In viticulture, temporary cover crops and organic mulching are sustainable practices that enhance biodiversity, improve soil fertility, and strengthen grapevine health/resilience, particularly in Mediterranean regions. However, their impact on microbial communities associated with grapevines in non-irrigated vineyards remains largely unexplored. Inter-row soil management included a cereal-based cover crop (CC), a mixed cereals, legumes and brassicas cover crop (MC), and a control with alternating soil tillage and spontaneous grass (GT). In spring, cover crops were terminated to form a dry mulch under the vine rows. At veraison, under-row dry mulching significantly maintained higher soil water availability and reduced soil temperature by approximately 2.5°C compared to the GT treatment. CC, in particular, enhanced grapevine physiological performances. These different soil conditions positively shaped the rhizosphere microbiome by maintaining higher microbial richness and promoting nutrient-cycling microorganisms (e.g., Bradyrhizobium sp., Nitrospira japonica) in both CC and MC. In contrast, the GT treatment selectively favored drought-tolerant plant growth-promoting rhizobacteria (PGPR) taxa such as Bacillus zanthoxyli, Gaiella occulta, Roseiflexus sp., Pseudarthrobacter sp., and Paenibacillus sp. In the phyllosphere, the abundance of Erysiphe necator, the powdery mildew agent, was lower in CC and MC, which also showed a higher presence of Aureobasidium pullulans, a species reported in the literature as a potential biocontrol agent. Our results suggest that under-row dry mulching, by modifying soil conditions, can have a positive effect on grapevine microbial richness and biodiversity during the dry summer period, serving as an indicator of improved vineyard agroecosystem health and sustainability.

ABSTRACT Pullulan, a microbial exopolysaccharide primarily produced by Aureobasidium pullulans , has drawn a lot of interest as a sustainable biopolymer for food packaging due to its biodegradability, nontoxicity and superior film‐forming qualities. This review thoroughly discusses the sources, production methods using agro‐industrial wastes, the chemical structure and physicochemical properties of pullulan, which makes it ideal for food packaging applications. Several kinds of fabrication techniques, such as solvent casting, electrospinning, dipping and layer‐by‐layer assembly, have been examined, with a focus on composite formulations that combine pullulan with other biopolymers and bioactive compounds to improve mechanical strength, water vapour resistance, oxygen barrier and antimicrobial properties. Natural extracts, essential oils and nanoparticles have been shown to provide active packaging properties to pullulan‐based packaging that prolong shelf life and maintain quality in a variety of food such as fruits, vegetables, meats and seafood. Through chemical changes and multilayer structures, pullulan‐based films exhibit flexibility despite issues with mechanical limits and moisture sensitivity. In order to address environmental issues associated with synthetic plastics, this review focuses on recent developments in functional pullulan packaging, establishing pullulan as a crucial component of environmentally friendly, biodegradable food packaging.

Enhanced β-glucan production in Aureobasidium pullulans via combinatorial ARTP mutagenesis, dual-dye screening, and medium optimization.

Rhizospheric microorganisms play a crucial role in plant vitality by contributing to nutrient supply and overall plant health. This research focused on a specific yeast isolated from the rhizosphere of Rosa hybrid delflobla and aimed to investigate if a resulting natural active ingredient can have cosmetic benefits, particularly concerning NAD+, a cofactor known to play a vital role in skin longevity. The yeast Aureobasidium pullulans, sampled in the rhizosphere of Rosa hybrid delflobla, was processed to generate a natural active ingredient (INCI: Aureobasidium pullulans ferment). The efficacy of this active ingredient was investigated on NAD+ (nicotinamide adenine dinucleotide) synthesis, a crucial molecule playing a fundamental role in energy metabolism and a multitude of key cellular processes, as well as on cutaneous barrier function and related skin benefits. The results of this study demonstrate that the Aureobasidium pullulans ferment increases the NAD+/NADH ratio. Moreover, the expression and synthesis of epidermal differentiation and cohesion markers are stimulated with this natural active ingredient, resulting in an improved barrier function. Clinical results demonstrate that the Aureobasidium pullulans ferment smooths skin microrelief and enhances complexion radiance. Altogether, these results reveal that the active ingredient obtained from the Rosa hybrid delflobla rhizosphere (INCI: Aureobasidium pullulans ferment) has highly interesting potential to improve skin resilience and longevity.

