Bioinseneeria instituut

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listelement.badge.access-status Open Access ,
A comparative life cycle assessment of hydrogel and polydimethylsiloxane (PDMS) actuators
(Tartu Ülikool, 2026) Morozov, Vjacheslav; Torop, Janno, juhendaja; Tkaczyk, Alan Henry, juhendaja; Özcan Kilcan, Cansu, juhendaja
This thesis compares the environmental performance of a cellulose-based hydrogel actuator and a polydimethylsiloxane (PDMS) actuator. A cradle-to-gate life cycle assessment (LCA) was conducted for the production of a single 10 g actuator. Both systems were modeled in OpenLCA 2.4.1 using the Ecoinvent database version 3.11 and assessed with the Environmental Footprint (EF) v3.1 midpoint LCIA method. The results showed greater impacts from the PDMS actuator across most impact categories; for example, PDMS had about 166% higher climate change impact and about 118% higher non-renewable energy demand than the hydrogel actuator, while hydrogel generally showed a lower environmental profile.
listelement.badge.access-status Open Access ,
Bismuth as a Desalination Electrode Material
(Tartu Ülikool, 2025) Agbomeji, Habeeb Olatunbosun; Grozovski, Vitali, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Addressing freshwater scarcity and the energy demands of desalination, capacitive deionization (CDI) offers an energy-efficient solution for brackish water treatment by applying low voltages (~1.2 V) to capture ions on charged electrodes. Conventional carbon-based CDI, however, is limited to low salt removal capacities (~15 mg/g). To enhance performance, hybrid-CDI with Faradaic electrodes, such as bismuth (Bi) nanopowders, is explored for high-capacity, cost-effective chloride capture, and possible desalination of the seawater. This study investigates two morphologically different Bi nanopowder electrodes in 0.1 M NaCl, revealing a sequential electrochemical mechanism - Bi to Bi₂O₃, BiOCl, and BiCl(OH)₂. Both samples exhibit near-reversible oxide formation, diffusion-controlled oxychloride production, and surface-confined hydroxylated oxychloride formation, though cathodic irreversibility poses challenges for complete film reduction. These findings highlight Bi electrodes’ potential for sustainable CDI desalination, with given morphology and purity offering significant advantages.
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Brain Atrophy and Neuron Loss in the 5xFAD Mouse Model of Alzheimer's Disease
(Tartu Ülikool, 2025) Khazhmuratova, Zhanel; Hickey, Miriam Ann, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The 5xFAD mouse model is a well-known genetic model of Alzheimer’s disease (AD) that replicates key markers of the disease in humans and is widely used in AD research. However, clear and comprehensive evidence of neurodegeneration in this model is lacking. In this study, serial stereological cryosections from female 5xFAD transgenic and wild-type littermate mice at 9 and 14 months of age were analysed using machine learning-based tools, and the structural and cellular changes were compared between genotypes. We revealed a significant reduction in striatal and cortical volumes at 9 months, followed by hippocampal volume reduction at 14 months. At 9 months, cell detection analysis revealed a significant loss of neurons in the striatum, providing, to our knowledge, the first evidence of neuronal loss in the striatum of 5xFAD mice. These changes precede the emergence of severe cognitive dysfunction in this model and align with imaging data from human AD patients showing that striatal neurodegeneration correlates with the appearance of dementia. Although the striatum is not typically the primary focus of AD research, our findings highlight its important involvement in disease progression and as a target for further research.
listelement.badge.access-status Open Access ,
Brain-derived neurotrophic factor profiles in type 1 diabetes: a comparison between patients with and without ketoacidosis
(Tartu Ülikool, 2026) Mazure, Liva; Tagoma, Aili, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Type 1 diabetes (T1D) is a common metabolic autoimmune disease, especially in young people. It is often accompanied by several comorbidities and complications, including diabetic ketoacidosis (DKA), a serious acute metabolic disorder, which can cause neuronal alterations. Brain-derived neurotrophic factor (BDNF) is a neurotrophin involved in neuronal function and metabolic regulation, suggesting a potential association between BDNF and DKA. The aims of this study were to evaluate the associations between BDNF and DKA in individuals recently diagnosed with T1D, assess longitudinal changes in BDNF levels in samples collected 1–3 years after T1D diagnosis, and identify clinical covariates associated with BDNF levels. BDNF levels were measured from serum samples with the ELISA method. No statistically significant association between DKA and BDNF was found at either timepoint and the BDNF level remained stable in follow-up samples. Covariates associated with the level of BDNF included the presence of enterovirus IgG and IgA antibodies, the presence of GAD autoantibodies, C-peptide and IFN-γ levels, male sex, and ketonuria. In conclusion, BDNF levels in T1D were not associated with DKA and remained stable during the first years after diagnosis. BDNF could be more closely connected with immunological and metabolic factors relevant to T1D.
