Chemical Engineering

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This is the collection for the University of Waterloo's Department of Chemical Engineering.

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Analysis of Heterogeneities in a 20 L Bioreactor
(University of Waterloo, 2025-10-02) Kang, Danny
Biological systems are utilized in various industries to produce valuable products, including biopharmaceuticals. This is done in bioreactors, which are specialized vessels that are able to precisely control key parameters, including agitation, air flow, temperature, pH, dissolved oxygen, and nutrient supply. With the high demands for biopharmaceuticals caused by advancements in medicine, the need for efficient production and optimization of bioreactors has been evident. This has been especially seen during the COVID-19 pandemic, and the high costs of some products, which are inaccessible to many individuals. To optimize production, simulation models have been developed to predict effective control schemes for high growth and product yield. However, this is challenging to translate between lab-scale and industrial-scale due to the formation of gradients in industrial-scale systems, which have poor mixing. Gradients lower the efficiency of bioreactors as cells must constantly adapt to changing extracellular conditions, which cause stress and lower yields. Thus, it is necessary to validate simulation models using the gradients formed in large-scale bioreactors; however, this data is not readily available, and it is difficult to obtain such gradients in smaller-scale bioreactors. In this work, fed-batch experiments are studied to investigate the formation of gradients in dissolved oxygen, kLa, pH, cell density, glucose, and acetate concentrations. This was done through the movement of sensors, turning the air on and off, and the usage of different sampling locations. The objectives of this work were first to characterize the culture with flask and batch experiments and then to use this information to carry out the fed-batch experiments to explore the potential of measuring these gradients. Dynamic metabolic responses were observed and measured depending on the control of the glucose feeding, and consistent gradients were observed for the dissolved oxygen, pH, and kLa, while gradients for cell density, glucose, and acetate were not observed, which may be due to limitations in sampling times. Finally, the metabolic responses have been modeled using modified Monod kinetics, where the modifications include self-growth inhibition, an acetate metabolic switch, and a cell density-dependent lag function. This work was done using a genetic algorithm on Python to optimize parameters, and the model was able to adapt to the different extracellular conditions presented in the fed-batch experiments.
Defining and Validating Convergence Criteria for the Determination of Representative Elementary Volume in Porous Media
(University of Waterloo, 2025-09-23) Fan, Ricky
The representative elementary volume (REV) is a fundamental concept in the study of porous media, describing the minimum volume at which a material property can be considered statistically representative of the whole. Determining an REV is essential for linking pore-scale measurements, often obtained from high-resolution imaging, to continuum-scale models used in engineering and geoscience. In particular, accurate REV identification of porosity and tortuosity is critical, as these parameters govern transport processes such as flow, diffusion, and conductivity in porous structures. This work presents a systematic methodology for identifying REVs based on a threshold criteria designed to reduce computational demands. An REV is defined as the volume in which at least 80% of 100 randomly sampled subdomains yield porosity or tortuosity values within 20% of the overall average. The method was applied to both synthetic datasets and real samples provided by Dong and Blunt, with subdomain volumes ranging from 10^3 to 100^3 voxels [1]. Of the 12 real samples analyzed, 7 satisfied the proposed criteria, and REVs were identified for both porosity and tortuosity. Samples that met the criteria exhibited smaller average pore sizes and higher porosity ratios, while outliers were explained using pore size distribution data. To further assess robustness, predicted tortuosity values obtained using the correlation proposed by Tomadakis and Sotirchos were compared with ground truth measurements [2]. Several samples failed to reproduce the true values, indicating that even when an image contains an REV, it may not be internally self-consistent. While this may appear contradictory, it reflects the distinction between the stability of averaged values across subdomains and predictive accuracy of empirical correlations. The results of this work demonstrate that REVs can be identified from relatively small fractions of the total image volume given that certain conditions are met, offering a balance between accuracy and computational efficiency. This framework provides a flexible approach for porous media characterization, with direct implications for hydrogeology, petroleum recovery, fuel cell design, and filtration technologies.
3D printable fungi-based Chitin nanofiber/CNC hydrogels: implication for fabrication of functional cryogels
(University of Waterloo, 2025-09-15) Ghasemi, Shayan
Fungal-derived chitin nanofibers represent a naturally abundant and renewable material with considerable mechanical strength, making them a promising candidate for advanced material applications. However, their application in 3D printing remains in the early stages of research, as pure fungal chitin hydrogels exhibit poor printability that limits their use in additive manufacturing. In our study, we address this challenge by incorporating cellulose nanocrystals (CNCs) into the chitin-based hydrogels. The addition of CNCs effectively fine-tunes the rheological properties of the chitin-based hydrogels, enabling stable extrusion-based 3D printing while preserving the structural integrity of the material. This approach allowed us to formulate a range of high-fidelity printing inks by hybridizing these bio-based nanomaterials, ultimately creating sustainable aerogels that are ideal for divers applications. Moreover, while CNC aerogels often suffer from insufficient mechanical strength and poor handling characteristics, hybridizing them with chitin nanofibers results in robust, well-structured aerogels. Compression tests confirmed that the mechanical strength of these aerogels is predominantly dictated by chitin network, with CNCs contributing significantly to improved printability and enhanced structural uniformity. To further expand the functional properties of these hybrid aerogels, we incorporated multi-wall carbon nanotubes (MWCNTs) to impart electrical conductivity, thereby enabling their use in electromagnetic interference (EMI) shielding applications. Electrical conductivity measurements demonstrated excellent charge transport capabilities, resulting in a total EMI shielding effectiveness of 34 dB over the X-band frequency range (8–12 GHz). Overall, this study highlights the tremendous potential of fungal-derived, 3D printable chitin aerogels as sustainable, lightweight substrates, offering an eco-friendly alternative to conventional synthetic composites for applications ranging from wound dressings to EMI shielding devices.
