Eoin Casey

• PhD
• Professor at University College Dublin

The purpose of this study was to investigate the effects of calcium ions on the structural and mechanical properties of Pseudomonas fluorescens biofilms grown for 48 h. Advanced investigative techniques such as confocal laser scanning microscopy and atomic force spectroscopy were employed to characterize biofilm structure as well as biofilm mechani...

Analytics: A better look at biofilms Combining two distinct techniques allows analysis of the structure and physical properties of bacterial biofilms in fine detail. Eoin Casey and colleagues, from University College Dublin, Ireland, and the University of Hong Kong, applied a combined non-destructive procedure to cultured biofilms, for determining...

Diffusion of the electron acceptor is the rate controlling step in virtually all biofilm reactors employed for aerobic wastewater treatment. The membrane-aerated biofilm reactor (MABR) is a technology that can deliver oxygen at high rates and transfer efficiencies, thereby enhancing the biofilm activity. This paper provides a comparative performanc...

Herein, the fabrication of four different nanostructured silicon surfaces by using a combination of block copolymer micelle lithography is reported on. Nanoparticle hard masks are evaluated for their ability to produce single‐height nanoneedle arrays. Low‐density (3 features μm⁻²) and high‐density (201 features μm⁻²) single‐height arrays are produc...

Membrane biofilm reactors are a growing trend in wastewater treatment whereby gas-transfer membranes provide efficient bubbleless aeration. Recently, there has been a growing interest in using these bioreactors for industrial biotechnology using microorganisms that can metabolise gaseous substrates. Since gas fermentation is limited by the low solu...

The objective of this study is to develop an operation that can conduct separations based on diafiltration using semipermeable nanofiltration or ultrafiltration membranes in a fully continuous manner in a single stage configuration.

Increasing energy efficiency in wastewater treatment plants (WWTPs) is becoming more important. An emerging approach to addressing this issue is to exploit development in data science and modelling. Deployment of sensors to measure various parameters in WWTPs opens greater opportunities for exploiting the wealth of data. Artificial intelligence (AI...

Nanoparticles (NPs) are considered a promising tool in the context of biofilm control. Many studies have shown that different types of NPs can interfere with the bacterial metabolism and cellular membranes, thus making them potential antibacterial agents; however, fundamental understanding is still lacking on the exact mechanisms involved in these...

The dynamic nature of wastewater treatment and the significant number of energy conversion and recovery technologies applicable to the process, require a modelling framework that can be used for optimization and planning. This paper introduces a dynamic energy dispatch optimization framework with a combination of energy recovery and reserve options...

Enhancement of fluorescence through the application of plasmonic metal nanostructures has gained substantial research attention due to the widespread use of fluorescence-based measurements and devices. Using a microfabricated plasmonic silver nanoparticle–organic semiconductor platform, we show experimentally the enhancement of fluorescence intensi...

The modelling and optimization of a process for the production of the medium chain length polyhydroxyalkanoate (mcl‐PHA) by the bacterium Pseudomonas putida KT2440 when fed a synthetic fatty acid mixture (SFAM) was investigated. Four novel feeding strategies were developed and tested using a constructed model and the optimum one implemented in furt...

This study describes the oxidation of chlortetracycline (CTC) under nitrifying conditions in a membrane aerated biofilm reactor (MABR) in which microorganism uses as the electron acceptor and NH-N and CTC as the electron donors. The MABR was operated at various hydraulic retention time (HRTs), gas pressures and electron donors’ loadings. The result...

The potential of membrane bioreactors to produce value-added products such as biofuels, biopolymers, proteins, organic acids and lipids at high productivities is emerging. Despite the promising results at the laboratory, industrial deployment of this technology is hindered due to challenges associated with scale-up. This review aims to address thes...

This study describes the oxidation of chlortetracycline (CTC) under nitrifying conditions in a membrane aerated biofilm reactor (MABR) in which microorganism uses O2 as the electron acceptor and NH4+-N and CTC as the electron donors. The MABR was operated at various hydraulic retention time (HRTs), O2 gas pressures and electron donors’ loadings. Th...

A composition comprising a silica-based nanobead having its surface functionalized by a moiety selected from moieties that are reactive to and combine with a fouling layer on a material surface.

