Plant diseases caused by pathogenic microorganisms result in significant damage to agriculture. Lactic acid bacteria (LAB), in particular strains of Lactiplantibacillus plantarum (L. plantarum), are used as one of the biocontrol methods against plant pathogenic bacteria due to high antagonistic activity associated with their metabolic potential. We have investigated the influence of nutrient medium components (various carbon and nitrogen sources) and cultivation conditions (temperature, duration, and pH) of L. plantarum strains on the level of their antagonistic activity against the test strains of plant pathogenic bacteria. The antimicrobial activity of LAB supernatants was maximal in the presence of 3% (30 g/L) sucrose as the main carbon source and 1% (10 g/L) tyrosine as the main nitrogen source in the nutrient medium against all investigated test strains of PPB. However, the use of such a carbon source as galactose or arabinose led to a decrease or even absence of antimicrobial properties of LAB against phytopathogenic bacteria. The optimal conditions for cultivation of lactobacilli were determined: cultivation temperature +30 ± 1°C, pH 7.8, and duration 72 h. Strains of L. plantarum 13c and 21c caused zones of inhibition in test pathogens from 298 to 291 mm. Whereas during 24‐h cultivation of LAB strains, their antagonistic activity was significantly lower, and the zones of inhibition decreased by 30%. The duration and temperature had a significant effect on increasing the antagonistic activity of L. plantarum strains, in contrast to the pH of the medium (p ≥ 0.05).

Background: Recent studies on the lysate of Lactobacillus rhamnosus DV have demonstrated its antimicrobial and fungicidal activities. Classical microbiological methods for evaluating postbiotics and metabiotics are resource-intensive that need for new rapid and sensitive tests systems to assess their antimicrobial and antifungal properties. Objectives: The aim of this work was to study the effects of the Lactobacillus rhamnosus DV lysate on the intensity of Photobacterium phosphoreum bioluminescence and to demonstrate the potential use of bacterial bioluminescence to determine the bacteriostatic activity of this postbiotic substance. Materials and methods: The cell lysates of lactic acid bacterial strain L. rhamnosus DV were investigated, which were included in the Del-Immune V® dietary supplement produced by MirImmunoPharm LLC (Ukraine) in cooperation with Stellar Biotics, LLC (USA). The culture of P. phosphoreum IMV B-7071 was used in this study. Bioluminescence measurements were conducted using a digital photo-registration method. Bioluminescence was analyzed using cross-platform open-source software ImageJ (NIH) in brightness units in RGB color space. Results: The bioluminescence intensity initially increased with population density during the first day, then faded despite the continued growth of cell density in the bacterial suspensions. The addition of Lactobacillus rhamnosus DV lysate significantly suppressed bioluminescence, reducing it to background levels within 24 hours, with the effect varying by concentration. The peak luminescence in control samples occurred at 18 hours, whereas in lysate-treated samples it shifted to 3–6 hours, depending on the lysate concentration. Conclusions: The lysate of Lactobacillus rhamnosus DV causes a significant decrease in the growth rate of Photobacterium phosphoreum and strongly suppresses the intensity of their bioluminescence, the magnitude of which depends on the concentration of the lysate. This finding supports the use of bacterial luminescence as an effective way for evaluating the bacteriostatic activity of postbiotic substances against pathogenic and opportunistic microorganisms.

This article presents a comprehensive review of current approaches to the automated design of biotechnological systems, with a particular focus on the role of mathematical modeling as a core tool of systems bioengineering. In the context of increasing complexity of biological entities and processes, the growth of multi-omics data, and the need to accelerate the development of novel biotechnological products, the integration of computational technologies into every stage of the biosystem life cycle is becoming critically important. The paper highlights key strategies that shape the emerging digital paradigm in biotechnology, including whole-cell modeling, the iterative Design-Build-Test-Learn (DBTL) cycle, deterministic and stochastic modeling, and Flux Balance Analysis (FBA). Special attention is paid to modern software platforms that enable practical implementation of these strategies—COPASI, CellDesigner, MATLAB SimBiology, Virtual Cell, Tellurium, among others. The article reviews recent trends such as the integration of machine learning methods into design optimization and predictive modeling, as well as the adoption of international biological modeling standards (SBML, CellML) that ensure model interoperability and reproducibility. Challenges such as the availability and quality of input data, the complexity of integrating diverse model types, and the need for interdisciplinary expertise and infrastructure support are also addressed. This review aims to summarize the current state of knowledge in the field of digital bioengineering and to outline the prospects for implementing these approaches in the Ukrainian scientific landscape, particularly in education, applied research, and industrial biotechnology development.

