Appl. Microbiol., Volume 5, Issue 3 (September 2025) – 45 articles

Asparaginase (ASNase) is an important enzyme used to treat acute lymphoblastic leukemia. However, the clinical use of the currently available ASNases is limited because of their associated side effects. One of the major reasons for these adverse effects is the coactivity of glutaminase (GLNase) with ASNase. Furthermore, the concomitant urease activity may exacerbate the toxicity associated with ASNase treatment. Therefore, identifying novel sources of ASNase with minimal or no glutaminase and urease activities is important. We isolated a marine fungal strain, MABIK FU00000820, which produced ASNase free of GLNase and urease activity. Based on morphological and phylogenetic analyses, this strain was identified as Paraconiothyrium cyclothyrioides. The crude extract of intracellular ASNase exhibited the maximum activity at 37–50 °C, pH 8.5, and 0% (w/v) NaCl. In addition, the enzyme stability assay showed that the P. cyclothyrioides ASNase pre-treated at 4–25 °C for 2 h retained 77% of its activity compared to the untreated control. Based on the available literature, this appears to be the first study to investigate ASNase from P. cyclothyrioides, and it is of particular significance because the enzyme exhibits neither GLNase nor urease activity. Full article

Aflatoxin contamination of animal feeds may impact broiler chicken health and production. The adverse impact of aflatoxin can be ameliorated and detoxified by adding capable binding agents, such as Saccharomyces cerevisiae. A total of 648 mixed gender 1-day-old Ross-308 were assigned to a 3 × 2 factorial experiment to investigate the effect of aflatoxin B1 (AF) and Saccharomyces cerevisiae (SAC) on growth performance, blood parameters and carcass characteristics. Chickens were randomly allocated to dietary treatments consisting of three levels of AF at 0, 20 and 60 µg/kg, and with or without SAC (10¹⁰ cells/kg) supplementation of 1 g/kg of dried yeast. Results showed that both AF and SAC increased average daily feed intake (both, p < 0.001) and reduced feed efficiency (p < 0.001 and p = 0.035, respectively), while only AF reduced average daily gain (p = 0.009). Supplementation with SAC improved the average daily feed intake in chickens subjected to AF60 (interaction, p < 0.001), suggesting that SAC could improve the appetite of broilers. Chickens fed AF had a lower carcass weight (p = 0.028) and heart weight (p = 0.031), but higher carcass-normalized weight of gizzard (p = 0.038) and liver (p = 0.010). Aflatoxin administration reduced white blood cells (p = 0.030), lymphocytes (p = 0.029) and basophils (p < 0.001), while increasing neutrophils (p = 0.009). SAC reduced neutrophils (p = 0.004) and mean corpuscular haemoglobin (p < 0.001) while increasing lymphocytes (p = 0.003) and basophils (p = 0.015). The haematological results suggest that AF caused a disturbance in the immune system, compromising the health of the chicken, whereas SAC potentially mitigates these alterations. Dietary AF increased the activity of glutamate oxaloacetate transaminase (p = 0.009). These findings suggest a potential use of Saccharomyces cerevisiae as a natural binder to reduce aflatoxicosis in poultry production systems. Full article

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is an important therapeutic cytokine. Methylotrophic yeasts such as Komagataella phaffii and Ogataea parapolymorpha are attractive hosts for recombinant protein production. In this study, these yeasts were engineered to produce GM-CSF in both secreted and cell-surface-anchored forms. Secreted GM-CSF accumulated to tens of milligrams per liter in culture supernatants following induction. Fluorescent antibody labeling confirmed that yeast strains expressing surface-displayed GM-CSF exhibited markedly increased fluorescence compared to parental strains. The highest signal was observed in K. phaffii and further validated by immunofluorescence microscopy. Functional assays demonstrated that K. phaffii cells displaying GM-CSF stimulated TF-1 cell proliferation 1.41-fold compared to control yeast lacking GM-CSF. These results confirm both the successful surface display and preserved biological activity of the cytokine. This work demonstrates the feasibility of engineering K. phaffii to present active human GM-CSF on the cell surface. Surface display was efficient and yielded biologically functional cytokine, as shown by fluorescence-based quantification and TF-1 proliferation assays. The study highlights yeast surface display as a promising platform for delivering therapeutic cytokines without requiring purification steps. Full article

This work was undertaken in order to identify the presence of changes in the characteristics of poly(vinyl alcohol) (PVA) cryogels that can contribute to the degradation of such polymer matrices under the influence of their contact with various microorganisms used in immobilized form in different biotechnological processes using various complex media and conditions. Immobilized cells of bacteria, yeasts, microalgae, fungi, and microbial consortia were involved in the investigations. It was established that the presence of microorganisms can indirectly (through media transformed by them, in particular, containing lipids) or directly (through high rates of metabolite production, in particular, the fast accumulation of gases in the pores of polymer matrices, or due to the colonization of cryogels (self)immobilization by fungi with the growing mycelium) decrease rheological characteristics of PVA cryogel. Such weakening of PVA cryogels can be expected as a result of the first stage of further degradation of polymer matrices. The values of both the modulus of elasticity and the shear modulus of PVA cryogels confirmed this. The effect of high pressure accumulated in the reactors with PVA cryogel-immobilized cells, as well as their use in flow systems, was not revealed. These factors can be taken into account for the sustainable use of matrices based on PVA cryogels as biocatalysts with microorganisms or soil-structuring elements in artificial or natural environments. Full article