Kraft Lignin as a Sustainable Flame Retardant Additive for Polymer Composites
(University of Waterloo, 2025-09-11) Alikiotis, Periklis Dimitrios
Plastic waste is a widespread and continuing issue, including the leaching of toxic additives from microplastics. Lignin is the second most abundant biopolymer, and although previously considered as waste and used as fuel, lignin’s availability and unique properties have garnered popularity as a sustainable and functional additive in many material applications. In this thesis, the versatility of lignin is explored at varying levels of valorization. The first part of this work explored three differing purities of lignin and their effect on the properties of polyvinyl chloride (PVC) composites. These were tested alongside composites with differing concentrations of lignin and were all subject to various thermomechanical and flammability testing. Additionally, the decomposition kinetics of PVC and a lignin-PVC composite were explored. The industrially purified lignin outperformed the other purities mainly in mechanical properties, but the laboratory purified lignin retained the most heat capacity compared to the control. Additionally, at a concentration of 18 wt.% lignin, combustion indices were improved by 50 to 80%, but the elongation at break of these composites were reduced by 38.7%. The second part of this work focused on incorporating a hydrophilic FR (ammonium polyphosphate) into natural rubber (NR), a hydrophobic polymer, by utilizing nano-containers constructed via the crosslinking of lignin. The properties of the lignin nanocontainers (LNCs) were studied to best enhance the dispersion of this filler within the NR at varying concentrations. These composites were tested alongside bulk incorporated lignin & FR as well as foamed samples to best determine the value brought by the LNCs. At a concentration of just 10 wt.% LNC, various flammability parameters improved and outperformed the bulk incorporated sample. This work demonstrated the versatility of lignin to by adding value to polymeric materials without additional modification or being modified to improve its incorporation as a nanomaterial.
Designing Porous Polymer Systems for Water Treatment Applications
(University of Waterloo, 2025-09-11) Crawford, Ethan
Increasing pollution and contamination of the World’s water bodies come with great concern over potable water safety and accessibility. Current solutions for water treatment often have large carbon footprints or are too expensive to scale up effectively. These shortcomings warrant the exploration of new and effective methods of water treatment. Polymer-based solutions offer lightweight, scalable, and inexpensive methods for water filtration while being minimally intrusive to the surrounding environment. In particular, porous polymeric materials have garnered considerable attention due to their high specific surface area, which enables them to have enhanced interactions with their target analyte. This thesis presents two such types of porous materials: nonwoven fabrics and three-dimensional (3D) printed filters. The first section of this thesis focuses on nonwovens, a type of fabric comprised of bonded, interlocking, randomly oriented fibers. Nonwovens can be used as topically placed sorptive mats for the removal of pollutants, or as a pass-through filter for the separation of water from the pollutants. Here, the unique oil gelation properties styrene-ethylene-butylene-styrene (SEBS) block copolymer are leveraged for the creation of melt-blown nonwovens for oil-water separation applications. The poor processability of SEBS, due to its elastomeric nature, was overcome through highly optimized processing parameters to create fine diameter, highly porous nonwoven mats. These mats possessed exceptional lipophilicity and oil-water separation properties due to the oil-soluble midblocks of SEBS that created a semi-solid gel capable of retaining all oil it came into contact with. The latter section of this thesis focuses on 3D printing, specifically fused deposition modelling (FDM), for the creation of flow-through filters for microplastic capture. 3D-printed parts are often very smooth, greatly limiting their surface area and ability for microplastics to become lodged on their surface. To overcome this, a sacrificial additive was added to the base polymer matrix that could be etched out, creating a highly porous surface that greatly improved the filtration efficiency of the printed filters. Pressure-sensitive adhesives (PSAs) were also explored and were found to further bolster the filtration capabilities of the filters. This is due to the added tack and non-covalent interactions that more strongly hold microplastics to the surface of the filters. The findings from these studies demonstrate a promising direction for utilizing porous polymer systems in water treatment applications.
Dry Extraction of Nickel from Mixed-Hydroxide Precipitates via Reduction and Carbonylation
(University of Waterloo, 2025-09-09) Dave, Param
The global transition towards electric vehicles (EVs) has prompted significant research into the sustainable and efficient production of battery-grade materials. Among the critical components of rechargeable batteries, nickel (Ni) is of particular importance due to its central role in cathode materials, specifically for Nickel Manganese Cobalt (NMC) and Nickel Cobalt Aluminum (NCA) batteries. Ni is conventionally extracted from primary sources such as laterite ores (containing 2-3% Ni by mass) through hydrometallurgy (with acid-intensive processing) or pyrometallurgy (with high-temperature, energy-intensive processing). Hydrometallurgical extraction produces an intermediate product called mixed-hydroxide precipitate (MHP), which can contain up to 50% Ni by mass on a dry basis, but still requires further processing to obtain high-purity nickel. This study explores an alternative, sustainable and selective extraction pathway for nickel from MHPs derived from laterite ores and spent battery materials (black mass). The explored vapour metallurgical approach is a two-step, dry process: 1) hydrogen reduction of nickel hydroxides with the MHP to metallic nickel at temperatures between 400°C to 500°C, and 2) selective nickel extraction via carbonylation and conditions of 100°C to 120°C and 150 psig to 450 psig. The carbonylation of metallic Ni using carbon monoxide (CO) produces a volatile molecule called nickel tetracarbonyl (Ni(CO)4), which selectively extracts Ni into the vapour phase. Rigorous safety protocols were employed in this research study to handle the toxic nature of the produced Ni(CO)4 molecules, including CO detectors to identify leaks, and an in-situ decomposition furnace downstream of the reactor to thermally decompose the carbonyls. Reduction and subsequent carbonylation experiments were conducted in a pressurized thermogravimetric analyzer (PTGA), allowing for real-time monitoring of mass changes associated with the reactions. Characterization techniques, including Fourier Transform Infrared (FTIR) spectroscopy, inductively coupled plasma–optical emission spectroscopy (ICP-OES), and Brunauer-Emmett-Teller (BET) analysis, were used to quantify Ni extraction, evaluate morphological changes from fresh samples to reaction residue, and confirm the formation of Ni(CO)4. Significant results demonstrated that the Ni extraction via carbonylation is strongly dependent on the precursor’s structural properties, specifically requiring high surface areas, adequate pore sizes, and minimal cobalt content to enhance transport of CO and Ni(CO)4. Optimal reduction conditions were identified at 450°C, producing residues with a balanced surface area and average pore size, favourable for the carbonylation reaction. Increased carbonylation pressure, at 450 psig, improved Ni extraction efficiency to 95% for a black mass-based MHP.
Nanocellulose from Hemp: Characterization for Molded Pulp Applications
(University of Waterloo, 2025-09-09) Abdul Hadi Bin Jawad, .