Background: The ubiquitous nature of bacterial biofilms combined with the enhanced resistance towards antimicrobials has led to the development of an increasing number of strategies for biofilm eradication. Such strategies must take into account the existence of extracellular polymeric substances, which obstruct the diffusion of antibiofilm agents...

Recent studies have shown that insect wings have evolved to have micro- and nanoscale structures on the wing surface, and biomimetic research aims to transfer such structures to application- specific materials. Herein, we describe a simple and cost-effective method of replica molding the wing topographies of four cicada species using UV-curable pol...

Background Staphylococcus aureus biofilms pose a unique challenge in healthcare due to their tolerance to a wide range of antimicrobial agents. The high cost and lengthy timeline to develop novel therapeutic agents have pushed researchers to investigate the use of nanomaterials to deliver antibiofilm agents and target biofilm infections more effici...

Biofouling of membranes is an unresolved problem in the water industry. Numerous anti-biofouling membrane technologies have been proposed but the duration of their anti-fouling properties is short relative to the required lifetime of the membrane. The present work investigated a facile renewable anti-biofouling layer strategy whereby smart enzymati...

Wastewater volumes are increasing globally as a result of increased population and industrial growth. This, together with increasingly stringent discharge limits, has resulted in a consequent rise in energy demand for wastewater treatment. Activated sludge process has been successfully used for more than a century with various configurations for th...

The objective of this paper is to determine the importance of integrating peak demand mitigation and future energy pricing structures for process modelling of conventional water resource recovery facilities (WRRFs) when evaluating energy cost and control strategies. The well-established benchmark simulation model (BSM2) is used to monitor energy us...

The efficiency of osmotic backwashing cleaning to remove bacteria from forward osmosis membranes was systematically studied for the first time under different attachment and osmotic backwashing conditions. It is hypothesized that biofouling is preventable when tackling initial adhesion, i.e. during the reversible stage. Cell removal from the membra...

Ammonia is a widely used chemical and its synthesis is an energy intensive process. While the extraction of pure ammonia from nitrogen-rich wastewater streams is not a novel technology, there is potential to examine the process within an energy system framework. Specifically, this paper uses modelling to examine how such a process could be operated...

This study simulates the biogas storage scenarios in medium to large scale wastewater treatment plants (WWTPs) in Ireland, introduces a method to provide energy integration into WWTPs, and compares the impact of different biogas storage scenarios on power system stability, system Time-of-Use electricity prices and the total energy cost of WWTPs. Th...

This study aims to simulate the partial storage of wastewater in the sewer system under dry weather conditions and to analyse the impact of scheduling control on peak energy demand mitigation in a WWTP. Three different flow-shifting scenarios were implemented in the framework of Benchmark Simulation Model No.2 (BSM2) for four separate weeks under d...

The work in this paper focused to discover opportunities to turn biogas produced from sludge into energy source based on a model to maximize the WWTPs’ economical profit in BSM2. In addition, the challenges and issues to apply sludge as an energy source integration with grid have also been evaluated and analyzed.

Biofilms are communities of microorganisms encased in a self-produced matrix constituted of extracellular polymeric substances (EPS). The recalcitrant and often harmful nature of biofilms, particularly in the biomedical field, motivates a search for anti-biofilm compounds and materials. Within this context, nanoparticles (NPs) represent a promising...

Biofilms are microbial communities embedded in an extracellular polymeric matrix and display an enhanced tolerance to the action of antimicrobials. The emergence of novel functionalised nanoparticles is considered a promising avenue for the development of biofilm-specific antimicrobial technologies. However, there is a gap in the understanding of i...

Background Considering the timeline required for the development of novel antimicrobial drugs, increased attention should be given to repurposing old drugs and improving antimicrobial efficacy, particularly for chronic infections associated with biofilms. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA...

The contribution of the biofilm extracellular polymeric substance (EPS) matrix to reduced antimicrobial susceptibility in biofilms is widely recognised. As such, the direct targeting of the EPS matrix is a promising biofilm control strategy that allows for the disruption of the matrix, thereby allowing a subsequent increase in susceptibility to ant...