Air pollution remains one of the most urgent global challenges, affecting both public health and environmental integrity, with its severity escalating in parallel with industrialization and urban expansion. Defined as the presence of harmful substances in the atmosphere, air pollution poses risks to human health and disrupts the development of plant and animal life. Urban areas, particularly large cities, frequently exhibit pollutant concentrations that exceed safety thresholds established by the World Health Organization (WHO). This study presents a comprehensive analysis of airborne fungal microbiota in two distinct districts of Sofia, Bulgaria: the highly urbanized city center (Orlov Most) and a less urbanized southwestern area (New Bulgarian University, Ovcha Kupel). Weekly fluctuations in mold spore abundance were monitored, revealing elevated contamination levels on Fridays, likely due to intensified vehicular traffic preceding weekends and public holidays. Taxonomic identification of dominant mold species was conducted using both classical and molecular genetic methods. The isolated fungal strains predominantly belonged to the phylum Ascomycota (80%), with Talaromyces and Alternaria emerging as the most prevalent genera. Additionally, antifungal susceptibility testing indicated that most isolates were sensitive to commonly used antifungal agents, although resistance was observed in two strains of Talaromyces wortmannii. These findings underscore the significance of fungal bioaerosols in urban air quality assessments and highlight the need for targeted monitoring and mitigation strategies. Full article

Valorisation of spent yeast biomass post-fermentation requires energy-intensive autolysis or enzymatic hydrolysis that reduces the net benefit. Here, we present a simple and reproducible method for generating functional yeast extract recycled from Komagataella phaffii biomass without a requirement of a pre-treatment process. Spent yeast pellets from fermentations were freeze-dried to produce a fine powder that can be used directly at low concentrations, 0.0015% (w/v), together with 2% peptone (w/v), to formulate complete media ready for secondary fermentations. This media formulation supported growth rates of yeast culture that were statistically indistinguishable (p-value > 0.05) from cultures grown in standard YPD media containing commercial yeast extract, and these cultures produced equivalent titres of recombinant β-glucosidase (0.998 Abs_405nm commercial extract vs. 0.899 Abs_405nm recycled extract). Additionally, nutrient analyses highlight equivalent levels of sugars (~23 g/L), total proteins, and cell yield per carbon source (~2.17 g) with this recycled yeast extract media formulation when compared to commercial media. This method reduces process complexity and cost and enables the circular reuse of yeast biomass. The protocol is technically straightforward to implement, using freeze drying that is commonly available in research laboratories, representing a broadly applicable and sustainable alternative to conventional media supplementation that achieves a circular approach within the same fermentation system. Full article

The phyllosphere, the aerial part of plants, serves as a crucial habitat for diverse microorganisms. Phyllosphere bacteria can activate protective mechanisms that help plants resist disease. This study focuses on isolating and characterizing phyllosphere bacteria from cucurbits to evaluate their potential in controlling Colletotrichum orbiculare, a pathogen causing anthracnose in cucumbers. Among the 76 bacterial isolates collected, 11 exhibited strong antagonistic effects against C. orbiculare in vitro. Morphological and 16S rRNA analyses identified these isolates as different Bacillus species, including B. vallismortis, B. velezensis, B. amyloliquefaciens, and B. subtilis. These bacteria demonstrated essential plant-growth-promoting and biocontrol traits, such as motility, biofilm formation, phosphate solubilization, nitrogen fixation, and the production of indole acetic acid. Most of the bacterial strains also produced biocontrol compounds such as ammonia, acetoin, siderophores, hydrogen cyanide, chitinase, protease, lipase, and cellulase. The application of these bacteria significantly enhanced cucumber growth in both non-manured and organically manured soils, showing improvements in root and shoot length, chlorophyll content, and biomass accumulation. Additionally, bacterial treatments effectively reduced anthracnose severity, with isolates GL-10 and L-1 showing the highest disease suppression in both soil types. Colonization studies showed that phyllobacteria preferentially colonized healthy leaves over roots and diseased tissues, and they were more effective in manure-amended soils. These results suggest that Bacillus phyllobacteria have strong potential as sustainable bio-stimulants and biocontrol agents, offering an effective approach for enhancing cucumber growth and disease control under both fertilized and unfertilized soil conditions. Full article

