Search Results (252)

To explore an industrial fermentation approach for traditional mung bean sour pulp, this study isolated core microorganisms including lactic acid bacteria and yeasts from naturally fermented samples and constructed a synthetic microbial community. The optimized community consisted of Lactiplantibacillus pentosus, Lactococcus garvieae, and Cyberlindnera jadinii at a ratio of 7:3:0.1 and was used to ferment cooked mung bean pulp with a material-to-water ratio of 1:8 and 1% sucrose addition. Under these conditions, the final product exhibited significantly higher levels of protein (4.55 mg/mL), flavonoids (0.10 mg/mL), polyphenols (0.11 mg/mL), and vitamin C (7.75 μg/mL) than traditionally fermented mung bean sour pulp, along with enhanced antioxidant activity. The analysis of organic acids, free amino acids, and volatile compounds showed that lactic acid was the main acid component, the bitter amino acid content was reduced, the volatile flavor compounds were more abundant, and the level of harmful compound dimethyl sulfide was significantly decreased. These results indicate that fermentation using a synthetic microbial community effectively improved the nutritional quality, flavor, and safety of mung bean sour pulp. Full article

Restricting the use of chemical pesticides in forestry requires the search for alternative solutions. These could be volatile organic compounds produced by three investigated species of bacteria (Bacillus amyloliquefaciens (ex Fukumoto) Priest, B. subtilis (Ehrenberg) Cohn and B. thuringiensis Berliner), which inhibit the growth of the pathogen F. oxysporum Schltdl. emend. Snyder & Hansen in forest nurseries. The highest inhibition of fungal growth (70%) was observed with B. amyloliquefaciens after 24 h of antagonism test, which had a higher content of carbonyl compounds (46.83 ± 8.41%) than B. subtilis (41.50 ± 6.45%) or B. thuringiensis (34.62 ± 4.77%). Only in the volatile emissions of B. amyloliquefaciens were 3-hydroxybutan-2-one, undecan-2-one, dodecan-5-one and tetradecan-5-one found. In contrast, the main components of the volatile emissions of F. oxysporum were chlorinated derivatives of benzaldehyde (e.g., 3,5-dichloro-4-methoxybenzaldehyde) and chlorinated derivatives of benzene (e.g., 1,4-dichloro-2,5-dimethoxybenzene), as well as carbonyl compounds (e.g., benzaldehyde) and alcohols (e.g., benzyl alcohol). Further compounds were found in the interactions between B. amyloliquefaciens and F. oxysporum (e.g., $\alpha$-cubebene, linalool, undecan-2-ol, decan-2-one and 2,6-dichloroanisole). Specific substances were found for B. amyloliquefaciens (limonene, nonan-2-ol, phenethyl alcohol, heptan-2-one and tridecan-2-one) and for F. oxysporum (propan-1-ol, propan-2-ol, heptan-2-one and tridecan-2-one). The amounts of volatile chemical compounds found in B. amyloliquefaciens or in the bacterium–fungus interaction can be used for further research to limit the pathogenic fungus. In the future, one should focus on the compounds that were found exclusively in interactions and whose content was higher than in isolated bacteria. In order to conquer an ecological niche, bacteria increase the production of secondary metabolites, including specific chemical compounds. The results presented are a prerequisite for creating an alternative solution or supplementing the currently used methods of plant protection against F. oxysporum. Understanding and applying the volatile organic compounds produced by bacteria can complement chemical plant protection against the pathogen, especially in greenhouses or tunnels where plants grow in conditions that favour fungal growth. Full article

Agresto is the unfermented juice traditionally obtained from boiled unripe grapes, typically using fruit that would otherwise be discarded, and enriched with spices, herbs, and fruit. In this study, the phenolic profile, antioxidant and antibacterial activity, and volatile organic compounds (VOCs) of Agresto produced from two grape varieties (Sangiovese, and Vermentino) harvested in Mount Amiata (Tuscany) were evaluated. Agresto from Vermentino showed a higher total phenolic content (TPC), 1.31 mg GAE/mL, as well as a greater total flavonoid and flavonol content and FRAP activity compared to Agresto from Sangiovese. The highest ORAC value was observed in Agresto from Vermentino, 41.01 mg TE/mL, compared to that from Sangiovese. TPC, flavonols, apocarotenes, sulfur derivatives, and non-terpene derivatives were positively correlated with antimicrobial activity against E. coli, FRAP, and ORAC. Overall, our results showed that grape variety significantly influences the chemical composition of Agresto, particularly in terms of both VOCs and phenolic compounds. The observed variations in phenolic composition also affected the antioxidant and antimicrobial activity of Agresto. These experimental findings clearly suggest the utmost importance of identifying the optimal chemical profile of “unripe grapes” used as raw material for Agresto production, considering both variety and the specific ripening degree achievable through vine green harvesting. Full article