The global shift to sustainable packaging solutions has generated growing attention towards biodegradable substitutes for traditional plastic materials. Molded pulp products, originating from lignocellulosic fibers, are both biodegradable and recyclable; however, they frequently demonstrate inadequate mechanical strength and moisture resistance, which restricts their use in high-performance packaging applications. This study explores the capabilities of cellulose nanofibers (CNF) as a reinforcing additive to enhance the characteristics of molded pulp. CNF was generated from multiple hemp-derived sources through Masuko grinding at varying pass levels and characterized using centrifugation-based techniques, such as water retention value (WRV) and settling volume, to assess their degree of fibrillation and dispersion. TEM analysis validated the findings from the centrifugation-based techniques, confirming that the trends noted in settling volume and WRV correspond to fibrillation quality at the nanoscale. Among the samples evaluated, Dry Anka Bast processed at 12 passes exhibited exceptional dispersion characteristics and was chosen for further application. CNF was integrated into molded pulp of four types: softwood, hardwood, thermo-mechanical eucalyptus pulp (TMP), and kraft eucalyptus pulp. Mechanical testing was performed to evaluate the impact of CNF incorporation on tensile strength and structural integrity. The findings indicated that CNF markedly improved the mechanical properties of molded pulp, especially in both softwood and hardwood samples, where there was a notable increase in tensile strength. Tensile strength increased from 4 MPa to 13 MPa in hardwood pulp, from 4 MPa to 18 Mpa in softwood pulp, from 3 MPa to 14 MPa in Kraft Eucalyptus pulp, and from 1 MPa to 3 MPa in TMP Eucalypts. The findings validate the enhancing capabilities of CNF and emphasize the significance of the CNF source and processing conditions in maximizing the performance of molded pulp. The results of this study contribute to the development of efficient, bio-based packaging solutions and support wider initiatives aimed at minimizing plastic waste via sustainable material innovation.
Interfacial Behaviors of Polymer and Metal-Polymer Thin Films under Contact and Solvent Stimuli
(University of Waterloo, 2025-09-04) Fan, Zhao
Polymeric thin films and metal-polymer bilayers are foundational components in flexible electronics, adaptive surfaces, and emerging interface technologies, valued for their mechanical compliance, ease of processing, and tunable functionality. Unlike homogeneous rigid or bulk elastic materials, polymer thin films exhibit inherently display scale-dependent mechanical and optical properties, particularly at interfaces, where deformation behavior is governed by factors such as film thickness, cross-link density, and free liquid content, often resulting in nonlinear and time-dependent viscoelastic phenomena. The integration of nanoscale metallic coatings introduces an additional layer of complexity: the rigid-soft coupling further alters both mechanical and optical properties, giving rise to hybrid contact behaviors that go beyond the assumptions of classical contact theories developed for either purely stiff or bulk soft materials. Moreover, the interfacial deformations are typically confined to micro- or even nanometer scales, where stress localization, modulus gradients, and geometric confinement jointly govern the contact behaviors and its evolution. This multiscale, multiphysics coupling presents significant challenges for experimental characterization. Most conventional techniques isolate mechanical and optical measurements, rely on model-specific assumptions, and involve multi-step or complicated procedures. Thus, these techniques present certain challenges in precisely characterizing the real micro-scale structural properties and deformation behavior under actual loading or environmental conditions. Despite growing interest in these bilayer systems, a clear, experimentally accessible framework for quantitatively probing their contact behaviors and underlying properties remains lacking. Addressing this gap is essential not only for advancing the fundamental understanding of thin film mechanics, but also for enabling the rational design of high performance, multifunctional soft interfaces for next generation technologies. To address this gap, this dissertation applies spectroscopy and microscopy techniques: confocal Raman spectroscopy and dual-wavelength reflection interference contrast microscopy (DW-RICM), to systematically investigate the interfacial behaviors of polymeric and metal-polymer bilayer thin films under contact and solvent stimuli. The resulting insights aim to inform the rational design of multifunctional soft interfaces with enhanced performance and broader applicability in next generation surface and device technologies. The dissertation first highlights a parameter independent framework for characterizing soft contact deformation using in-situ confocal Raman spectroscopy. To achieve this, a calibration platform was constructed using a five-glass sphere probe assembly, with a glass slide placed on top to establish a reliable measurement protocol. This setup was then adapted for soft contact analysis by replacing the upper glass slide with a PDMS coated glass slide (P10), enabling localized deformation under controlled spherical contact. Raman mapping was performed in three spatial dimensions by tracking the intensity distribution of the 2905 cm⁻¹ Raman peak, which serves as the -CH3 stretching of PDMS. The resulting contour maps enabled imaging of the deformation region across multiple planes, allowing the extraction of physical parameters such as contact radius and indentation depth. The obtained results were broadly consistent with Hertz predictions, while revealing local deviations indicative of non-conformal contact behavior. The proposed technique and framework offers a unique method to observe the formation and change of contact deformation, leading to a deeper insight into the soft contact system. Building upon this molecular insight, a methodology was developed to simultaneously extract the optical and mechanical properties of polymer and metal-polymer bilayer thin films using dual-wavelength reflection interference contrast microscopy (DW-RICM). Nanoscale gold (Au) and silver (Ag) layers were deposited on PDMS substrates with varying elasticity and coating thickness. By analyzing interference patterns obtained at two wavelengths (488 nm and 561 nm) during contact with a glass probe of known geometry, the effective refractive indices and elastic modulus of the bilayer system were quantitatively determined. The refractive index was found to decrease with increasing metal deposition time, decreasing PDMS elasticity and increasing coating thickness, consistent with UV/Vis spectroscopy measurement. Elastic moduli were derived using Hertz theory based on the measured contact radii. This integrated optical-mechanical approach simplifies current multi-step characterization procedures, offering insights into fundamental properties of the metal-polymer bilayers. To further investigate the metal thin layer coating on the contact behavior of metal-polymer bilayers, a black-ink-coated probe was incorporated with DW-RICM to suppress unwanted reflections at the probe-air interface. This modified configuration enabled visualization of deformation features including contact deformation region and contact ridge formation with nanoscale resolution. Experimental results show that increasing the metal deposition time (i.e., metal coating thickness) leads to a reduction in both contact radius and contact ridge height. Moreover, long-term contact analysis of the gold coated bilayers showed a steady increase in ridge height over time, unlike the gradual decrease observed in the bare counterparts until reaching a steady state, suggesting altered interfacial viscoelastic behavior driven by the presence of the metal coating layer. Building on insights into the role of free liquids in thin film contact behavior, the final phase of this dissertation investigates out-of-equilibrium interfacial mechanic of solvent-induced surface instabilities on solid supported soft substrates using DW-RICM. The morphological evolution of PDMS and silicone gel substrates were monitored over prolonged hexane extraction and drying. A consistent transition was observed from shallow circular depressions to highly ordered triradial (Y-shaped) surface patterns driven by internal stress accumulation and elastic modulus gradients between the surface and bulk. Comparative analysis across formulations with varying crosslinking densities revealed that while the pattern formation mechanism is broadly conserved, it remains sensitive to material properties such as free liquid content and elasticity. These findings shed light on the mechanisms of solvent-mediated patterning and underscore solvent processing as a promising strategy for engineering programmable surface architectures in soft materials. Overall, this dissertation constructs a framework for soft interface characterization, integrating mechanical deformation under contact and surface morphological transformation under solvent extraction. The findings highlight how vibrational spectroscopy and optical interferometry can be used in tandem to probe complex contact phenomena, offering new tools and insights for the design of adaptive, compliant surfaces in applications such as soft robotics, flexible electronics, and interfacial patterning.