Diverse fungi have been historically vital reservoirs of drug discovery, providing life-saving pharmaceuticals. Many species of fungi, yeasts in particular, are highly resistant to radiation, with their cellular contents potentially conferring dietary radioresistance. We developed a Drosophila model to test whether feeding two highly radioresistant fungi, Aureobasidium pullulans and Rhodotorula taiwanensis, could improve fly lifespan and gut morphology after acute irradiation. We constructed a dosimetry curve for the lifespan response of males and females to irradiation and found dose-dependent and sex-specific effects on lifespan. We also determined that the sex-specific response to irradiation correlated with nuclear morphology defects in the gut, with the more radiosensitive males displaying increased midgut cellular holes and aberrant nuclear morphology. To determine if feeding Aureobasidium pullulans and Rhodotorula taiwanensis before irradiation could improve survival and gut morphology, we first exclusively fed males and females each fungus and observed that they tolerated the diet well. Using these methods, we found that only two days of pre-feeding Aureobasidium pullulans increased male lifespan, but not female, after irradiation, and improved nuclear morphology in the gut. However, dietary Rhodotorula taiwanensis was not protective. Overall, this study identified a highly radioresistant dietary fungus, Aureobasidium pullulans, as effective for extending male Drosophila lifespan and improving gut morphology following irradiation. Since the gut is particularly sensitive to the effects of irradiation, this fungus indicates a potential therapeutic for patients undergoing radiotherapy. Furthermore, this method could identify additional radioresistant fungi that protect the gut from radiation injury.

Exploring the biochemical, technical and applicative characteristics of pullulan produced by different strains of Aureobasidium pullulans

Eleven compounds were isolated from the secondary metabolites of the marine fungus Aureobasidium pullulans 8438, including three novel compounds, 9-hydroxy-massoia lactone (1), Ethyl p-hydroxybenzoate (3 R,5R)-3,5-dihydroxydecanoate (2), and (R)-9,10-dihydroxypropyl 4-hydroxy-5-((2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien −1-yl) benzoate (3), along with 8 known compounds (4–11). Compounds 1, 2 and 4–9 are decanoic acid derivatives, while both compounds 3 and 11 are 3-farnesyl-p-hydroxybenzoic acid derivatives. The planar structures of the new compounds were determined using high-resolution mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR) data. Their absolute configurations were established through the Snatzke method, quantum chemical calculations (including computational NMR and ECD), and DP4+ analysis. All isolated compounds were evaluated for their cytotoxic effects against human non-small cell lung cancer cells A549 and human cervical cancer cells HeLa.

Extreme environments are a largely unexplored reservoir of microbial diversity, with a remarkable potential to be exploited in agriculture. One hundred and seventeen yeast isolates, derived from different ecosystems in Italy, Sweden, Algeria, and France, were molecularly identified, and the most represented genus was Aureobasidium (57%). A phylogenetic analysis based on a multi-locus sequence typing (ITS, ELO, EF-1alpha) was conducted to characterize the black yeasts’ population. To investigate A. pullulans extremophilic and extremotolerant behaviour, different temperatures and pH, together with the enzymatic production, were evaluated. The strains were tested by in vitro and in vivo assays against the postharvest fungal pathogen Monilinia fructicola as potential biocontrol agents (BCAs). Results displayed a great ecological variability concerning strains’ growth and cell production depending on different culture conditions. However, a remarkable thermotolerance aptitude was detected in almost all the strains. In particular, the strains belonging to Group 2 (Algerian Desert) and 3 (Alto Adige Region) showed, respectively, higher thermotolerance and biocontrol ability. These findings showed how some extreme environments could represent a promising source for new potential BCAs. However, further studies are needed to investigate the mechanisms of action of these putative BCAs for application during the postharvest phase.