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Cell-Penetrating Peptide Nanoparticles for Delivery of Splicing-Correction Oligonucleotides and DNA Origami
(Tartu Ülikool, 2025) Mazur, Oleksandr; Porosk, Ly, juhendaja; Pooga, Margus, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Cell-penetrating peptides (CPPs) are emerging as versatile, non-viral vehicles for nucleic-acid therapeutics, yet their cargo range and in-cell efficiency remain limited. In particular, most studies have not compared how the same CPP sequence handles cargos of very different size and architecture; moreover, there have been no attempts yet to deliver the DNA origami using the CPPs. Here, we asked how the three PepFect14-derived CPPs — PF14, Peptide 1, and PF14-Lys-Ile9 — perform with small versus bulky nucleic acids. Nanocomplexes were prepared by simple aqueous mixing and characterised by DLS/TEM, giving uniform spheroidal particles 100–160 nm in diameter (PDI ≤ 0.30). Functional delivery was then benchmarked for (i) a splice-correction oligonucleotide (SCO-705), (ii) a fluorescent three-arm DNA-origami probe (Nano-Cy3), and (iii) a luciferase-silencing siRNA embedded in, or tethered to, the same origami scaffold. In HeLa pLuc705 cells, Peptide 1 restored luciferase ~34-fold, exceeding PF14 (24-fold) and PF14-Lys-Ile9 (21-fold), while flow cytometry showed PF14-Lys-Ile9 achieved the highest Nano-Cy3 uptake in U87 cells without a corresponding gain in splice rescue, pinpointing endosomal escape as the bottleneck. With siRNA packed into the native LUC nanohydrogel, PF14-Lys-Ile9 drove the deepest knock-down (~72 %), whereas activity halved when siRNA was supplied as an isolated linker duplex. Overall, Peptide 1 is best suited to delivering small oligonucleotides, whereas PF14-Lys-Ile9 is more effective for larger, origami-based constructs — insights that chart distinct optimisation routes for future CPP nanocarriers.
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Cell-penetrating peptides for in vitro delivery of small interfering RNA and splice-correcting oligonucleotides
(Tartu Ülikool, 2026) Khrystynchenko, Polina; Porosk, Ly, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Optimization of carrier systems is required to enhance the development of nucleic acid therapies. Cell-penetrating peptides (CPPs) are promising transport vectors for this purpose, which can form nanoparticles with therapeutic nucleic acids and facilitate their transport to intracellular targets. As part of this work, the potential of five amphipathic PepFect14-based CPPs complexed with small interfering RNA (siRNA) and splice-correcting oligonucleotides (SCOs) was studied in the formation of nanoparticles and the delivery of nucleic acid into the cell. All new analogs tested formed CPP-nucleic acid complexes with both siRNA and SCOs. In addition, the stability of CPP/siRNA nanoparticles was tested against enzymatic degradation and polyanionic heparin. The four analogs possessed a suitable profile as siRNA transport vectors, while only two analogs were suitable as tested under the given conditions for both siRNA and SCO. None of the CPP/siRNA and CPP/SCO nanoparticles tested had a significant impact on cell viability.
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Characterising a Novel HNH-Domain Containing Bacterial Immunity System From Escherichia coli
(Tartu Ülikool, 2025) Aliyeva, Elfi; Mets, Toomas, juhendaja; Abdullah, Minhal, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Bacteria are constantly in danger of being attacked by bacterial viruses - bacteriophages. To combat the threat, bacteria have developed a wide array of intricate and diverse immune systems. Phage therapy’s growing popularity has led to increased interest in bacterial immunity. My thesis investigates one such potential immunity system from Escherichia coli, discovered by our colleagues at Lund University, named Bogomol. It is predicted to be comprised of an HNH-containing endonuclease domain and a C-terminal domain of unknown function. I validated Bogomol as an immunity system acting against certain phages of Straboviridae. This was done by performing efficiency of plating assays and liquid culture experiments against the BASEL phage library. As an attempt to further investigate the triggers of Bogomol, escape mutant experiments were also conducted.