This study evaluates the effects of two Trichoderma reesei exogenous fibrolytic enzyme (EFE) preparations on the taxonomic profile, diversity, relative abundance, and population shifts of three ruminal bacteria fractions of lactating cows: free-floating (LIQ), weakly (AS), and tightly (SOL) feed-adhered. Three lactating cows were fed three EFE treatments in a 3 × 3 Latin square design: one control (CON) without enzymes, a cellulase/xylanase mix (MIX), and a high-xylanase treatment (XYL). Rumen contents were collected, and bacteria were extracted from the three ruminal content fractions for next-generation sequencing analysis. Alpha diversity was higher in XYL compared to CON. However, no EFE effect was observed on beta diversity. The relative abundance (RA) of the family Prevotellaceae increased, while that of Ruminococcaceae and Rikenellaceae decreased in XYL compared to MIX and CON. The bacterial community structure (beta diversity) of LIQ was differentiated from that of SOL and AS (p = 0.03), but no effects of fraction were observed on alpha diversity. Lachnospiraceae RA was greater in SOL, followed by AS, and lower in LIQ (p < 0.001), while Spirochaetaceae RA was greater in SOL and AS compared to LIQ (p = 0.003). The effects of EFE supplementation on rumen bacterial RA were independent of the ruminal content fraction. Full article

Bacterial cellulose (BC), a nanostructured biopolymer produced by Komagateibacter spp., exhibits remarkable mechanical strength, purity, and biocompatibility, making it highly attractive for applications in biomedicine, food, and sustainable materials. Despite its potential, monoculture fermentation suffers from low yield and limited scalability. This review highlights the innovative application of co-culture fermentations as a novel strategy, where Komagataeibacter is paired with complementary microorganisms such as yeasts, lactic acid bacteria, and photosynthetic microbes. This approach has emerged as a promising solution to overcome the limitations of monoculture by enhancing BC productivity, tailoring material properties, and improving sustainability. We explore the synergistic interactions within co-cultures, including metabolic cross-feeding and in situ polymer integration, while also addressing critical challenges such as microbial stability and operational complexity. Unlike previous reviews focused primarily on BC biosynthesis, applications, or genetic engineering, this article emphasizes co-culture fermentation with Komagataeibacter as a novel and underexplored strategy to improve the yield, functionality, and scalability of BC production. Full article

Iron is a limiting factor for plant and microbial growth because, in soil environments, it is predominantly present as oxyhydroxide minerals, rendering it unavailable to plants and microorganisms. Siderophores are chelating agents secreted to solubilize iron and facilitate its uptake. To understand the evolutionary and ecological dynamics of microbial communities, as well as the evolution of pathogens within hosts, it is essential to study the genes shared between microorganisms for environmental adaptation and survival. In this study, we conducted microbiological assays to evaluate the effect of the siderophore produced by Rouxiella badensis strain SER3 on the mycelial growth of fungal pathogens such as Fusarium brachygibbosum 4BF. Using spectrophotometric techniques and bioinformatics tools, we identified desferrioxamine E (nocardamine) in the culture supernatant, and the corresponding biosynthetic gene cluster in the SER3 genome was confirmed through antiSMASH analysis and synteny comparisons. Gene expression analysis by RT-PCR showed differential expression of biosynthetic precursors when strain SER3 was grown alone or in interaction with fungal pathogen. Finally, scanning electron microscopy revealed structural damage to F. brachygibbosum hyphae during co-culture with strain SER3. These results suggest that the production of desferrioxamine E may act as a biocontrol mechanism employed by R. badensis SER3 against F. brachygibbosum. Full article

Insect pests impose major economic, agricultural, and public health burdens, damaging crops and transmitting pathogens such as dengue, malaria, and Zika. Conventional chemical control is increasingly ineffective due to insecticide resistance and environmental concerns, prompting a search for innovative strategies. The insect microbiome—comprising both obligate symbionts and environmentally acquired microbes—emerges as a key driver of host physiology and behavior. Microbes influence nutrient acquisition, immunity, reproduction, and chemosensory processing, often to promote their own transmission. By modulating olfactory and gustatory pathways, microbiota can alter host-seeking, mate choice, foraging, and oviposition patterns, reshaping ecological interactions and vector dynamics. These effects are shaped by microbial acquisition routes, habitat conditions, and anthropogenic pressures such as pesticide use, pollution, and climate change. Understanding these multi-directional interactions offers opportunities to design highly specific, microbe-based insect control strategies, from deploying microbial metabolites that disrupt host sensory systems to restoring beneficial symbionts in threatened pollinators. Integrating microbiome ecology with insect physiology and behavior not only deepens our understanding of host–microbe coevolution but also enables the development of sustainable, targeted alternatives to chemical insecticides. This review synthesizes current evidence linking microbiomes to insect biology and explores their potential as tools for pest and vector management. Full article