The commercial use of nanoparticles has increased in recent years due to their unique characteristics, including high surface area, modifiable shape and surface charge and size-dependent properties. Consequently, a greater number of nanomaterials are now being released into the environment and inevitably interact with the natural ecosystem. Bacteri...

Solid waste management has become a global problem as the rate at which waste is generated exceeds population growth. Although it is not the most environment friendly option due to the inevitable generation of greenhouse gases and leachate, landfilling is globally still the most commonly applied waste disposal method. Leachate, an extremely pollute...

Bacterial biofilms are microbial communities in which bacterial cells in sessile state are mechanically and chemically protected against foreign agents, thus enhancing antibiotic resistance. The delivery of active compounds to the inside of biofilms is often hindered due to the existence of the biofilm extracellular polymeric substances (EPS) and t...

A promising tool to achieve more flexibility within power systems is demand response (DR). End users in many strands of industry have been subject to research regarding the opportunities for implementing DR programmes. We review recent DR modelling approaches in the realm of energy systems models and industrial process models. We find that existing...

Combined leachate treatment at municipal wastewater treatment plants (WWTPs) is applicable to a certain extent depending on the leachate composition, treatment plant configuration and its capacity. Co-treatment of leachate at WWTPs has several advantages, but due to increasingly stringent discharge standards applied in WWTPs, it has become more pro...

Biofilms are communities of microorganisms enclosed in a self-generated matrix of extracellular polymeric substances (EPS). While biofilm recalcitrance and persistence are caused by several factors, a reduction in antimicrobial susceptibility has been closely associated with the generation of pH gradients within the biofilm structure. Cells embedde...

The negative consequences of biofilms are widely reported. A defining feature of biofilms is the extracellular matrix, a complex mixture of biomacromolecules, termed EPS, which contributes to reduced antimicrobial susceptibility. EPS targeting is a promising, but underexploited, approach to biofilm control allowing disruption of the matrix and ther...

Demand response (DR) programmes encourage the energy end users to adjust their consumption in accordance to the energy availability and price. Municipal wastewater treatment plants are suitable candidates for the application of such programmes. Demand shedding through aeration control, subjected to maintaining the plant operational limits, could ha...

Continuous processing in the production of peptides is an area of increased interest. In this study, an enzymatic membrane reactor (EMR) was developed whereby whey protein isolate was used as a substrate to prepare DPP-IV inhibitory and radical scavenging peptides via enzymatic hydrolysis. Two separate enzymes were tested: Corolase 2TS and Protamex...

The membrane aerated biofilms reactor (MABR)is an emerging technology in wastewater treatment with particular advantages including high rate nitrification, and very high oxygen transfer efficiencies. In this study a synthetic feed water incorporating tetracycline (TC)was investigated in a MABR. Simultaneous removal of ammonium and tetracycline (TC)...

Most biofilm studies employ single species, yet in nature biofilms exist as mixed cultures, with inevitable effects on growth and development of each species present. To investigate how related species of bacteria interact in biofilms, two Pseudomonas spp., Pseudomonas fluorescens and Pseudomonas putida, were cultured in capillary bioreactors and t...

Difficulties in the removal of bacterial biofilms in the industrial and biomedical sectors have driven the development of new technologies. Although numerous studies have highlighted the use of nanoparticles (NPs) as antibiofilm agents, the fundamental physicochemical interactions between NPs and the biofilm matrix is still poorly understood 1. The...

The use of engineered nanoparticles (NPs) as a technique for antimicrobial delivery aimed at biofilm treatment is an emerging field of research. There have been numerous studies involving a wide range of NPs showing varying results regarding anti-bacterial effects (1). However, research focusing on specific interactions between functionalized nanop...

The surface associated communities of microorganism in biofilms are encased in a matrix of extracellular polymeric substances (EPS). The EPS is made up of mainly polysaccharides, proteins, nucleic acids and lipids and plays an important role in maintaining the integrity of the biofilm (1). Although the general composition of the EPS is known, it ca...

Biofouling is a significant operational impediment in pressure-driven membrane processes. The early stage of biofouling involves bacterial adhesion at the membrane-liquid interface where the physical and chemical conditions are very complex. This study employed a sophisticated model of bacterial adhesion and was combined with a computational fluid...