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Characterization of HEMK2 in nuclear shape regulation
(Tartu Ülikool, 2026) Raimkul, Adiya; Mutso, Margit, juhendaja; Brūmele, Baiba, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Nuclear morphology is a widely used characteristic in clinical diagnostics, and alterations in nuclear shape are associated with a variety of disorders. Nuclear shape is determined by multiple factors, including intranuclear proteins, cytoplasmic forces, and genome organization. Recent studies have suggested that epigenetic regulation by methyltransferases may also influence nuclear shape. HEMK2 is a Class I methyltransferase that is associated with translation termination, cell proliferation, gametogenesis, and various diseases, including cancer and neurological disorders. Although some methyltransferases are associated with nuclear shape, no similar link has previously been reported for HEMK2. Therefore, the main purpose of this study was to investigate whether HEMK2 affects nuclear shape in U2OS cells. The results of this study suggest that HEMK2 is associated with nuclear shape abnormalities, as evidenced by nuclear invaginations in HEMK2-depleted cells. Additionally, lamin A/C expression level was shown to be altered among cell lines. Lastly, HEMK2 was reported to be predominantly cytoplasmic in U2OS cells. In summary, this study suggests that HEMK2 is associated with nuclear morphology in U2OS cells, and this association may be independent of HEMK2's methylation function.
listelement.badge.access-status Open Access ,
Characterization of Microbial Community Present on Communal Surfaces with Antimicrobial Coatings
(Tartu Ülikool, 2025) Mehraliyeva, Laman; Ivask, Angela, juhendaja; Harleen Kaur, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Microbial contamination on high-touch communal surfaces poses a risk to human health. While traditional cleaning methods such as disinfection and washing are commonly used, they may be limited by human error, reduced microbial susceptibility, or the need for frequent reapplication. Antimicrobial coatings offer a promising alternative by providing persistent protection through mechanisms that inhibit microbial growth or attachment. Copper is one of the most frequently present materials in currently marketed antimicrobial coatings. The main aim of this study was to examine the bacterial communities on the handles of shopping baskets covered with metallic copper and to compare them with handles that had no copper surfaces. Microorganisms were collected from the handles using moistened cotton swabs, and the collected samples were used to count aerobically growing bacterial colonies. To eliminate the DNA of non-viable bacterial cells from community analysis, propidium monoazide dye (PMA), which is expected to bind the DNA of dead or heavily damaged bacteria, was added to part of the samples. Then, DNA was extracted from the samples, and sequencing libraries were constructed. The microbial communities on surfaces were identified through sequencing of the 16S rRNA variable region and analyzed using statistical tools. The results showed that basket handles coated with copper had significantly fewer aerobically growing bacterial colonies and lower species richness compared to the handles without copper surfaces. Additionally, the microbial taxa present on the surface differed from those found on uncoated handles. Treatment of the surface-collected microbial communities with PMA further influenced the composition of the microbiome. These findings suggest that copper-based antimicrobial coatings may reduce microbial burden and diversity on surfaces, and that PMA treatment is a valuable tool to use in experiments for differentiating between live and dead or significantly damaged microbes in DNA-based studies.
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Characterization of stress responses in pseudomonas putida using plasmid-based fluorescent reporter systems
(Tartu Ülikool, 2026) Grigorjeva, Julija; Jõesaar, Merike, juhendaja; Viggor, Signe, juhendaja
The rising interest in implementing microbial biosynthesis strategies for production of high-value compounds, as an alternative to traditional chemical manufacturing, has facilitated the development of microbial bioengineering. However, numerous valuable target substrates and products, such as C1 compounds and terpenoid-related molecules, exhibit considerable toxicity to microbial hosts, which limits their industrial application. Consequently, for the construction of more reliable strains the stress response pathways are aimed to be thoroughly studied. Nonetheless, well-characterized stress response reporter systems remain scarce for the recently emerged Pseudomonas putida as a model organism. This study aimed to evaluate the performance of engineered stress-response reporter constructs in P. putida and to investigate the stress responses induced by different valuable compounds. A series of fluorescence-based experiments was conducted in order to assess reporter systems’ performances in terms of sensitivity, response kinetics and strain stability during the chemical exposure to methanol, formate, isoprenol and lycopene. The results suggested that P. putida can tolerate relatively high concentrations of methanol, which mainly caused membrane and growth stress, formate that triggered mild stress from the DNA damage, and membrane and growth stress after the prolonged exposure, and lycopene, inducing the stress from the DNA integrity disruption. In contrast, even low concentrations of isoprenol induced moderate genotoxic effects and severe membrane and growth stresses.