Sixteen long-ripened, high-quality Cabrales cheeses from independent producers underwent a comprehensive biochemical and microbiological characterisation. Significant variations in total microbial counts and specific microbial groups were observed among the cheeses. A metataxonomic analysis identified 249 prokaryotic amplicon sequence variants (ASVs) and 99 eukaryotic ASVs, respectively, which were classified into 52 prokaryotic and 43 eukaryotic species. The predominant species included bacteria of the genera Tetragenococcus, Lactococcus (of which Lactococcus lactis was used as a starter), and Staphylococcus, followed by Brevibacterium and Corynebacterium species. The starter mould Penicillium roqueforti was highly abundant in all cheeses; Debaryomyces hansenii, Geotrichum candidum, and Kluyveromyces spp. constituted the subdominant fungal populations. Glutamic acid (≈20 mg g⁻¹) was the most abundant free amino acid in all samples, followed by lysine, leucine, and valine (≈10–13 mg g⁻¹). Moderate-to-high amounts of the biogenic amines tyramine and ornithine were detected. A large variation between cheeses of the main organic acids (lactic, acetic, or butyric) was detected. Differences between samples were also observed for the majority volatile compounds, which included organic acids, alcohols, esters, and ketones. Positive and negative correlations between bacterial and fungal species were detected, as well as between microbial populations and key biochemical markers. Among the latter, Tetragenococcus halophilus correlated positively with ethyl caprylate and hexanoic acid, and Loigolactobacillus rennini correlated positively with γ-aminobutyric acid. Conversely, Staphylococcus equorum showed a strong negative correlation with ethyl caprylate and capric acid. These microbial and biochemical insights enabled us to propose a microbiota-based starter culture comprising prokaryotic and eukaryotic components to enhance Cabrales cheese quality. Full article

This review presents information obtained over the past 10 years on the methods to control the widespread worldwide phytopathogen Pectobacterium carotovorum subsp. carotovorum (Pcc). This bacterium is among the ten most dangerous phytopathogens; it affects a wide range of cultivated plants: vegetables, ornamental and medicinal crops, both during vegetation and during the storage of fruits. Symptoms of Pcc damage include the wilting of plants, blackening of vessels on leaves, stems and petioles. At the flowering stage, the stem core gradually wilts and, starting from the root, the stem breaks and the plant dies. Pcc is a rod-shaped, non-capsule and endospore-forming facultative anaerobic Gram-negative bacterium with peritrichous flagellation. Pcc synthesizes bacteriocins—carocins. The main virulence factors of Pcc are the synthesis of N-acyl-homoserine lactone (AHL) and plant cell wall-degrading enzymes (PCWDEs) (pectinases, polygalacturonases, cellulases, and proteases). Diagnostic methods for this phytopathogen include polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), multilocus genotyping of strain-specific genes and detection of unique volatile organic compounds (VOCs). The main methods to control this microorganism include the use of various chemicals (acids, phenols, esters, salts, gases), plant extracts (from grasses, shrubs, trees, and algae), antagonistic bacteria (Bacillus, Pseudomonas, Streptomyces, and lactic acid bacteria), viruses (including a mixture of bacteriophages), and nanomaterials based on metals and chitosan. Full article