Facile SEI Improvement in the Artificial Graphite/LFP Li-ion System: via NaPF6 and KPF6 Electrolyte Additives
(University of Waterloo, 2025-09-03) Rahbariasl, Sepehr
Lithium-ion batteries (LIBs) are the most widely used energy storage technologies for grid-scale applications, electric cars, and portable devices because of their consistent voltage profiles, high energy density, and extended cycle life. However, interfacial degradation events, especially at the anode, frequently restrict their long-term performance. The creation of the solid electrolyte interphase (SEI) layer, a passivation film that occurs on the graphite anode surface during the initial cycles, is one of the most important issues in this context. Increased impedance, irreversible capacity loss, and decreased coulombic efficiency are caused by unstable or excessive SEI production, which is necessary for stabilizing the electrode–electrolyte interface. These issues are made worse by fast charging or prolonged cycling. This thesis uses artificial graphite anodes and lithium iron phosphate (LFP) cathodes to examine the effects of sodium hexafluorophosphate (NaPF₆) and potassium hexafluorophosphate (KPF₆) additives on SEI properties and electrochemical performance in LIBs. These alkali salt additives, which are rarely investigated in lithium-ion systems, are being investigated as scalable and affordable substitutes for traditional SEI-modifying additives. The effects of the additives were evaluated by electrochemical testing, which included galvanostatic cycling, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), as well as surface and structural characterization (SEM and XPS). According to our results, using KPF₆ and NaPF₆ considerably lowers irreversible capacity loss (by 38.98% and 37.85%, respectively) as compared to a baseline LiPF₆ electrolyte. Additionally, full cell tests show enhanced capacity retention without adversely altering ionic conductivity, with 67.39% for NaPF₆ and 30.43% for KPF₆ across 20 cycles. High-conductivity electrodes used for SEI generation at 1C further validated the additives' capacity to continue functioning during faster formation. These results provide new perspectives on mixed-ion SEI engineering and show how promising NaPF₆ and KPF₆ are for improving LIB performance in demanding applications like electric vehicles.
Chitosan/SIFSIX-3-Cu Cryogels on Printed Laser-Induced Graphene for CO2 Electric Swing Capture
(University of Waterloo, 2025-08-26) Ho, Monica
To achieve global net zero greenhouse gas emissions, carbon dioxide (CO2) removal technologies (CDR) must be deployed at gigatonne scale by the end of the decade. Direct air capture (DAC) is one category of CDR technology which shows promise due to its more straightforward measurability and verifiability. Low temperature, solid sorbent-based DAC systems in particular offer a lower energy demand and when paired with renewable electrical systems, avoid the use of fossil fuels and the generation of additional CO2 emissions in the process. Several sorbents have been investigated for electric swing adsorption (ESA) DAC, where heat generated using the Joule heating principle is used for the desorption of CO2 from the sorbent. Most of the sorbents are carbonaceous due to their semi-conductive nature which allows for electrical current travel. However, these sorbents suffer from reduced capacity at low CO2 partial pressures, making them less suitable for DAC. As an alternative, we explore an indirect ESA process using laser-induced graphene (LIG) which acts as a flexible heater layer. For the adsorbent layer, chitosan (CS) cryogel with in situ synthesized SIFSIX-3-Cu metal organic framework (MOF) is fabricated for its high capacity, appreciable CO2 selectivity, and sustainability. The pure MOF powder reached its maximum adsorption capacity of approximately 2.5 mmol g⁻¹ within just five minutes, demonstrating its exceptionally fast adsorption kinetics. In contrast, the pure chitosan (CS) cryogel required more than 30 minutes to reach the same capacity. The CS/MOF hybrid cryogel exhibited intermediate kinetics, achieving a maximum adsorption capacity of 2.92 mmol g⁻¹. It was shown that the adsorbents could be regenerated in temperature range of 70-80°C, had low N2 uptake, and 88% of the CS/MOF cryogel capacity was maintained after 4 cycles. Patterned LIG grids were subsequently fabricated and could raise the temperature of the CS/MOF cryogel adsorbent via Joule heating to the target regeneration temperature in 66 s with only 15 V. The LIG grid could also consistently generate the desired temperature range over 4 cycles. Lastly, the chitosan cryogel was fabricated directly on a LIG grid without compromising its heating capability. This successfully demonstrates how an environmentally conscious and efficient ESA system can be engineered by combining LIG optimized for heating and eco-friendly adsorbents with high CO2 capacity.