Pathogenic bacteria have developed different ways to cause infections. One strategy involves using components from host cells. This study looks at the role of the cytoskeleton in the human colon adenocarcinoma Caco-2 and neonatal non-transformed epithelial H4 cell lines during bacterial invasion. The bacteria studied include Cronobacter malonaticus, Cronobacter sakazakii, and E. coli K1, as they are associated with known diseases. Salmonella enteritidis 358 served as a positive control and E. coli K12 as a negative control for the invasion experiments. Before the invasion experiments, cell lines were treated with microfilament inhibitors, specifically Cytochalasin D, and microtubule inhibitors, such as Colchicine, Nocodazole, Vinblastine, and Taxol. The results showed that Cytochalasin D reduced about 60–80% of Cronobacter invasion into H4 cells and 50% of E. coli K1 invasion. In contrast, Colchicine reduced the invasion of some strains to just 2% compared to untreated cells. Meanwhile, Nocodazole and Taxol increased the invasion of C. sakazakii 709 and C. malonaticus 1569 into H4 cells by about 140% and 160%, respectively, while slightly inhibiting other strains. In Caco-2 cells, certain strains exhibited increased invasion due to Cytochalasin D, Vinblastine, and Colchicine treatment. This led to increases of up to 500%, 227%, and 248% compared to untreated cells. However, Nocodazole and Taxol decreased invasion into Caco-2 cells, with only E. coli K1 showing an increase of about 150% in Taxol-treated cells. The findings with eukaryotic cytoskeleton inhibitors on neonatal H4 cells suggest that bacterial invasion mainly relies on microfilaments or microfilament-dependent. No specific dependence on the cytoskeleton was seen in Caco-2 cells. In conclusion, cytoskeletal inhibitors significantly affected bacterial invasion, specifically Cronobacter, compared to untreated cells. This suggests that invasion methods may vary by strain and are influenced by how each inhibitor alters cytoskeleton behavior. Therefore, the invasion process, both with and without cytoskeletal inhibitors, is crucial for understanding how bacteria manipulate cell components during infection. Full article

In the case of a notifiable animal disease like salmonellosis, manure is contaminated and must be disinfected. This can be performed using heat measures, chemical disinfectants, or long-term storage. All these measures bring along severe economic, ecological, and logistical problems. The aim of this study was to evaluate lactic acid fermentation (LAF) as an alternative disinfection method. Fermentation was started by adding a carbohydrate source to the manure and creating anaerobic conditions. For testing, cattle manure was enriched with different carbohydrate (CHO) sources and spiked with Salmonella Typhimurium (S. Ty.). The samples were incubated at 10 °C and 21 °C for 111 days (Exp1) and at 21 °C for 50 days (Exp2). The microbial shift was determined using cultural methods and MALDI-TOF. Both the change in pH and Enterococcus spp. were tested as suitable indicators. The results showed the different suitability of the selected CHO for hygienization by LAF. Using squeezed oat as an additive, S. Ty was reduced to below the detection limit under both temperature conditions within 21 days and 14 days. Additional saccharose decreased the reduction time. This study showed that LAF is a valuable alternative for disinfecting cattle manure in the case of bovine salmonellosis. Using this method, both manure and feed residues can be treated in one approach and afterwards be used as fertilizer. Full article

Escherichia coli O157:H7 has been an important foodborne pathogen causing severe disease in humans worldwide. It is challenging to control E. coli O157:H7 due to its intrinsic acid resistance, ability to survive in various environments, and the emergence of antimicrobial resistance. Recent research showed that phages are promising antibacterial agents. A phage (Φ241) infecting 48 E. coli O157:H7 strains from various sources was previously isolated from an industrial cucumber fermentation at pH 3.7 and 5% NaCl. The efficacy of phage Φ241 infection was evaluated in this study in four representative model food systems (beef broth, cucumber juice, cucumber juice supplemented with NaCl, and apple juice). Pronounced differences in phage effectiveness were found in the tested food systems, and impacted by pH, salinity, and multiplicity of infection. The potential of this phage is evident in beef broth and cucumber juice, where 4- to 6-log reduction in host concentration was achieved within 3 to 5 h. However, apple juice (pH 3.55) completely inhibited host growth and phage infection. Overall, the study shows the high potential of Φ241 as an antibacterial agent to improve food safety. Future research will incorporate a cocktail of phages targeting E. coli O157:H7 to mitigate phage resistance development. Full article

Coffee pulp, the primary residue generated during the wet processing of Coffea arabica L., is frequently applied directly to fields as a crude soil amendment. However, this practice often lacks proper microbial stabilization, limiting its agronomic potential and posing risks due to the presence of phytotoxic compounds. In Colombia, disease-resistant varieties such as Coffea arabica L. var. Castillo and var. Cenicafé 1, developed by the National Coffee Research Center (Cenicafé), are the amongst the most widely cultivated varieties in the country; however, despite their widespread adoption, the microbial ecology of postharvest residues from these varieties remains poorly characterized. This study aimed to isolate and functionally characterize native microbial communities from the pulp of Coffea arabica var. Castillo and var. Cenicafé 1, and to evaluate their role in postharvest processing and organic waste management. Fresh pulp samples were collected from a wet-processing facility located in tropical mid-elevation zones. A total of 53 microbial isolates were recovered using culture-dependent techniques on selective media targeting yeasts, lactic acid bacteria (LAB), and filamentous fungi. Amplicon sequencing of the 16S rRNA gene (V3–V4 region) and ITS1 region was conducted to profile bacterial and fungal communities, revealing diverse microbial consortia dominated by Aspergillus, Lactobacillus, Leuconostoc, Pichia, and Saccharomyces species. Enzymatic screening indicated high pectinolytic and cellulolytic activity. Composting trials using inoculated pulp showed a ~40% reduction in composting time and improved nutrient content. These findings support the use of native microbiota to enhance composting efficiency and postharvest valorization, contributing to more sustainable and circular coffee systems. Full article