listelement.badge.access-status Open Access ,
Characterizing the genomic diversity of prevalent gut microbiome bacterial species using metagenome-assembled genomes
(Tartu Ülikool, 2026) Kholonivskyi, Oleksandr; Pantiukh, Kateryna, juhendaja; Krigul, Kertu Liis, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Metagenome-wide association studies enable the identification of associations between the human microbiome and host physiological traits, such as inflammatory bowel disease, type 2 diabetes, and mental disorders, as well as many other physiological features, including diet, stress, exercise, and drug intake. In these studies, microbiome composition is typically characterized at the species level. As the gut microbiota is known to exhibit structured diversity below the species level, association studies at the within-species level may yield stronger associations. A major challenge is that the within-species structure of most gut microbial species remains poorly defined. In this study, we investigated the within-species structure of the five most abundant and prevalent microbial species using open data. The results showed clear within-species structures for four of the five species.
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Co-Expression Analysis of Sigma-1 Receptor and Tetraspanins: Insights into the Biogenesis of Sigma-1 Receptor-Enriched Extracellular Vesicles
(Tartu Ülikool, 2025) Mathur, Chaitanya; Vāvers, Edijs, juhendaja; Kopantšuk, Sergei, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Sigma-1 receptor (S1R) is a chaperone protein that resides in the endoplasmic reticulum. Recently, S1R has been associated with the generation of extracellular vesicles (EVs). Set of tetraspanins were used as markers for EVs and they were co-express with S1R in mammalian cells using MultiBacMam system. Validation of expression profiles and fluorescent intensities was performed by fluorescence spectroscopy and microscopy. Conditioned cell media was used to isolate EV particles using Tangential Flow Filtration and single-particle analysis with Total Internal Reflection Fluorescence Microscopy was performed to gain insights into the biogenesis of the S1R enriched EVs.
listelement.badge.access-status Open Access ,
Combinatorial Effect of Histone H3 and H4 Mutations with Deletion of YEATS Domain Protein Sas5 in Saccharomyces cerevisiae
(Tartu Ülikool, 2025) Dey, Noah Jabis; Värv, Signe, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The single cell eukaryote, Saccharomyces cerevisiae or budding yeast, synthesizes three YEATS domain containing proteins associated with chromatin remodelling and modifying complexes. Previous experiments have shown that deletion of either of the YEATS domain containing proteins, Taf14 or Yaf9, in combination with mutations in the N-terminal tails of histones H3 and H4 is lethal for the cells. In this thesis the aim was to assess the effects of deletion of SAS5, the third YEATS-domain containing protein, in combination with mutations in histones. A decrease in the viability for cells carrying sas5Δ and H3 acetylation and methylation mutations was detected.
listelement.badge.access-status Open Access ,
Describing the non-canonical restriction-modification type II system (RMII) in pseudomonas putida PaW85
(Tartu Ülikool, 2026) Syritka, Oleksandr; Ainelo, Andres, juhendaja; Tamman, Hedvig, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Bacteriophages are the most abundant biological entities on Earth and exert a major selective pressure on bacterial populations. To counteract phage infection, bacteria have evolved a diverse arsenal of anti-phage defense mechanisms, among which Restriction-Modification (RM) systems are the most prevalent. RM systems protect the host by methylating self-DNA at specific recognition sequences while cleaving incoming foreign DNA that lacks the corresponding modification. This thesis focuses on a non-canonical type II RM system (RMII) encoded in Pseudomonas putida PaW85, a biotechnologically important soil bacterium. The RMII locus comprises a putative restrictase (R, PP_3988) and two distinct methylases (M1, PP_3989 and M2, PP_5651). Using phage susceptibility assays with an expanded CEPEST phage collection, the system was confirmed to reduce infection efficiency of phages from genus clusters G16 and G17 by up to 200-fold. To determine the functional contribution of each methylase, deletion strains lacking either or both methylases were constructed and used for restrictase expression experiments. Both methylases were shown to be important, which refers to redundancy. Bioinformatic and structural analyses show that the M1 and M2 are unrelated, probably coupled together by horizontal gene transfer. M1 is a cytosine methyltransferase with structural similarity to methylases of known type IIA(S) systems, while M2 is evolutionarily unrelated to M1 and shares structural similarity with adenine methyltransferases. These findings characterize a non-canonical RMII system in P. putida PaW85 and provide a foundation for future biochemical studies of the restrictase and for informed genomic engineering of this industrially relevant bacterium for possible biotechnological applications.