A CRISPR-Cas9 and next-generation sequencing approach for late/very late AcMNPV gene disruption and comprehensive mutation analysis
(University of Waterloo, 2025-08-26) Chakraborty, Madhuja
The recent global pandemic COVID-19 has taught us the importance of an efficient biologics manufacturing platform that is cost-effective, reliable, and has high product yield and quality. The baculovirus expression vector system (BEVS) has proven to be a promising platform for the production of recombinant proteins, vaccines, virus-like particles (VLPs), viral vectors, and/or other biologics. In the last two decades, many vaccines and therapeutics manufactured using BEVS have received licenses for animal and human use. The majority of the commercially available BEVS transfer plasmids have foreign genes under the viral polyhedrin (polh) or p10 promoters. Although high gene expression can be achieved with the endogenous baculovirus promoters p10 and polh, they are only active very late in the infection cycle when most of the host cellular machinery is turned off. Significant work has been done to identify native promoters and other regulatory elements with expression profiles higher than polh, as well as promoters weaker than polh to express secretory proteins that require extensive post-translational modifications (PTMs). Certain regions, such as polh, chiA, and v-cath, in the baculovirus genome are not essential for their in vitro replication or foreign protein production in cell culture. Thus, it is possible that if there is an expression of genes not required for progeny virus and/or exogenous protein production in insect cell culture, the resources that are being used for their expression could be ‘an additional burden’, resulting in unnecessary depletion of cellular resources. Identifying and removing these genes would probably divert resources towards the production of foreign proteins and progeny viruses, which could improve the BEVS production platform. Moreover, it was previously demonstrated that there is a ‘competition effect’ among protein-coding genes for cellular resources when Sf9 cells are either coinfected with two monocistronic recombinant baculovirus expression vectors (rBEVs) or infected with a dual-protein producing polycistronic rBEV. This work could point to a direction where competition can arise among baculovirus genes for the use of cellular resources, and the knockout of unnecessary genes could presumably lead to appropriate usage of the resources by the essential genes. Separately, the co-production of rBEVs and recombinant protein products in the supernatant complicates the downstream purification process. Disruption of genes essential for virion formation or production could prevent baculovirus contamination in the culture supernatant, thus reducing the burden on purification processes. In the past, gene disruption or downregulation has been a fruitful strategy to improve the expression of foreign genes in the BEVS. However, the traditional methods used for mutant baculovirus genome generation are time-consuming, labor-intensive, and sometimes also produce wild-type viruses, hence requiring additional purification steps. Not until recently has CRISPR-Cas9 gene editing technology been adapted to the Sf9 insect cells and the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV). It is believed to be an effective tool to scrutinize baculovirus genes by targeted gene disruption and transcription repression. A systematic study of the late and very late AcMNPV genes using a CRISPR-Cas9-based transfection-infection assay (T-I assay), disrupting the unnecessary sequences, and expressing exogenous gene(s) under a late promoter instead of very late promoters could extend the production time and improve biologics production. Moreover, in the final production stage, targeting AcMNPV genes that are required for progeny virus assembly or release but do not affect foreign protein production could minimize rBEV co-production. In this study, the T-I assay was used to probe late and very late AcMNPV genes for their essentiality. Based on the effect of individual gene disruptions on foreign protein (green fluorescent protein (GFP)) and budded virus (BV) production, 38 targeted AcMNPV genes were categorized as essential (reduced both GFP and BV production) and of special interest (reduced GFP production but did not lower BV production). While we identified 19 AcMNPV genes that are essential for BV production and GFP expression from the late p6.9 promoter, 19 other genes were identified as of special interest whose disruption only reduced GFP expression from the late p6.9 promoter. While phenotypic changes were assessed using the CRISPR-Cas9-based T-I assay, investigating the genomes using whole-genome next-generation sequencing (NGS) revealed further information. First of all, shotgun sequencing was used to generate a consensus sequence of the p6.9GFP rBEV stock used in T-I assays, and this is the first report on whole-genome rBEV sequences to the best of our knowledge. This shotgun-sequenced rBEV served as the reference genome to identify mutations upon CRISPR-Cas9-mediated gene disruptions. We also provided a set of tiled-amplicon primers based on the reference genome and adapted a high-throughput tiled-amplicon sequencing assay to control and targeted rBEV genomes. This sequencing assay, combined with a bioinformatics pipeline for major species, was able to successfully detect mutations within the gp64 gene when gp64 targeting sgRNA was delivered to Sf9-Cas9 cells via a plasmid or rBEV. We further demonstrated that gp64 disruption lowered BV levels without decreasing GFP production, thus reducing BV contamination in cell culture supernatant. To probe the gp64 gene further, we targeted it at six different locations using the T-I assay. Plasmids carrying one or two sgRNA targets were used to evaluate the impact of single and multiple targeting sites on virion and foreign protein production. gp64 disruption with each of these sgRNA targets resulted in decreased infectious and total viral titers, whereas GFP production from the late p6.9 promoter was enhanced or remained similar to the control. Low-frequency genomic changes upon CRISPR-Cas9-mediated gp64 disruptions were successfully assessed by the tiled-amplicon sequencing assay and a variant calling pipeline based on the computational tool iVar. While the iVar tool was originally developed to investigate variants in wild-type virus populations, we adapted it to detect variants in a process system. We also demonstrated that variants can be preserved over viral propagation in cell culture, that is, variants present in the virus stock were also observed in the rBEV genomes recovered from the T-I assay, thus indicating that they are not detrimental to viral fitness.
Analysis of integrated heating approaches for cold-start conditions in 21700 lithium-ion battery modules using thermal system simulation
(University of Waterloo, 2025-08-25) Parra Panchi, Grace Stephanie
Cold ambient conditions significantly reduce discharge capacity and slow the thermal response of lithium-ion cells, particularly at low state of charge (SOC). To address these challenges, this research studies the feasibility of heating strategies to improve cold-start performance in 21700 lithium-ion battery modules using thermal system simulation. Both experimental and simulation-based approaches were employed. At the cell level, experimental tests were conducted to evaluate thermal and capacity behavior under sub-zero temperatures. These results were compared against thermal system simulation simulations under convective or adiabatic conditions, revealing that experimental test setups introduce additional resistances not captured in idealized models. And adiabatic conditions could allow faster cell heating compared to convective conditions due to internal heat accumulation, which shows the effect of insulation. In fact, the temperature rise simulated under adiabatic conditions is approximately 2.3 to 2.9 times greater than under simulated convective conditions. Building on these findings, a module design was developed to enable system-level simulation of thermal strategies. The design considered safety, structural integrity, and thermal performance, balancing insulation with heat flow pathways. Then the study focuses on evaluating the feasibility of external and battery-powered heating strategies. Four heating configurations were simulated, external heating, battery discharge, or combined configurations. Simulations were carried out across below zero ambient temperatures of -20 °C, -10 °C, and 0 °C and different initial SOC values of 80%, 50% and 20%. Results show that in the absence of heating, the battery was unable to complete discharge at low SOC, particularly at -20 °C and 20% initial SOC. Yet when external surface heating was applied, the module achieved a faster temperature rise enabling full discharge even under these extreme conditions. Furthermore, when external heating is applied without discharge, the heating rate slows down, highlighting the added benefit of internal heat generation during battery operation. Lastly, the study evaluated whether the battery could power its own heating system. At 20% SOC and -20 °C, the energy required for heating exceeded the battery’s usable output, rendering self-heating unfeasible. In contrast, at 0 °C and moderate SOC levels, it remained viable, with heating demands as low as 2 to 3% of the available capacity. Overall, the findings support the integration of targeted heating strategies into electric vehicle (EV) thermal management systems, showing that a combination of external heating and internal heat generation enables reliable cold-start performance while minimizing energy consumption for battery heating in sub-zero conditions.