Myxobacteria, a group of swarming, predatory soil bacteria, are of interest because of their biocontrol potential. In this study, the inhibitory effects of 13 strains of myxobacteria were examined against four different phytopathogenic fungi, as follows: two isolates of Rhizoctonia solani from different AG groups and one isolate each from Sclerotinia sclerotiorum and the oomycete Pythium ultimum. Inhibition levels varied among phytopathogens, with slow-growers being more susceptible than fast-growers. Myxococcus xanthus BS 248, M. flavus ATCC 29617, and M. coralloides BS249 were the most inhibitory strains tested. non-contact and contact inhibition on agar media between phytopathogens and myxobacteria were visually discernible. This distinction potentially reflects the activity of low-molecular-weight metabolites and high-molecular-weight lytic enzymes, respectively. In a pot soil study, the inhibitory effect of a mixture of two strains of myxobacteria against two strains of R. solani was apparent from the reduced disease in cucumber seedlings compared to controls without myxobacteria. This is the first report of an in vivo inhibitory effect of myxobacteria against Rhizoctonia. The survival of M. xanthus BS248 in sterile soil amended with rabbit manure (1:1) increased up to five weeks compared to one week in soil without the manure, suggesting that organic amendment could enrich myxobacteria in soil. Full article

Microbial metabolites offer a multitude of mechanisms for alleviating diabetes, particularly type 2 diabetes (T2D). However, the metabolites of yeasts recognised as safe remain under-explored and are receiving less attention in the treatment of T2D. In addition to the recognised probiotic status of certain yeasts, their genetic feature is responsible for many of the effects observed. Branched and non-branched short-chain fatty acids, bioactive peptides, carotenoids, and polysaccharides (β-glucans, mannans, and peptides derived from them) have vital properties that modulate intestinal permeability, soothe inflammation, and directly influence insulin sensitivity. Their action mechanism ranges from hepatic lipogenesis via the induction of hormone-sensitive lipase and the inhibition of α-glucosidase or DPP-IV to promoting the secretion of GLP-1 (Glucagon-Like Peptide-1) and GIP (Gastric Inhibitory Polypeptide), orchestrating immune modulation, and nourishing the gut microbiota. The richness of the yeast metabolome suggests that a concentrated fermentate could be developed to potentiate the functional effects in vitro in the treatment of T2D. The purpose of this review is to take stock of the current state of knowledge of probiotic yeast metabolites and outline their potential for the treatment of diabetes via the development of food supplements or nutraceuticals. Full article

Veterinary vaccines are essential tools for controlling infectious and zoonotic diseases, safeguarding animal welfare, and ensuring global food security. However, conventional vaccines are hindered by cold-chain dependence, thermal instability, and logistical challenges, particularly in low- and middle-income countries (LMICs). This review explores next-generation veterinary vaccines, emphasizing innovations in thermostability and delivery platforms to overcome these barriers. Recent advances in vaccine drying technologies, such as lyophilization and spray drying, have improved antigen stability and storage resilience, facilitating effective immunization in remote settings. Additionally, novel delivery systems, including nanoparticle-based formulations, microneedles, and mucosal routes (intranasal, aerosol, and oral), enhance vaccine efficacy, targeting immune responses at mucosal surfaces while minimizing invasiveness and cost. These approaches reduce reliance on cold-chain logistics, improve vaccine uptake, and enable large-scale deployment in field conditions. The integration of thermostable formulations with innovative delivery technologies offers scalable solutions to immunize livestock and aquatic species against major pathogens. Moreover, these strategies contribute significantly to One Health objectives by mitigating zoonotic spillovers, reducing antibiotic reliance, and supporting sustainable development through improved animal productivity. The emerging role of artificial intelligence (AI) in vaccine design—facilitating epitope prediction, formulation optimization, and rapid diagnostics—further accelerates vaccine innovation, particularly in resource-constrained environments. Collectively, the convergence of thermostability, advanced delivery systems, and AI-driven tools represents a transformative shift in veterinary vaccinology, with profound implications for public health, food systems, and global pandemic preparedness. Full article