listelement.badge.access-status Open Access ,
Development of an Autonomous Open-Source Inventory Performance Robot for the University of Tartu Library
(Tartu Ülikool, 2025) Zvirgzdina, Robina; Raudmäe, Renno, juhendaja; Vunder, Veiko, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Inventory management is crucial for the successful functioning of a venue. Manual inventory management and asset tracking can be time-consuming, dull, and inefficient. In particular, in large-scale libraries, it can take personnel months to perform a single inventory round of all the books. Nowadays, using advanced robotics solutions, it is possible to automate the process and provide more accurate information on the availability and location of the desired book. This results in higher satisfaction for librarians and visitors, as they can successfully find the books of interest. This thesis aims to create an open-source solution that contains a radio frequency identification system for the University of Tartu library. The result is intended to use the Robotont project as a base platform. It should be able to autonomously navigate through library halls while scanning the bookshelves and adjusting the antenna height for it to be at the same level as the books. Simultaneously, it should document the book IDs and their location to produce a heat map containing the most probable location for each book.
listelement.badge.access-status Open Access ,
Development of low-level control system for the KuupKulgur rover
(Tartu Ülikool, 2026) Turchak, Kateryna; Tammer, Andres Aleksander, juhendaja; Tepandi, Tarvi, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Modern extraterrestrial exploration relies on unmanned planetary rovers capable of conducting experiments on cosmic bodies autonomously. This work is a part of the Estonian microrover project KuupKulgur, a lunar explorer which requires a low-level control system for on-board motors as a part of its larger autonomy software stack. This thesis presents development of the control system for the rover’s 6 skid-steering wheels by implementing and enhancing a per-wheel PID controller. The algorithm is configurable to match frequent system improvements and constantly changing requirements of the project. It is developed as a Robot Operating System (ROS) node written in C++ to be easily integrated into the project’s ROS architecture. PID controller utilizes wheel encoder data for control input calculation, and features terrain adaptation and per-wheel correction logic aimed at handling terrain inconsistency. The control system was extensively tuned and tested on several surfaces including lunar regolith analogue at Tartu Observatory, with results presented in this thesis.
listelement.badge.access-status Open Access ,
Development of Taï Forest alphavirus trans-replicase assay systems in mammalian and insect cells
(Tartu Ülikool, 2026) Shabanova, Evgeniya; Koit, Sandra, juhendaja; Merits, Andres, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Taï Forest alphavirus (TALV) is a poorly characterised insect-specific alphavirus that has remained difficult to study since its discovery due to its inability to grow in standard cell cultures. This study investigates the TALV by developing a mammalian and insect cell-based trans-replicase assay system. To develop the assay, plasmids separating viral replication into two functional components, the replication driver (replicase) and the replication template (minigenome), were constructed and tested by transfection into respective cell lines. The trans-replicase and split trans-replicase systems were used to investigate the compatibility of the TALV minigenome with replicases of other alphaviruses and vice versa. These results offer the first functional analysis of TALV replication, revealing that it is temperature-sensitive and dependent on unknown factors. This insight establishes a baseline for future studies of this understudied alphavirus.
