater Systems in Regions without Water Problems.

There is a growing interest in decentralized wastewater treatment systems, especially in regions with water scarcity problems or water management issues. This study aims to determine whether the perceived advantages and disadvantages (leading to acceptance) of decentralized wastewater plants in such regions are the same in regions where the population is not aware of these water issues. Firstly, this study systematically reviews previous findings on public perceptions of the acceptance of decentralized wastewater treatment systems.

The organic loading rate affects organic micropollutants' cometabolic biotransformation kinetics under heterotrophic conditions in activated sludge.

Several studies have shown that organic micropollutants (OMPs) are biotransformed cometabolically in activated sludge systems. However, the individual role of heterotrophs in the microbial consortium is still not clear, i.e.

Resource allocation explains lactic acid production in mixed-culture anaerobic fermentations.

Lactate production in anaerobic carbohydrate fermentations with mixed cultures of microorganisms is generally observed only in very specific conditions: the reactor should be run discontinuously and peptides and B vitamins must be present in the culture medium as lactic acid bacteria (LAB) are typically auxotrophic for amino acids. State-of-the-art anaerobic fermentation models assume that microorganisms optimise the adenosine triphosphate (ATP) yield on substrate and therefore they do not predict the less ATP efficient lactate production, which limits their application for designing lactate production in mixed-culture fermentations. In this study, a metabolic model taking into account cellular resource allocation and limitation is proposed to predict and analyse under which conditions lactate production from glucose can be beneficial for microorganisms.

Energy requirements and economics of acetone-butanol-ethanol (ABE) extractive fermentation: a solvent-based comparative assessment.

The reindustrialization of acetone-butanol-ethanol (ABE) fermentation is hampered by its significant production cost, linked to high product inhibition and low product yield. ABE fermentation can be significantly enhanced by integrating in situ liquid-liquid extraction. In this study, hybrid simulations using Excel and ASPEN Plus were performed based on solvent-dependent experimental data (product titer, yield and productivity) to consider the physiological response of the microorganism in specific extractive ABE fermentations, and to quantify the energy requirements and the economic improvement of the overall process.

Protein composition determines the preferential consumption of amino acids during anaerobic mixed-culture fermentation.

The valorisation of protein-rich residual streams by anaerobic mixed-culture fermentation (MCF) has been barely studied in contrast to carbohydrate-rich wastes. The aim of this work was, therefore, to investigate how protein composition, i.e.

Purple phototrophic bacteria for resource recovery: Challenges and opportunities.

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).

Assessment of the fate of organic micropollutants in novel wastewater treatment plant configurations through an empirical mechanistic model.

Novel wastewater treatment plants (WWTPs) are expected to be less energetically demanding than conventional ones. However, scarce information is available about the fate of organic micropollutants (OMPs) in these novel configurations. Therefore, the objective of this work is to assess the fate of OMPs in three novel WWTP configurations by using a plant-wide simulation that integrates multiple units.

Acidogenesis is a key step in the anaerobic biotransformation of organic micropollutants.

Understanding the role of the different anaerobic digestion stages on the removal of organic micropollutants (OMPs) is essential to mitigate their release from wastewater treatment plants. This study assessed the fate of 21 OMPs during hydrolysis and acidogenesis to elucidate the contribution of these stages to the overall anaerobic removal. Moreover, the removal mechanisms and factors influencing them were investigated.

A metabolic model for targeted volatile fatty acids production by cofermentation of carbohydrates and proteins.

Anaerobic mixed-culture fermentations are interesting processes to valorise organic wastes by converting them to volatile fatty acids. One of the main issues is that certain operational conditions (e.g.

Comprehensive comparison of chemically enhanced primary treatment and high-rate activated sludge in novel wastewater treatment plant configurations.

Novel wastewater treatment plants (WWTPs) are designed to be more energy efficient than conventional plants. One approach to becoming more energy efficient is the pre-concentration of organic carbon through chemically enhanced primary treatment (CEPT) or high-rate activated sludge (HRAS). This study compares these approaches in terms of energy demand, operational costs, organic micropollutants (OMP), and virus removal efficiency.

Metabolic modeling for predicting VFA production from protein-rich substrates by mixed-culture fermentation.

Proteinaceous organic wastes are suitable substrates to produce high added-value products in anaerobic mixed-culture fermentations. In these processes, the stoichiometry of the biotransformation depends highly on operational conditions such as pH or feeding characteristics and there are still no tools that allow the process to be directed toward those products of interest. Indeed, the lack of product selectivity strongly limits the potential industrial development of these bioprocesses.

Air-side ammonia stripping coupled to anaerobic digestion indirectly impacts anaerobic microbiome.

Air-side stripping without a prior solid-liquid phase separation step is a feasible and promising process to control ammonia concentration in thermophilic digesters. During the process, part of the anaerobic biomass is exposed to high temperature, high pH and aerobic conditions. However, there are no studies assessing the effects of those harsh conditions on the microbial communities of thermophilic digesters.