Due to its high bioconversion efficiency and nutritional value, the black soldier fly (Hermetia illucens L. 1758) is a promising insect species for sustainable animal feed production. However, concerns remain regarding microbial safety when larvae are reared on substrates contaminated by pathogenic or spoilage bacteria. This study investigated the effects of substrate inoculation with Bacillus subtilis 168 or Pseudomonas putida KT2440 on larval performance and gut microbiota composition. Larvae reared on contaminated diets showed no significant differences in survival or development time compared to controls. However, a short-term reduction in growth was observed in the Bacillus-exposed group. qPCR analyses confirmed the temporary presence of Bacillus taxa in larval guts, while Pseudomonas taxa were effectively excluded. Amplicon sequencing of the 16S rRNA gene revealed that the contamination did not affect gut bacterial microbiota richness and composition. Instead, the bacterial communities evolved naturally with Lactobacillales-related bacteria dominating early stages and Morganellaceae taxa becoming more abundant in prepupae. Our findings demonstrate the stability and resilience of H. illucens gut bacterial microbiota, reinforcing the safety and suitability of H. illucens as a feed ingredient, even when reared under challenging microbial conditions. Full article

Salmonella is a zoonotic foodborne pathogen that affects poultry health and reaches consumers through the food chain via contaminated products. A cross-sectional study was conducted to isolate and identify Salmonella and to detect antibiotic resistance genes in Salmonella isolates from retail meat shops in Chitwan, Nepal. The antimicrobial susceptibility test was carried out using the Kirby–Bauer disc diffusion method. Antibiotic resistance genes were detected by using multiplex polymerase chain reaction (PCR). A total of 216 samples, chicken meat (108) and water (108), were tested for the presence of Salmonella. Out of the 216 samples tested, 38 samples were positive, giving an overall prevalence of 17.59%. A higher prevalence of Salmonella was found in meat samples, 29.62% (32/108), compared with the water samples, 5.55% (6/108), which was statistically significant (p < 0.05). The antibiogram profile showed maximum resistance to doxycycline (88%), followed by tetracycline (86%), erythromycin (79%), ampicillin + sulbactam (76%), ceftriaxone (22%), levofloxacin (21%), gentamicin (18%), chloramphenicol (13%), and amikacin (15%). The prevalence of the tetB gene and ere(A) gene was 23.68% (9/38) and 18.42% (7/38), respectively, and the association was statistically non-significant (p > 0.05). However, mcr1, catA1, and blaTEM genes were not detected. The study recommends integrated surveillance encompassing human health, food safety, and animal health under the ‘One Health’ approach, highlighting the need for effective strategies involving poultry farms, retail meat shops, and consumers to minimize contamination and reduce the transmission of Salmonella along the food chain from primary production to consumption on a global scale. Full article

Foodborne illness caused by bacterial pathogens is a global health concern and results in millions of infections annually. Therefore, food products typically undergo several processing stages, including sanitation steps, before being distributed in an attempt to remove pathogens. However, many sanitation methods have compounding effects on the color, texture, flavor, and nutritional quality of the product or do not effectively reduce the pathogens that food can be exposed to. Some bacterial pathogens particularly possess traits and tactics that make them even more difficult to mitigate such as biofilm formation. Non-thermal plasma sanitation techniques, including plasma-treated water (PTW), have proven to be promising methods that significantly reduce pathogenic bacteria that food is exposed to. Published work reveals that PTW can effectively mitigate both gram-positive and gram-negative bacterial biofilms. This study presents a novel analysis of the differences in antimicrobial effects of PTW treatment between biofilm-forming gram-positive bacteria, commonly associated with foodborne illness, that are sporulating (Bacillus cereus) and non-sporulating (Listeria monocytogenes). After treatment with PTW, the results suggest the following hypotheses: (1) that the non-sporulating species experiences less membrane damage but a greater reduction in metabolic activity, leading to a possible viable but non-culturable (VBNC) state, and (2) that the sporulating species undergoes spore formation, which may subsequently convert into vegetative cells over time. PTW treatment on gram-positive bacterial biofilms that persist in food processing environments proves to be effective in reducing the proliferating abilities of the bacteria. However, the variance in PTW’s effects on metabolic activity and cell vitality between sporulating and non-sporulating species suggest that other survival tactics might be induced. This analysis further informs the application of PTW in food processing as an effective sanitation method. Full article

Heavy metal pollution represents a pervasive environmental challenge that significantly exacerbates the ever-increasing crisis of antimicrobial resistance and the capacity of microorganisms to endure and proliferate despite antibiotic interventions. This review examines the intricate relationship between heavy metals and AMR, with an emphasis on the underlying molecular mechanisms and ecological ramifications. Common environmental metals, including arsenic, mercury, cadmium, and lead, exert substantial selective pressures on microbial communities. These induce oxidative stress and DNA damage, potentially leading to mutations that enhance antibiotic resistance. Key microbial responses include the overexpression of efflux pumps that expel both metals and antibiotics, production of detoxifying enzymes, and formation of protective biofilms, all of which contribute to the emergence of multidrug-resistant strains. In the soil environment, particularly the rhizosphere, heavy metals disrupt plant–microbe interactions by inhibiting beneficial organisms, such as rhizobacteria, mycorrhizal fungi, and actinomycetes, thereby impairing nutrient cycling and plant health. Nonetheless, certain microbial consortia can tolerate and detoxify heavy metals through sequestration and biotransformation, rendering them valuable for bioremediation. Advances in biotechnology, including gene editing and the development of engineered metal-resistant microbes, offer promising solutions for mitigating the spread of metal-driven AMR and restoring ecological balance. By understanding the interplay between metal pollution and microbial resistance, we can more effectively devise strategies for environmental protection and public health. Full article