Kimchi, a traditional fermented product made primarily with Chinese cabbage, develops its characteristic flavor through microbial activity and a variety of ingredients. This study explores the incorporation of sea fennel (Crithmum maritimum L.), a halophytic plant rich in bioactive compounds and known for its distinctive aroma, into kimchi. Two fermentation methods were compared: spontaneous fermentation and fermentation using a defined starter culture of four lactic acid bacteria strains. Fermentation was conducted at 4 °C for 26 days, with samples monitored for up to 150 days. Parameters analyzed included pH, titratable acidity, microbial counts, organic acid concentrations, volatile organic compounds (VOCs), and sensory attributes. In the early stages, notable differences in acidity, microbial populations, and VOCs were observed between the two methods, but these differences diminished over time. Sensory analysis indicated similar overall characteristics for both prototypes, although the sea fennel’s aroma and fibrous texture remained perceptible at day 150. VOCs analysis revealed that the fermentation time significantly affected the composition of key aroma compounds, contributing to the final sensory profile. Sea fennel played a key role in shaping the VOC profile and imparting a distinctive aromatic quality. Both fermentation methods led to similar enhancements in flavor and product quality. These findings support the use of sea fennel as an aromatic ingredient in fermented vegetables and highlight the importance of fermentation optimization. Full article

Peanut root rot poses a significant threat to global peanut production. In order to identify the new pathogen of peanut root rot in Shandong province, China, and to screen the effective antagonistic biocontrol strains against the identified pathogen, ten symptomatic plants from a peanut field (10% disease incidence) of Rongcheng were sampled for pathogen isolation. The predominant isolate RC-103 was identified as Ceratobasidium sp. AG-A through morphological characterization and phylogenetic analysis of ITS and RPB2 sequences. Pathogenicity was confirmed via Koch’s postulates. Three potent biocontrol strains, namely Bacillus subtilis LY-1, Bacillus velezensis ZHX-7, and Burkholderia cepacia Bc-HN1, were screened for effective antagonism against isolate RC-103 by dual-culture analysis. Their cell suspensions could significantly inhibit the hyphal growth of isolate RC-103, with the percentage inhibition of 54.70%, 45.86%, and 48.62%, respectively. Notably, the percentage inhibition of 10% concentration of the cell-free culture filtrate of B. subtilis LY-1 was as high as 59.01%, and the inhibition rate of volatile organic compounds of B. cepacia Bc-HN1 was 48.62%. Antagonistic mechanisms primarily involved the induction of hyphal abnormalities. In addition, the culture filtrate of these biocontrol bacteria significantly promoted the growth of peanut and increased the resistance of peanut plants to isolate RC-103, with the biocontrol efficiency reaching 41.86%. In summary, this study identified a novel pathogen of peanut root rot, Ceratobasidium sp. AG-A, which was reported for the first time in China, and screened three highly effective antagonistic biocontrol strains against Ceratobasidium sp. AG-A isolate RC-103, providing the scientific basis to study the epidemiology and management of this disease. Full article

With the sustainable increase in agricultural productivity, the need for safer, environmentally friendly pesticide alternatives is also growing. Metabolites of microorganisms (bacteria, fungi, actinomycetes) are emerging as potential bioactive compounds for integrated pest and disease management. These compounds comprise amino acids, carbohydrates, lipids, organic acids, phenolics, peptides, alkaloids, polyketides, and volatile organic compounds. The majority of them have insecticidal, fungicidal, and nematicidal activities. In this review, the classifications, biosynthetic pathways, and ecological functions of primary and secondary metabolites produced by microorganisms are discussed, including their mechanisms of action, ranging from competition to systemic acquired resistance in host plants. The article highlights the importance of microbial genera (viz., Bacillus sp., Pseudomonas sp., Trichoderma sp., Streptomyces sp., etc.) in making chemicals and biopesticides for crop defense. We present the possible applications of microbial biosynthesis strategies and synthetic biology tools in bioprocess development, covering recent innovations in formulation, delivery, and pathway engineering to enhance metabolite production. This review emphasizes the significance of microbial metabolites in improving the plant immunity, yield performance, reduction in pesticide application, and the sustainability of an ecological, sustainable, and resilient agricultural system. Full article

Methylamines are present in numerous organisms and microorganisms capable of de novo trimethylamine (TMA) production are widely distributed, including microalgae. However, such compounds may hamper the application of microalgae biomass in commercially interesting products, such as food and feed products, due to the strong fishy smell. In the present study, several bacteria able to degrade TMA were isolated. Among them, a Staphylococcus saprophyticus strain was found particularly suitable to degrade TMA. After finding the best culture conditions, a bioprocess system was developed allowing the degradation of TMA from microalgae in a reactor by S. saprophyticus cells present in a second reactor without direct contact with media from both reactors. The system was found to be limited by TMA transfer through the gas phase, with the cells being able to degrade all available TMA. Full article