Design and Assessment of Membrane-supported Ammonia Cracking for Hydrogen Refuelling Stations
(University of Waterloo, 2025-08-25) Smyth, Emily
As Canada aims to reduce greenhouse gas emissions, there is a growing shift toward cleaner energy and fuel sources. Hydrogen has emerged as a promising alternative fuel source due to its high gravimetric energy density and ability to power fuel cell electric vehicles without producing direct carbon dioxide emissions. However, there are currently challenges in storing and transporting large amounts of hydrogen. Ammonia is gaining attention as a hydrogen carrier because it can be stored under moderate pressure or refrigeration and leverages existing infrastructure. Once delivered, hydrogen can be extracted from ammonia through on-site decomposition and purification. Although this pathway shows promise, its competitiveness depends on the system's energy requirements, operating costs and emissions. Furthermore, most existing ammonia decomposition and hydrogen refuelling models are proprietary, limiting accessibility for researchers and small-scale developers. This thesis addresses this gap by developing an open-source process model for a palladium membrane supported ammonia decomposition process at hydrogen refuelling stations. The process delivers 500 kg of hydrogen gas at 350 bar per day, and its cost and emissions performance were compared to other hydrogen production pathways. A Python-based model was created using Cantera, a chemical kinetic and thermodynamic library, to simulate the isothermal Pd membrane reactor. In the reactor, ammonia decomposes to nitrogen and hydrogen, while hydrogen is separated using the membrane. This eliminates the need for additional hydrogen purification steps. The base case achieved 99.92% conversion and 95.9% hydrogen recovery. To preheat the ammonia feedstock to the membrane reactor, the unconverted ammonia and unrecovered hydrogen were mixed with some ammonia feedstock and combusted with air. The combustion generates NOx emissions, which were reduced by 85% using a selective catalytic reduction unit, bringing NOx emissions well below provincial limits. While the system has no direct carbon dioxide emissions, indirect emissions from electricity consumption, ammonia feed and transportation for the process were estimated at 4.86 kg CO₂e/kg H₂, with an electricity requirement of 9.77 kWh/kg H₂. An economic analysis shows a capital expenditure of approximately $204,000 and an annual operating cost of $1.6 million for the base case. The levelized cost of hydrogen (LCOH) at 350 bar was estimated at $10.38 kg/H2. A sensitivity analysis was also conducted to evaluate the impact of temperature, pressure and membrane permeance on conversion, hydrogen recovery, NOx emissions, and LCOH. The impact of capital and operating expenditure on LCOH was also analyzed, with the price of ammonia being the main contributor to changes in LCOH. These results from a detailed study of the ammonia to hydrogen pathways contribute to a better understanding of clean hydrogen technologies for transportation applications and also provide key insights for future deployment in clean fuel strategies across Ontario and beyond.
Techno-economic and Life Cycle Assessment of Airport Hydrogen Production Infrastructure for Future Hydrogen-based Aviation
(University of Waterloo, 2025-08-21) Ye, Zhen
The aviation sector faces growing pressure to reduce emissions, as global air travel continues to expand and jet fuel demand rises. Alternatives such as sustainable aviation fuel (SAF), battery electric, and hydrogen have emerged to reduce dependence on fossil fuels. While SAF offers partial emissions reductions, and electric aviation remains constrained by battery weight and power limitations, hydrogen presents a promising long-term solution. Hydrogen can be used to generate power via combustion or fuel cells, offering the potential for zero carbon emissions. However, implementing hydrogen-based aviation fuel faces challenges, particularly in establishing adequate infrastructure for cost-effective hydrogen production and supply. In addition, it is costly to distribute hydrogen, and early adoption is likely constrained by the availability of a reliable fuel supply chain. This study explores the feasibility of achieving low-carbon hydrogen supply through on-site hydrogen production at airports, integrated with renewable energy sources (RES) and the electrical grid, to increase hydrogen independence and avoid long-distance hydrogen distribution. A mixed-integer linear programming (MILP) model is used to determine the optimal component capacity configuration of the on-site hydrogen facility, considering both economic and energy constraints. Under base-case techno-economic assumptions, an optimal configuration results in an annualized total cost of US$22.7 M and a levelized cost of hydrogen (LCOH) of US$7.45 per kg of liquid hydrogen (LH2). Sensitivity analyses reveal that the system’s economic performance and operational patterns are significantly affected by variations in component unit costs and efficiencies. Compared to a system powered solely by RES, integrating grid electricity improves both economic viability and energy efficiency. Simulations using projected parameters for 2050 demonstrate the potential for reducing LCOH reduction while increasing RES utilization. Additionally, life cycle assessment (LCA) of the renewable-based hydrogen infrastructure reveals carbon intensities (CI) between 1.47 and 4.17 kg CO₂-eq/kg LH2, which are 3 to 8 times lower than that of fossil jet fuel, highlighting the environmental benefits of renewable hydrogen. The highest emissions are found to be associated with manufacturing RES and storage components due to the use of fossil fuel in material processing. Results also show trade-offs between economic and environmental performance of renewable hydrogen infrastructure in airports: Wind turbine (WT)-powered configuration offer stronger environmental benefits at a higher cost. This underscores the importance of balancing cost and emission reduction in onsite hydrogen infrastructure design for airports.