Background: Developments in biology, genetics, soil science, plant breeding, engineering, and agricultural microbiology are driving advances in soil microbiology and microbial biotechnology. Material and methods: The literature for this review was collected by searching leading scientific databases such as Embase, Medline/PubMed, Scopus, and Web of Science. Results: Recent advances in soil microbiology and biotechnology are discussed, emphasizing the role of microorganisms in sustainable agriculture. It has been shown that soil and plant microbiomes significantly contribute to improving soil fertility and plant and soil health. Microbes promote plant growth through various mechanisms, including potassium, phosphorus, and zinc solubilization, biological nitrogen fixation, production of ammonia, HCN, siderophores, and other secondary metabolites with antagonistic effects. The diversity of microbiomes related to crops, plant protection, and the environment is analyzed, as well as their role in improving food quality, especially under stress conditions. Particular attention was paid to the diversity of microbiomes and their mechanisms supporting plant growth and soil fertility. Conclusions: The key role of soil microorganisms in sustainable agriculture was highlighted. They can support the production of natural substances used as plant protection products, as well as biopesticides, bioregulators, or biofertilizers. Microbial biotechnology also offers potential in the production of sustainable chemicals, such as biofuels or biodegradable plastics (PHA) from plant sugars, and in the production of pharmaceuticals, including antibiotics, hormones, or enzymes. Full article

Sustainability represents a significant global challenge, requiring a balance between environmental impact and the use of natural resources. White biotechnology, which uses microorganisms and enzymes for environmentally friendly products and processes, offers promising solutions to support a growing population. Within this context, the yeast Yarrowia lipolytica stands out, so we investigated the generation of biomass from two wild strains (ATCC 9773 and NRRL Y-50997) using different carbon sources. Additionally, protein content and amino acid profiles were assessed via standardized analytical methods to evaluate their potential as nutritional yeasts. Both strains demonstrated potential as nutritional yeasts, with biomass productivities of up to 35.5 g/L and 42 g/L, respectively. The protein content was high, with 58.8% for ATCC 9773 and 58.2% for NRRL Y-50997. Furthermore, the strains presented essential amino acid contents of 62.6% and 41.5%, with lysine being the most abundant amino acid. These findings underscore the versatility and productivity of Y. lipolytica, highlighting its potential for sustainable biotechnological applications such as single-cell protein production. Full article

The study aimed to identify potential sources of novel probiotic yeasts exhibiting health-promoting properties. A combination of metabarcoding analysis and cultural methods was employed to investigate and isolate yeasts from various sources, including rice wine, palm wine, fermented shrimp paste at different stages of natural fermentation, and lychee peels. The two analytical methods revealed distinct yeast profiles, and each source exhibited a unique composition of yeast species. Through metabarcoding and cultural methods, it was demonstrated that lychee peels harbored a greater diversity of genera compared to other sources. The evaluation of the probiotic properties of yeasts revealed that lychee peel yielded the highest proportion of isolates with potential probiotic activity (53.33%), followed by palm wine (25%), fermented shrimp paste (10%), and rice wine (9.09%). Moreover, yeast isolates with health-promoting properties as evaluated in this study, including Starmerella meliponinorum L12 and Pichia terricola L9 from lychee peels, demonstrated notable antioxidant activity and cholesterol-reducing properties, respectively. These findings represent the first report providing initial insights into the influence of yeast sources and serve as a guideline for the targeted selection of yeasts with specific probiotic and health-promoting attributes. Full article

This study aimed to evaluate the production of xylose reductase (XR), an enzyme responsible for converting xylose into xylitol, by Candida tropicalis ATCC 750 using hemicellulosic hydrolysate from cashew apple bagasse (CABHM) as a low-cost carbon source. The effects of temperature, aeration, and fluid dynamics on XR biosynthesis were also investigated. The highest XR production (1.53 U mL⁻¹) was achieved at 30 °C, with 8.3 g·L⁻¹ of xylitol produced by the yeast under microaerobic conditions, demonstrating that aeration and fluid dynamics are important factors in this process. Cellular metabolism and enzyme production decreased at temperatures above 35 °C. The maximum enzymatic activity was observed at pH 7.0 and 50 °C. XR is a heterodimeric protein with a molecular mass of approximately 30 kDa. These results indicate that CABHM is a promising substrate for XR production by C. tropicalis, contributing to the development of enzymatic bioprocesses for xylitol production from lignocellulosic biomass. This study also demonstrates the potential of agro-industrial residues as sustainable feedstocks in biorefineries, aligning with the principles of a circular bioeconomy. Full article