Attempts to deal with the problem of detrimental biofilms using nanoparticle technologies have generally focussed on exploiting biocidal approaches. However, it is now recognised that biofilm matrix-components may be targets for the disruption or dispersion of biofilms. Here, we show that the functionalization of gold nanoparticles with the enzyme,...

Pharmaceuticals in waterbodies are a growing concern due to their extensive uses and adverse effects on aquatic life. Oxytetracycline (OTC) is one of tetracycline antibiotic group used for treatment of animals and humans. This study evaluates the simultaneous oxidation of OTC and ammonium under autotrophic nitrifying conditions by using a membrane...

The growth of biofilms on surfaces is a complicated process influenced by several environmental factors such as nutrient availability and fluid shear. In this study, combinations of growth conditions were selected for the study of Pseudomonas fluorescens biofilms including as cultivation time (24- or 48 h), nutrient levels (1:1 or 1:10 King B mediu...

Appendix S1. Materials and Methods. Fig. S1. Microbial Fouling Simulator cross flow system experimental rig.

It is now generally accepted that biofouling is inevitable in pressure-driven membrane processes for water purification. A large number of published articles describe the development of novel membranes in an effort to address biofouling in such systems. It is reasonable to assume that such membranes, even those with antimicrobial properties, when a...

In an effort to mitigate biofouling on thin film composite membranes such as nanofiltration and reverse osmosis, a myriad of different surface modification strategies has been published. The use of silver nanoparticles (Ag-NPs) has emerged as being particularly promising. Nevertheless, the stability of these surface modifications is still poorly un...

The performance of pressure-driven membrane filtration processes for water treatment is hampered by biofouling. A relevant, but often overlooked aspect of this phenomenon concerns the localized microenvironment at the membrane interface. A key question is the level of stress on adhering cells and how this impacts on the developing biofilm. In this...

A one-directional modelling method for the assessment of the influence of power ultrasound (US) (4-19 W cm⁻², 25-40min) on NaCl diffusion in pork is presented. In doing so, the mechanistic actions of US salting in meat are elucidated. Temperature controls (4-21 °C) were generated according to each US treatment. NaCl concentration profiles were fitt...

Energy and water have been integrated throughout most of modern history, and that linkage will continue into the future, not only in the physical infrastructure but also through digital infrastructure (e.g., the Internet of Things). The term energy-water nexus is quickly expanding to refer to more than simply water used for energy production and en...

Two polymers, polymethylmethacrylate (PMMA) and cyclic olefin copolymer (COC), containing a range of nano- to micron- roughness surfaces (Ra 0.01, 0.1, 0.4, 1.0, 2.0, 3.2 and 5.0μm) were fabricated using electrical discharge machining (EDM) and replicated using micro injection moulding (μIM). Polymer samples were characterized using optical profilo...

Table S1. FTIR assignments of the analysis of the functionalized Si‐NanoB. Figure S1. A schematized overview of the chemical preparation of enzyme functionalized silica nanobeads. Figure S2. FTIR spectra of functionalized (Silica+PK) and non‐functionalized (Si‐NanoB) nanobeads Figure S3. Representative SEM micrographs of Si‐NanoB (a‐b) and Si‐Na...

A good understanding of the mechanical stability of biofilms is essential for biofouling management, particularly when mechanical forces are used. Previous biofilm studies lack a damage-based theoretical model to describe the biofilm separation from a surface. The purpose of the current study was to investigate the interfacial separation of a matur...

Recently, the surface of the wings of the Psaltoda claripennis cicada species has been shown to possess bactericidal properties and it has been suggested that the nanostructure present on the wings was responsible for the bacterial death. We have studied the surface-based nanostructure and bactericidal activity of the wings of three different cicad...

The amelioration of biofouling in industrial processing equipment is critical for performance and reliability. While conventional biocides are effective in biofouling control, they are potentially hazardous to the environment and in some cases corrosive to materials. Enzymatic approaches have been shown to be effective and can overcome the disadvan...

The amelioration of biofouling in industrial processing equipment is critical for performance and reliability. While conventional biocides are effective in biofouling control, they are potentially hazardous to the environment and in some cases corrosive to materials. Enzymatic approaches have been shown to be effective and can overcome the disadvan...