Engineering Solid Oxide CO2 Electrolysis: From Nanoparticle-Decorated Perovskite Cathode to System-Level Modeling
(University of Waterloo, 2025-08-21) Emadi Foshtomi, Seyed Mohammadali
Solid oxide electrolysis cell (SOEC) is a promising technology for CO2 electrolysis and subsequent conversion to useful chemicals. This thesis combines the experimental development of new cathode materials with system-level simulation to enhance the performance of SOECs for CO2 electrolysis and assess their applicability for fuel production. There are two components to the work: (1) proposing nanoparticle decorated perovskite cathode material and (2) integration of DAC, SOEC and synfuel production and asses its performance with techno-economic and environmental analysis. In the experimental section, the focus was on the cathode material of the SOEC since it is the limiting factor for CO2 electrolysis. Sr2Fe1.5Mo0.5O6-δ (SFM) has attracted much attention due to its decent performance of CO2 electrolysis. To enhance the SFM performance, it was modified by doping bismuth and nickel to make a new composition of Bi0.1Sr1.9Fe1.4Ni0.1Mo0.5O6-δ (BiSFNiM). The Ni-doping made it possible for Fe–Ni nanoparticles to exsolve in situ when the material was reduced by 5% H2/Ar. Structural characterizations like XRD and Rietveld refinement showed that, during exsolution, the material changed from a pure double perovskite structure to a mixed-phase material with both Ruddlesden–Popper (RP) and residual double perovskite phases and metallic nanoparticles. Using electron microscopy (SEM/TEM/EDS), it showed that Ni migrated to the surface of the perovskite bulk where it forms Fe–Ni nanoparticles. This material, then, was used as the cathode of SOEC and the results showed that these exsolved Fe–Ni nanoparticles significantly improved the electrocatalytic activity for the CO2 reduction reaction (CO2RR). Electrochemical performance tests demonstrated substantial improvements in current density and polarization resistance. The fabricated cell achieved a peak current density of 1.3 A/cm² at 800 °C under an applied voltage of 1.6 V, while it was 1.0 A/cm² for the non-exsolved nanoparticles sample. The second half of this thesis was a process simulation and system-level evaluation of an integrated DAC-SOEC facility. The technology was based on capturing 250,000 tonnes of CO2 from the air each year and turning it into either methanol or synthesis fuel through downstream processes. Methanol production was 36.4 tonnes per hour, while synfuel output was 15.1 tonnes per hour. The techno-economic analysis found that the levelized production cost for methanol was $1.32 per kilogram (nearly double the current market price) and for synfuel, it was $2.78 per kilogram (approximately 45% more than normal expenses). Using Ontario’s electricity grid mix, the simulated plant achieved greenhouse gas emissions of 31.1 gCO2-eq/MJ for methanol and 5.2 gCO2-eq/MJ for synfuel, the latter representing a reduction compared to conventional fossil-based pathways (40 g-CO2-eq/MJ-MeOH and 29 g-CO2-eq/MJ-synfuel). Further sensitivity analysis demonstrated that switching to fully renewable electricity sources, such as hydropower or wind, could push the synfuel production case into a net-negative emissions region. In conclusion, this thesis contributes to both fundamental and applied aspects of CO2 electrolysis. On the material side, it offers a strong plan for boosting cathode performance by co-doping and nanoparticle exsolution. It also gives information about phase stability, exsolution behavior, and catalytic activity. At the system level, it shows that combining DAC and SOEC for sustainable fuel production is possible from a technological, economic, and environmental point of view. The dual approach shows how innovative materials and systems design can work together to help us toward carbon-neutral chemical manufacture.
Sustainable Agrochemical Delivery Systems Based on Cellulose Nanocrystals and Chitosan
(University of Waterloo, 2025-08-20) Cao, Gaili
Bio-derived materials offer key advantages such as sustainability, biodegradability, non-toxicity, high loading capacity, and tunable physicochemical properties, making them excellent candidates for the design of environmentally friendly agricultural formulations. Surfactants, commonly used additives in pesticide formulations, possess good interfacial control performance. Their combination with bio-derived materials not only offers new insights into the development of sustainable pesticide formulations but also broadens their application with novel functionalities. In this thesis, we focus on the synergistic interactions of the bio-based materials and surfactants in (a) improving pesticide encapsulation efficiency, (b) controlling the behavior of pesticide-containing droplets on hydrophobic plant surfaces, and (c) facilitating the development of water-based and sustainable pesticide formulations. We developed a strategy to enhance pesticide loading and droplet deposition by mixing small amounts of sodium dodecyl sulfate (SDS) (0.1 wt%) and cationically modified cellulose nanocrystals (PCNC). The reduced surface tension, increased viscosity and adhesion, and electrostatic and hydrogen interactions between SDS/PCNC complexes and plant surfaces resulted in a low retraction velocity, excellent spreading and resistance to air turbulence. The improved loading content was facilitated by the hydrophobic domain of PCNC and SDS micelles. However, such formulations exhibit limited effectiveness on superhydrophobic surfaces. To address this, we developed an advanced pesticide formulation capable of effectively controlling droplet splashing and rebound on superhydrophobic surfaces. CNC modified with tannic acid and copper ions was selected as nanocarriers for hydrophobic pesticides, methylcellulose (MC) served to enhance the viscous dissipation and mechanical integrity of the liquid, and surfactant Aerosol OT (AOT) was indispensable in improving its affinity toward non-wetting surfaces and mitigating capillary forces. The resulting formulation reduced surfactant usage to 0.1% and successfully formed a network structure, offering several advantages. These include excellent wetting capacity on superhydrophobic surfaces, a deposition efficiency of 88.92%, which is 17 times higher than that of water, enhanced resistance to wind and rain erosion, and improved insecticidal efficacy. Notably, this "ideal" pesticide formulation can be stored in a solid form, effectively overcoming the challenges associated with the storage of emulsion-based pesticide formulations. However, the above systems are derived from fossil fuels, raising concerns about their sustainability and safety. Therefore, we explore a sustainable and effective alternative, where we developed a biosurfactant (QCS) derived from biodegradable, sustainable, and abundantly available chitosan. QCS exhibits excellent capability in modulating surface and interfacial properties and adjusting liquid rheology. These features help suppress droplet splashing and rebound on hydrophobic surfaces, improve pesticide deposition, and increase resistance to environmental erosion. Compared with the pesticide formulation using fossil-based surfactants (SDS and AOT) and CNC, the delivery system composed only of QCS is simpler and can inhibit droplet splash on hydrophobic plant surfaces, including superhydrophobic ones. Moreover, QCS alone could reduce the surface tension to 27.35 mN/m and markedly increase the liquid viscosity, without the need for additional polymers or CNC. It could also enhance deposition efficiency to approximately 62.0%. Beyond foliar sprays, QCS, with its excellent film-forming ability and abundant functional groups, is also suitable for soil-based delivery systems, such as mulch films and hydrogels. Both showed strong water retention capabilities, meeting the water-conservation needs of arid and resource-limited agricultural environments. The broader implications of this work align with key United Nations Sustainable Development Goals. These systems exhibit sustained release profiles, with cumulative release ranging from 90% within 48 h to 42.4% after 500 h. QCS offers diverse and sustainable pesticide delivery options. This work introduces a versatile biosurfactant that not only supports sustainable agriculture but also holds promises for broader applications in surfactant-reliant fields such as detergents, drug delivery, and biomedical formulations.