Background. Enhancing the efficiency of second-generation (2G) bioethanol production from lignocellulosic biomass is crucial for advancing sustainable biofuel technologies. However, the conversion of biomass into 2G bioethanol faces substantial challenges, necessitating a comprehensive investigation of microbial agents. Objective. To evaluate the effect of glucose and xylose concentrations, as well as cultivation duration, on the efficiency of ethanologenesis using the model organism Scheffersomyces stipitis UCM Y-2810, and to determine the optimal conditions for achieving maximum ethanol yield. Methods. The effects of glucose and xylose concentrations and cultivation time on ethanologenesis efficiency were evaluated using S. stipitis UCM Y-2810 as a model organism. The experimental design included three levels of factors: xylose concentration (3, 16.5, and 30 g/l), glucose concentration (1, 5.5, and 10 g/l), and cultivation durations (1, 2, and 3 days). Statistical analysis of the experimental data was conducted using a three-factor, three-level Box–Behnken design. Results. Under submerged cultivation of the strain of S. stipitis UCM Y-2810 in model media, optimization of the ethanologenesis process resulted in a maximum ethanol yield of 7.74 g/l. The optimal conditions for this yield were identified as follows: xylose concentration of 16.5 g/l, glucose concentration of 7.75 g/l, and a cultivation time of 3 days. Conclusions. The application of the Box–Behnken design revealed that the statistically significant factors influencing ethanologenesis efficiency were xylose concentration, yeast cultivation duration, and the linear-quadratic interaction between these two factors.

Introduction. Currently, research is being conducted to identify the mechanisms that enable living organisms to sense and utilize the Earth's magnetic field for orientation and navigation. The primary hypothetical mechanisms under active discussion include the radical pair model, which involves magnetosensitive free radical redox reactions in enzymatic systems containing oxygen molecules and flavin compounds (such as cryptochromes and bacterial luciferases), as well as the model involving intracellular magnetic magnetite particles interacting with the magnetic field. Our focus is on the first hypothesis. Therefore, the aim of our study was to investigate the effects of constant and extremely low frequency magnetic fields on the bioluminescence of Photobacterium phosphoreum, based on a flavin oxidation reaction. Notably, photobacteria are widely used as bioindicators of water pollution and indicators of exposure to various biologically active compounds. Methods. We measured the bioluminescence of P. phosphoreum in liquid media of standard composition for bacterial nutrient medium at room temperature (22-24°C). The baseline bioluminescence was evaluated over several days following inoculation in the culture medium. Bioluminescence was recorded using digital photoregistration, with subsequent image processing conducted in ImageJ or OriginPro. Magnetic field exposure was applied in two modes. In the first mode, bacterial suspensions were exposed to the magnetic field continuously from the moment of inoculation throughout the entire growth period. In the second mode, short-term magnetic field exposure was applied for several minutes after active hydrodynamic stirring of the bacterial suspension, which triggered a burst of luminescence, followed by fading and return to the baseline level. The magnetic field induction was measured using a Hall sensor. Results. Relatively strong static magnetic fields in the range of 2-8 mT weakly activated bioluminescence during the active growth phase of the bacterial population, but they statistically significantly suppressed the glow of bacteria during their maximum luminescence and subsequent dimming. The magnitude of the effects of the magnetic field was small, approximately 15% relative to the control values. The influence of a low-frequency magnetic field with a frequency of 7.85 Hz and induction of 100 μT stimulated the baseline bioluminescence of the photobacteria. At the same time, the magnetic field did not significantly affect either the concentration of oxygen or the concentration of bacterial cells in suspension, indicating a direct influence of magnetic fields on the metabolic processes associated with the bioluminescent system of bacterial cells. During short-term exposure to this extremely low frequency magnetic field, we observed a burst of luminescence initiated by the active hydrodynamic stirring of the bacterial suspension. This resulted in slow but statistically significant increase in the intensity of baseline bioluminescence by 5-10%. Conclusion. P. phosphoreum is sensitive to the action of static and extremely low-frequency fields, showing a biological efficiency within 15% of the control values. This bacterial model of magnetosensitivity is convenient for further experimental verification of the hypothesis regarding the magnetosensitivity of radical pairs. The work was supported by IEEE “Magnetism in Ukraine 2022/2023 initiative”, project “Development of a microbial test to evaluate the effect of geomagnetic field on biological systems”. Grant Agreement #99184