Tomatoes (Solanum lycopersicum) and potatoes (Solanum tuberosum) are vital staple crops. They are prone to diseases from pathogens like Ralstonia and Fusarium, which cause significant agricultural losses. Detecting volatile organic compounds (VOCs) emitted by plants under stress offers a promising approach for advanced monitoring of crop health. This study examines sensing materials for wearable plant sensors targeting VOCs as biomarkers under abiotic and biotic stress. Key questions addressed include the specific VOC emission profiles of potato and tomato cultivars, how materials and sensing mechanisms influence sensor performance, and material considerations for agricultural use. The analysis reveals cultivar-specific VOC profiles under stress, challenging the identification of universal biomarkers for specific diseases. Through a literature review, this study reviews VOC responses to fungi, bacteria, and viruses, and compares non-composite and hybrid chemiresistive and electrochemical sensors based on sensitivity, selectivity, detection limits, response time, robustness, cost-effectiveness, and biocompatibility. A superstructure bridging materials science, plant pathology, AI, data science, and manufacturing is proposed, emphasizing three strategies: sensitivity, flexibility, and sustainability. This study identifies recent research trends that involve developing biodegradable wearable sensors for precision agriculture, leveraging flexible biocompatible materials, multi-parameter monitoring, self-healing properties, 3D-printed designs, advanced nanomaterials, and energy-harvesting technologies. Full article

The insect olfactory system is vital for survival, enabling the recognition and discrimination of a wide range of odorants present in the environment. This process is mediated by odorant receptors (Ors) and the highly conserved co-receptor Orco. Insect Ors are structurally distinct from mammalian olfactory receptors, a divergence that presents unique advantages for developing insect-specific pest control strategies. In this study, we explored the molecular-level interactions between insect Ors and volatile organic compounds. Specifically, we investigated the response of Ors/Orco to phenethyl acetate (PA), a volatile compound found in the culture media of acetic acid bacteria. PA elicited activation in a concentration-dependent, reversible, and voltage-independent manner in Or1a, Or24a, and Or35a when combined with Orco, as well as in Orco homomers. Through molecular docking studies, we determined that the PA-binding site is localized to the Orco subunit, a highly conserved protein across diverse insect taxa. To further elucidate the role of key residues in the Orco homotetramer receptor, we performed site-directed mutagenesis. A mutational analysis identified W146 and E153 as critical residues for PA binding and activation. A double-mutant Orco receptor (W146A + E153A) exhibited a significant reduction in PA-induced activation compared to the wild-type receptor. These findings indicate that PA functions as an agonist for the Drosophila melanogaster Orco receptor and highlight its potential applications in chemosensory research and insect pest management strategies. Full article

The variation in organic acids during malolactic fermentation (MLF) affects the wine’s quality, presenting a challenge for the wine industry. This study aimed to investigate the kinetics of organic acids during MLF using two Oenococcus oeni strains under different barrel conditions. The study examined the variation in pH, total and volatile acidity, and concentration of tartaric, malic, lactic, and citric acid during MLF in the identical initial wine. In addition, the aromatic profile of the final wines was evaluated. The fermentation occurred in new and used French oak barrels. Two strains of O. oeni were used: (a) citrate-negative O. oeni (CINE) and (b) O. oeni, commonly used in the wine industry. The experimental data obtained were fitted to the logistic model for each monitored parameter. The degree of fitting R2 was higher than 92.79%, indicating good predictive accuracy for substrate consumption (malic and citric acid), as well as product formation (lactic and acetic acid). The mean values of O. oeni and O. oeni CINE differ in acetic (0.29 and 0.15 g/L) and citric acid (0.13 and 0.18 g/L), respectively. The logistic model effectively predicted the change in acid content during fermentation, describing the changes in organic acid levels during the MLF conducted in barrels. Modeling can be useful in forecasting industrial-scale production. Full article