Regulating Interlayer Spacing and Defects on Nitrogen-Doped Hard Carbon Anodes from Waste Plastic for Sodium-Ion Batteries
(University of Waterloo, 2025-08-19) Lu, Qiran
Sodium-ion batteries (SIBs) are regarded as a promising option among rechargeable batteries for energy storage systems (ESS) due to low-cost and abundant sodium source. One of the key bottleneck problems constraint their commercialization progress is the lack of suitable anode. As a potential choice, hard carbons emerge because of their unique microstructure and sustainable precursors. Nevertheless, capacity and cycling performance of hard carbons are not satisfactory for market needs. The performance of hard carbon is linked to three key microstructural parameters: interlayer spacing, pore architecture, and defect. Suitable interlayer distance enables sodium ions intercalation, while closed pores allow sodium ions fill into. Defect sites on surface facilitate the adsorption of sodium ions. Lasted researches indicate element doping affects both interlayer spacing and defect concentration in hard carbons. It is worth mentioning that waste plastics is a global issue, while these carbon-contained waste are possible to be used as hard carbon precursor. In this thesis, we employed waste polyethylene terephthalate (PET) as raw material, combining with nitrogen doping technique, synthesized nitrogen-doped hard carbon (NHC) as anode for SIBs. This hard carbon contains expanded interlayer and various defect sites, enhancing overall electrochemical performance. Using as anode, it delivers a reversible capacity of 340.4 mAh g⁻¹ at 20 mA g⁻¹. At the same time, the complex sodium storage behavior is unveiled by a series of electrochemical measurements. This research not only fulfills the demand of high-performance SIBs anodes, but also promotes a sustainable future.
CO2 conversion to light hydrocarbons over K/Fe2O3-Al2O3 synthesized via the reverse microemulsion method
(University of Waterloo, 2025-08-12) Lin, Zixuan
The increasing concentration of atmospheric carbon dioxide (CO2), primarily driven by human activity, has intensified global concerns over climate change. One promising strategy to address this issue is the catalytic conversion of CO2 into valuable hydrocarbons, offering a sustainable route for emission reduction and fuel production. Potassium-promoted iron-based catalysts were investigated for CO2 hydrogenation via a modified Fischer–Tropsch (FT) process. High specific surface area catalysts were synthesized using the reverse microemulsion method, enabling controlled particle size and dispersion. The effects of potassium (K) loading (0-11.3 wt%), active phase, support, H2:CO2 feed ratio (1-4), reaction temperature (300-500 °C), pressure (4-12 bar), and GHSV (750-4000 mL/(gcat∙h)) were examined. Catalytic performance was evaluated by CO2 conversion, C2+ hydrocarbon selectivity, and space time yield (STY). Fresh and spent catalysts were characterized using XRD, TPR, BET, TEM, TGA-FTIR, and ICP techniques. The 7.8%K/Fe2O3-Al2O3 catalyst exhibited the highest activity, achieving 50% CO2 conversion, 53% C2+ selectivity, and a STY of 7.72 mmol/(gcat∙h) at 11 bar, 1000 mL/(gcat∙h), and 400 °C. In contrast, the catalyst without potassium showed significantly lower performance, with 24% conversion, 12% selectivity, and a STY of 0.87 mmol/(gcat∙h). The enhanced activity is attributed to the formation of active χ-Fe5C2 and Fe3O4 phases under reaction conditions, facilitated by the uniform nanoscale morphology of the catalysts synthesized via the reverse microemulsion method.
Carbon-Doped Silicon Nanoparticles in Thermally Reduced Graphene Oxide Composites for High-Capacity Lithium-Ion Battery Anodes
(University of Waterloo, 2025-07-31) Zamperoni, Ryan
Silicon is a promising anode material for next-generation lithium-ion batteries due to its high theoretical capacity (3600 mAh/g), natural abundance, and low cost. However, its practical application is limited by severe ~300% volume expansion during lithiation, leading to rapid capacity fading and poor cycling stability. In this work, recent literature on silicon anodes is reviewed and compared using a novel framework, highlighting the challenge of achieving stable cycling at high areal loadings. Building on these insights, carbon-doped silicon nanoparticles, which are known for their ability to mitigate lithiation-induced stress, are investigated in thermally reduced, spray-dried core-shell composites with reduced graphene oxide (rGO). The thermal reduction temperature of rGO is also varied to assess its impact on electrochemical performance. When encapsulation by rGO was effective, the carbon-doped silicon nanoparticles enhanced both rate performance and cycling stability of the core-shell silicon-rGO composites (Si@rGO), compared to undoped silicon. Among the tested reduction temperatures, 950 °C yielded the best rate performance, balancing rGO deoxygenation (which improves conductivity) with the formation of inactive silicon carbide at higher temperatures (which lowers specific capacity). The optimized Si@rGO composite, featuring carbon-doped silicon and reduced at 950 °C, delivered a specific capacity of 957 ± 53 mAh/g with 74.8 ± 2.4% capacity retention after 160 cycles. Finally, the energy density of a theoretical full battery pairing with NMC881 was estimated, projecting an 18% increase in energy density over a conventional graphite–NMC881 cell at commercial mass loadings.
Engineering a Synthetic Bacterial Consortium of Escherichia coli and Pseudomonas putida for Mixed Plastic Monomer Bioprocessing
(University of Waterloo, 2025-07-17) Dharmasiddhi, Ida Putu Wiweka
Plastics are indispensable to modern life, but their widespread use has created an environmental crisis due to inefficient waste management. Mixed plastic waste, comprising diverse polymers, presents significant recycling challenges due to the high costs of sorting and processing, leading to ecosystem accumulation and harmful by-product generation. This study addresses this issue by engineering a synthetic bacterial consortium (SBC) designed to degrade mixed plastic monomers. The consortium pairs Escherichia coli Nissle 1917, which uses ethylene glycol (EG), a monomer derived from polyethylene terephthalate (PET), as a carbon source, with Pseudomonas putida KT2440, which metabolizes hexamethylenediamine (HD), a monomer from nylon-6,6, as a nitrogen source. Adaptive evolution of the SBC revealed a novel metabolic interaction where P. putida developed the ability to degrade both EG and HD, while E. coli played a critical role in degrading glycolate, mitigating its by-product toxicity. The evolved cross-feeding pattern enhanced biomass production, metabolic efficiency, and community stability compared to monocultures. The consortium’s performance was validated through constraint-based modeling, high-performance liquid chromatography (HPLC), and comprehensive growth assays. These findings highlight the potential of cross-feeding SBCs in addressing complex plastic waste, offering a promising avenue for sustainable bioremediation and advancing future polymer degradation strategies.

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