Environmental pollution from waste and synthetic dyes poses a major problem for ecosystems and the health of living beings due to their carcinogenic and mutagenic effects. Therefore, the main aim of the present study was to evaluate the degradation of the methylene blue dye by the actinobacterial strain, Streptomyces sp. SY-BS5 and the optimization of degradation parameters. Experiments included the determination of decolorization rate using the one-factor-at-a-time method. Then the optimization of decolorization with Response Surface Methodology (RSM) by Box-Behncken Design (BBD), including three parameters with three values (-1, 0 and +1), namely the initial methylene blue dye concentration (5 mg/L, 15 mg/L and 25 mg/L), the temperature (28°C, 32°C and 37°C) and the incubation time (24h, 48h and 72h). The optimization results showed a decolorization rate of 50.84% at an initial dye concentration of 25 mg/L, a temperature of 37°C, and an incubation time of 48 h. The RSM improved the degradation conditions of the methylene blue dye by the actinobacterial strain. The results obtained in the present study demonstrate the biodegradation potential of the actinobacterial strains and their suitability for the biodegradation of synthetic dyes.
Data from screening studies on the spread of African swine fever (ASF) in shot wild boars for the seven years (2019 - 2025) were summarized and analyzed. A total of 28 194 blood samples were tested for ASF virus genome by real-time polymerase chain reaction (PCR) and for antibodies against ASF virus by enzyme-linked immunosorbent assay (ELISA). Data from the acute phase of the epizootic were compared with the later stages of its development. Fifty-two cases of positive samples for the virus genome were identified. Of the wild boars shot during the period, only 5.2% had antibodies against the ASF virus. The results obtained show the resistance of the virus in the wild boar population and its persistence at reduced virulence, which makes the fight against the disease even more complicated.
Increasing antibiotic resistance poses a serious threat to human and animal health, as well as to the well-being of the environment. The present study aimed to quantify the total enterococci and those resistant to five classes of antibiotics in the water of an urban stretch of the Yantra River, Bulgaria. Phenotypic and genotypic antibiotic resistance patterns of primary selected antibiotic-resistant enterococci were assessed by the disk diffusion method and PCR assays. In the urban river stretch, the total number and relative proportion of antibiotic-resistant enterococci depended on the water sampling point. The dynamics of the population density of enterococci and their associated antibiotic resistance along the river stretch indicated anthropogenic impact on water quality. Riverine Enterococcus spp. isolates showed high levels of multidrug resistance to ampicillin, erythromycin, ciprofloxacin, tetracycline, and high-level gentamicin, as well as phenotypic patterns similar to those in clinical isolates and isolates from untreated wastewater. Waterborne enterococci are a reliable indicator of the prevalence of antibiotic resistance in the waters of the Yantra River, reflecting anthropogenic impact and potential risk to human health associated with their intended use.
Microbial resistance represents one of the most pressing challenges in contemporary medicine and biotechnology, driving the ongoing search for novel bioactive compounds with unique antimicrobial properties. Extreme environments and their associated extremophilic microorganisms constitute a promising reservoir of such metabolites. Among them, Antarctic filamentous fungi have evolved specialized adaptive strategies that enable survival under severe environmental constraints, including the biosynthesis of structurally diverse bioactive molecules. The present study investigates the potential of filamentous fungi isolated from soil samples collected on Livingston Island, Antarctica, to produce antibacterial metabolites. Notably, 75% of the tested strains exhibited antibacterial activity. The most active isolate was identified as Talaromyces pinophilus II 13. Metabolomic profiling suggested the presence of β-lactam-related metabolites and other antimicrobial secondary metabolites, underscoring its considerable biotechnological and pharmaceutical potential.
Spontaneous fermentation of fruit beverages involves complex microbial interactions in which indigenous yeasts play a key role in aroma formation, fermentation dynamics, and overall product quality. The present study aimed to isolate and identify yeast strains from spontaneously fermented low-alcohol fruit beverages prepared from wild-growing fruits according to a traditional recipe from the Rhodope region of Bulgaria. Four beverages containing lingonberry, chokeberry, rosehip, hawthorn, elderberry, and wild apple fruits were fermented under ambient conditions for approximately 30 days. The isolates were cultivated on YPD broth and YPD agar media and characterized by cell and colony morphology. Distinct species-specific morphological characteristics were observed among the isolates. Molecular identification was performed using PCR amplification and sequencing of the 18S or internal transcribed spacer (ITS) rDNA gene region, followed by BLASTn analysis against reference sequences in the NCBI GenBank database. Three yeast species were isolated and identified: Kregervanrija delftensis, Pichia membranifaciens, and Saccharomyces bayanus, showing 99–100 % pairwise similarity with corresponding reference strains. The results obtained could help to expand current knowledge regarding yeast diversity in spontaneously fermented fruit beverages from regional wild fruits and demonstrate the presence of indigenous non-Saccharomyces and Saccharomyces yeasts with potential applications in beverage biotechnology and fermentation processes.