Roasted carob flour is a sustainable ingredient rich in dietary fiber, polyphenols, and pinitol, offering potential for both food and pharmaceutical applications. However, its high sugar content and the presence of undesirable compounds such as furans present challenges for its use in bread making. This study evaluated the effects of prolonged sourdough fermentation on roasted carob flour, with a focus on microbial dynamics and its functional and technological properties. Carob and carob–wheat sourdoughs were prepared using a mixed starter culture comprising three lactic acid bacteria (Lactiplantibacillus plantarum, Fructilactobacillus sanfranciscensis, and Lactobacillus helveticus) and three yeast species (Saccharomyces cerevisiae, Kazachstania humilis, and Torulaspora delbrueckii). The sourdoughs underwent six consecutive refreshment cycles and were analyzed to determine their pH, microbial and biochemical composition, gassing power, and volatile organic compounds (VOCs). The carob–wheat sourdough exhibited faster acidification and higher lactic acid bacteria (LAB) activity, resulting in a 90–98% reduction in the sugar content, compared to 60% in the carob sourdough. Microbial sequencing revealed that L. plantarum was the dominant species in all samples, while K. humilis and S. cerevisiae were enriched in carob and carob–wheat sourdough, respectively. Both types of sourdough demonstrated effective leavening in bread dough without the addition of commercial yeast. Fermentation also modified the VOC profiles, increasing esters and alcohols while reducing acids, aldehydes, ketones, and furans. While the antioxidant activity showed a slight decline, the pinitol content remained unchanged. These findings suggest that extended sourdough fermentation, supported by multiple refreshments, enhances the baking suitability of roasted carob flour and supports its application as a functional, sustainable ingredient. Full article

Indoor air pollution is a serious public health issue caused by the accumulation of numerous toxic contaminants within enclosed spaces. Particulate matter (PM_2.5 and PM₁₀), biological contaminants (mould, bacteria, and allergies), inorganic gases (carbon monoxide, carbon dioxide, ozone, and nitrogen dioxide), and a variety of volatile organic compounds (VOCs) are examples of common indoor air pollutants. VOCs are one of the chief indoor contaminants, and their effects on human health have made indoor air quality a serious concern. Indoor VOC concentrations are frequently higher than outdoor levels, according to studies, which raises the danger of exposure, particularly for young people and those with respiratory disorders. VOCs originate from both biogenic and anthropogenic sources, and they can create secondary pollutants like ozone and aerosols, which can lead to cardiovascular and pulmonary problems. Prolonged exposure to VOCs has been associated with respiratory irritation, neurological effects, and an increased risk of chronic diseases. This review examines the primary sources, sampling and analysis approach, and health impact of VOCs in indoor air. Additionally, we compared worldwide regulatory guidelines for VOC exposure limits, emphasizing the need for strict exposure limits to protect human health. Full article

Bioaerosols have risen as pivotal constituents of airborne particles. Closely intertwined with the agricultural domain, these particles exert a significant influence on crops through the dissemination of various microorganisms that modulate crop growth dynamics, adaptive responses to environmental stimuli, and the nutritional profile of agricultural products. As the main vector, airborne particles are at the forefront in the transmission of plant pathogens. Therefore, this review explains the main factors influencing their composition in agricultural settings and their spreading. Furthermore, it elucidates the complex bioaerosol-based communication networks, including bacteria–bacteria, bacteria–plant, and plant–plant interactions, mediated by specialized volatile organic compounds (VOCs) released by plants and bacterial volatile compounds (BVCs) produced by bacteria. These compounds play a crucial role in synchronizing stress responses and facilitating adaptive processes. They serve as a pathway for influencing and regulating the behavior of both plants and microorganisms. Delving into their origin and dispersion, we assess the key methods for their collection and analysis while also comparing the strengths and weaknesses of various sampling techniques. The discussion also extends to delineating the roles of such particles in the formation of biodiversity. Central to this discourse is an in-depth exploration of their role in the agricultural context, particularly focusing on their potential utility in forecasting pathogen transmission and subsequent plant diseases. This review also highlights the importance of applying bioaerosol-based strategies in the promotion of sustainable agricultural practices, thus contributing to the advancement of ecological balance and food security, which remains a neglected area in scientific research. Full article