A fundamental understanding of biofilm mechanical stability is critical in order to describe detachment and develop biofouling control strategies. It is thus important to characterise the elastic deformation and flow behaviour of the biofilm under different modes of applied force. In this study, the mechanical properties of a mature wastewater biof...

High Cell Density (HCD) cultivation of bacteria is essential for the majority of industrial processes to achieve high volumetric productivity (g L-1 h-1) of a bioproduct of interest. This study developed a fed batch bioprocess using glucose as sole carbon and energy source for the HCD of the well described biocatalyst P. putida KT2440 without the s...

Cunninghamella elegans is a fungus that has been used extensively as a microbial model of mammalian drug metabolism, whilst its potential as a biocatalyst for the preparative production of human drug metabolites has been often proposed, little effort has been made to enable this. Here, we describe a workflow for the application of C. elegans for th...

In the context of biofilm development, detachment is of practical importance when placed in a biofilm management perspective. The objective of the present study was to examine biofilm structure and biofilm detachment under controlled conditions for two distinct microorganisms grown under constant shear conditions. Detached biofilm biomass was regul...

Organic conditioning films have been shown to alter properties of surfaces, such as hydrophobicity and surface free energy. Furthermore, initial bacterial adhesion has been shown to depend on the conditioning film surface properties as opposed to the properties of the virgin surface. For the particular case of nanofiltration membranes under permeat...

The influence of permeate flux on bacterial adhesion to NF and RO membranes was examined using two model Pseudomonas species, namely Pseudomonas fluorescens and Pseudomonas putida. To better understand the initial biofouling profile during NF/RO processes, deposition experiments were conducted in cross flow under permeate flux varying from 0.5 up t...

It is imperative that nanofiltration membranes are disinfected before they are used for laboratory-scale bacterial adhesion or biofouling experiments, yet currently no suitable disinfection protocol exists. This study aimed to determine if an ethanol treatment at a minimum inhibitory concentration (MIC) could be used to effectively disinfect nanofi...

A mathematically based fed-batch bioprocess demonstrated the suitability of using a relatively cheap and renewable substrate (butyric acid) for Pseudomonas putida CA-3 high cell density cultivation. Butyric acid fine-tuned addition is critical to extend the fermentation run and avoid oxygen consumption while maximising the biomass volumetric produc...

Nanofiltration (NF) is a high pressure membrane filtration process increasingly applied in drinking water treatment and water reuse processes. NF typically rejects divalent salts, organic matter and micropollutants. However, the efficiency of NF is adversely affected by membrane biofouling, during which microorganisms adhere to the membrane and pro...

Diverse and elaborate pathways for nutrient utilization, as well as mechanisms to deal with unfavourable nutrient conditions make Pseudomonas putida KT2440 a versatile microorganism able to occupy a range of ecological niches. P. putida's fatty acid degradation pathway is complex and correlated with biopolymer medium chain length polyhydroxyalkanoa...

A method of assessing biofilm thickness in a membrane supported biofilm reactor (MSBR) of the type comprising a lumen containing a gas phase, a liquid phase, and a gas permeable membrane providing an interface between the gas and liquid phases, the method comprising the steps of charging the lumen with an inert gas, closing the lumen to establish a...

The purpose of this study was to investigate the feasibility of cultivating the biotechnologically important bacterium Streptomyces griseus in single-species and mixed- species biofilms using a Tubular Biofilm Reactor (TBR). Streptomyces griseus biofilm development was found to be cyclical, starting with the initial adhesion and subsequent developm...

A process for the conversion of post consumer (agricultural) polyethylene (PE) waste to the biodegradable polymer medium chain length polyhydroxyalkanoate (mcl-PHA) is reported here. The thermal treatment of PE in the absence of air (pyrolysis) generated a complex mixture of low molecular weight paraffins with carbon chain lengths from C8 to C32 (P...

Phenol can be oxidized to the end products when oxygen is used as an electron acceptor. This study evaluated phenol oxidation in an oxygen‐based membrane biofilm reactor (MBfR). The system achieved highest oxidation of both phenol and glucose when the phenol loading and glucose loading was ∼4.7 and ∼55 g m−2 day−1, respectively. These conditions we...