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Ecotoxicity of monomer, polymers and dihydrazides using Dapnia Magna and Spirodela Polyrhiza
(Tartu Ülikool, 2026) Mahal, Ayman; Vares, Lauri, juhendaja; Ismagilova, Alina, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The increasing use of synthetic monomers and polymers has raised concerns regarding their possible impact on aquatic ecosystems. Since monomers are important building blocks in polymer synthesis, evaluating their environmental safety is necessary for the development of safer materials. This thesis investigates the ecotoxicity of selected monomeric, polymeric and dihydrazide compounds using Daphnia magna and Spirodela polyrhiza as aquatic model organisms. The investigated compounds included 4-methacrylate-3-methoxyacetophenone (AVMA), poly(methacrylate-3-methoxyacetophenone) (P(AVMA)), poly(methyl methacrylate-co-methacrylate-3-methoxyacetophenone) (P(AVMA-MMA)), malonic dihydrazide and adipic dihydrazide. Toxicity assessment was performed using acute immobilisation assays with Daphnia magna and growth inhibition assays with Spirodela polyrhiza. The obtained results demonstrated that the AVMA monomer exhibited higher toxicity compared with the corresponding polymeric compounds and dihydrazides, while polymerization reduced the observed toxic effects toward the tested aquatic organisms. Additionally, Daphnia magna showed higher sensitivity to the investigated compounds than Spirodela polyrhiza. The results highlight the importance of ecotoxicological evaluation of monomers, polymers and dihydrazides to better understand their potential environmental impact.
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Effects of Disruption of Genes With Unknown Function in the C1-Fixing Gene Cluster on a Gas-Fermenting Acetogen
(Tartu Ülikool, 2025) Vorontsova, Mariia; Valgepea, Kaspar, juhendaja; Nwaokorie, Ugochi Jennifer, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Gas fermentation is a promising technology for producing chemicals, fuels, and feed proteins from greenhouse gases and solid waste using gas-fermenting microbes. Acetogens are the most attractive biocatalysts for gas fermentation as they can use C1 gases carbon monoxide (CO) and carbon dioxide (CO2) as their sole carbon source using the Wood-Ljungdahl pathway (WLP). Genes encoding WLP enzymes are located in a C1-fixing gene cluster that also contains several genes with unclear function. In this work, the role of two such genes were investigated through gene disruption in the model-acetogen Clostridium autoethanogenum. For this, CRISPR/Cas9n plasmids were constructed and used for knock-out (KO) of the glycine cleavage system H protein (gcvH) and double knock-out (dKO) of gcvH and the first 80 bp of the adjacent acsV gene. Phenotypic characterisation of ∆gcvH in autotrophic batch cultures revealed significant growth defects and altered yields of acetate and 2,3-butanediol (2,3-BDO) compared to the parental LAbrini strain. Additionally, ∆gcvH showed a very long lag phase during growth without yeast extract. Supplementing cultures with glycine shortened the lag phase but did not restore normal growth, suggesting gcvH involvement in glycine synthesis. Notably, the dKO ∆gcvH∆acsV strain failed to grow autotrophically and phenotypic characterisation of heterotrophic batch cultures revealed significant growth defects and higher 2,3-BDO and ethanol product yields compared to LAbrini. Our findings shed light on the potential links between the glycine cleavage system and WLP and contribute towards a better understanding of carbon fixation in acetogens.
listelement.badge.access-status Open Access ,
Electrode materials for water splitting in alkaline electrolysis
(Tartu Ülikool, 2026) Ivashyna, Anastasiya; Grozovski, Vitali, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Alkaline water electrolysis is a leading pathway to renewable hydrogen production, yet conventional immersed-electrode systems are constrained by bubble-induced mass transport losses and sluggish reaction kinetics. This study investigates NiMo cathodes and NiFe anodes fabricated by galvanostatic electrodeposition onto stainless steel mesh substrates (#300 and #400) for operation in a capillary-fed electrolysis cell, which supplies electrolyte via capillary action through a porous separator, enabling near bubble-free operation. The influence of mesh geometry, fluoropolymer chemistry (PTFE vs. PVDF), coating morphology, gas removal efficiency, and full-cell performance was evaluated in 1 M KOH. SEM and EDS confirmed Volmer–Weber island growth on both substrates, with the #400 mesh supporting higher nucleation density and more uniform elemental distribution. Three-electrode measurements showed NiMo reduces η10 by 222 mV and NiFe reduces η100 by 72–79 mV relative to uncoated #400 substrates. In full-cell testing, the #400 PTFE configuration achieved 1.85 V at 0.5 A and 2.18 V at 1.5 A, compared to 2.49 V at 1.5 A for the polymer-free baseline. Post-operation EDS revealed severe Mo leaching in NiMo cathodes and beneficial Fe enrichment in NiFe anodes consistent with active NiFeOOH reconstruction. The results demonstrate that full-cell performance is governed by the interaction between mesh pore geometry and fluoropolymer surface energy rather than intrinsic catalyst activity alone, with the #400 mesh paired with PTFE identified as the optimal configuration within the tested parameter space.

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