Sourdough fermentation, driven by the biochemical activity of lactic acid bacteria (LAB), presents a scientifically promising approach to addressing nutritional limitations in cereal-based staples. This review critically examines both the underlying mechanisms by which LAB enhance the nutritional profile of sourdough and the translational challenges in realizing these benefits. Key improvements explored include enhanced mineral bioavailability (e.g., up to 90% phytate reduction), improved protein digestibility, an attenuated glycemic response (GI ≈ 54 vs. ≈75 for conventional bread), and the generation of bioactive compounds. While in vitro and animal studies extensively demonstrate LAB’s potential to reshape nutrient profiles (e.g., phytate hydrolysis improving iron absorption, proteolysis releasing bioactive peptides), translating these effects into consistent human health outcomes proves complex. Significant challenges hinder this transition from laboratory to diet, including the limited bioavailability of LAB-derived metabolites, high strain variability, and sensitivity to fermentation conditions. Furthermore, interactions with the food matrix and host-specific factors, such as gut microbiota composition, contribute to inconsistent findings. This review highlights methodological gaps, particularly reliance on in vitro or animal models, and the lack of long-term, effective human trials. Although LAB hold significant promise for nutritional improvements in sourdough, translating these findings to validated human benefits necessitates continued efforts in mechanism-driven strain optimization, the standardization of fermentation processes, and rigorous human studies. Full article

The increasing threat of antimicrobial resistance (AMR), along with the limited availability of new lead compounds in the drug development pipeline, highlights the urgent need to discover antimicrobial agents with innovative mechanisms of action. In this regard, metal complexes offer a unique opportunity to access mechanisms distinct from those of conventional antibiotics. Although iron (Fe) is an essential element for all forms of life, including pathogenic bacteria, it also poses a serious risk of cytotoxicity due to its redox activity, which can trigger the production of reactive oxygen species (ROS) via the Fenton reaction. This review highlights recent advances in the development of iron-based antimicrobial agents that harness the toxicity resulting from dysregulated iron uptake, thereby inducing bacterial cell death through oxidative stress. These findings may guide the development of effective treatments for pathogenic infections and offer new perspectives on leveraging redox chemistry of iron to combat the growing threat of global bacterial resistance. Full article

Myocardial infarction (MI) is an inflammatory disease responsible for approximately 75% of sudden cardiac deaths. In this study, we aimed to evaluate the cardio-protective influence of microencapsulated probiotic and synbiotic dietary supplements in vivo and in molecular docking studies. MI was induced in rats with the injection of isoproterenol (i.p. 67 mg/kg). Plasma lipid profiles and the levels of oxidative stress markers, inflammatory markers, and cardiac enzymes were determined. The expression levels of MMP-7 and IL-1β in the heart muscle were measured. The impact of dietary supplements on fecal bacterial counts was evaluated across all rat groups. A histopathological examination of cardiac tissue was performed. The cardio-protective potential of cyanidin 3-diglucoside 5-glucoside and arabinoxylan was studied using molecular docking. The results demonstrate that all tested dietary supplements induced an improvement in all the biochemical parameters in association with an improvement in myocardial muscle tissue. The mRNA expression levels of MMP-7 and IL-1β were significantly downregulated by all dietary supplements. All dietary supplements increased the fecal counts of probiotic strains. In the molecular docking analysis, cyanidin 3-diglucoside 5-glucoside exhibited binding affinity values of −8.8 and −10 for lactate dehydrogenase (LDH) and Paraoxonase 1 (PON1), respectively. Arabinoxylan showed similar binding affinity (−8.8) for both LDH and PON1. Conclusion: Microencapsulated probiotic and synbiotic dietary supplements demonstrated notable cardio-protective influence in vivo and in molecular docking studies. These supplements may serve as promising candidates for the prevention of myocardial infarction. Full article

A fungal strain with comparably high chitosan yield was isolated from the Shivaganga hills and identified as Aspergillus versicolor AD07 through molecular characterization. Later, the strain was cultivated on Sabouraud Dextrose Broth (SDB) and wild jackfruit-based media to evaluate its potential for chitosan production. Among the various media formulations, the highest chitosan yield (178.40 ± 1.76 mg/L) was obtained from the jackfruit extract medium with added peptone and dextrose. The extracted chitosan was characterized through FTIR, XRD (reported a crystallinity index of 55%), TGA/DTG, and DSC analysis, confirming the presence of key functional groups and high thermal resistance. The extracted chitosan was fabricated into a sheet incorporated with 1% lemongrass oil; the sheet exhibited strong antibacterial activity against Escherichia coli (30 mm) and Bacillus megaterium (48 mm). The biodegradation studies reported a weight loss of 38.93 ± 0.51% after 50 days of soil burial. Further, the chitosan film was tested as a packaging material for paneer, demonstrating better preservation by maintaining nutritional quality and reducing microbial load over a 14-day storage period. These findings highlight the potential of A. versicolor AD07-derived chitosan, cultivated on a waste substrate medium, as a sustainable biopolymer for food packaging applications. Full article