Budding yeasts present an especially challenging geometry for segregation of chromosomes, which must be delivered across the narrow mother-bud neck into the bud. Studies in the model yeast Saccharomyces cerevisiae have revealed an elaborate set of mechanisms that selectively orient one mitotic spindle pole toward the bud and then drive spindle elongation along the mother-bud axis, ensuring nuclear segregation between mother and bud. It is unclear how these pathways might be adapted to yield similar precision in more complex cell geometries. Here, we provide the first description of the dynamics of mitosis in a multinucleate, multibudding yeast, Aureobasidium pullulans, and identify many unexpected differences from uninucleate yeasts. Mitotic spindles do not orient along the mother-bud axis prior to anaphase, and accurate nuclear segregation often occurs after spindle disassembly. Cortical Num1-dynein forces pull highly mobile nuclei into buds, and once a nucleus enters a bud, it discourages others from entering, ensuring that most daughters inherit only one nucleus.

Changes in microbial assembly and ecological processes following application of Aureobasidium pullulans on apple fruit surface.

Simultaneous production and sequential recovery of xylanase and bioactive phenolic compounds via solid-state fermentation of wheat bran by Aureobasidium pullulans NRRL Y-2311-1.

Grape berries provide a natural habitat for diverse microorganisms, including potentially toxinogenic species. This study investigated the exogenous and endogenous mycocenosis of grapes, focusing on Aspergillus and Penicillium species and their toxinogenic potential, alongside the antioxidant profile (antioxidant activity and total polyphenol content) of four grape samples from the Tokaj wine-growing region in 2023. Exogenous and endogenous fungal communities were analyzed using plating methods, with surface disinfection for endogenous mycobiota. Micromycetes were identified morphologically, and yeasts were characterized using MALDI-TOF MS Biotyper. We isolated 458 fungal colonies across four genera (Aspergillus, Penicillium, Rhizopus, and Trichoderma) from exogenous mycocenosis, with Penicillium being the most frequent and abundant. From endogenous mycocenosis, 202 isolates across six genera (Alternaria, Aspergillus, Cladosporium, Penicillium, Rhizopus, and Trichoderma) were identified, with Penicillium dominating. Yeasts detected included Pichia terricola, Aureobasidium pullulans, Hanseniaspora uvarum, and Pichia fermentans. Toxinogenicity testing revealed that Penicillium expansum produced citrinin, while Aspergillus clavatus did not produce patulin under in vitro conditions. The Zéta grape variety showed the highest antioxidant activity (1.49 mg TEAC/g FM) and polyphenol content (3.15 mg GAE/g FM). These findings underscore the dual role of grapes as a source of valuable phytochemicals and a potential habitat for toxin-producing fungi, which could impact grape safety and quality. Future research should explore the relationship between grape microbiome composition and phytochemical profiles, as well as expand the study to other wine-growing regions to support sustainable grape production and food safety.

Actin is highly conserved across eukaryotes. This versatile protein builds cytoskeletal networks central to diverse cellular processes, including cell division and cell motility. The most potent and broadly used reagents to detect polymerized actin distribution in fixed cells are fluorescently conjugated derivatives of the basidiomycete-derived toxin, phalloidin. However, despite its conservation, actin in many ascomycete fungi fails to bind phalloidin. Here, we trace the failure to bind phalloidin to a single amino acid change in a phalloidin-binding residue in actin. Reverting this change in the fungi Aureobasidium pullulans and Aspergillus nidulans by introducing the point mutation act1V75I at the native ACT1 locus confers phalloidin binding while retaining actin function. This strategy should enable characterization of F-actin in a wider range of fungi.IMPORTANCEHigh-resolution tools to visualize filamentous actin networks are critical to the investigation of organisms' cell biology. The gold standard tool is fluorescent phalloidin, a mushroom toxin. However, several fungi have actin that fails to stain with phalloidin. Here, we describe a way to reverse that failure, rendering the invisible actin visible.

Microbial enzymes, due to their efficiency, specificity, and sustainability, are central to innovative biotechnological strategies aimed at optimizing industrial processes such as winemaking. In this study, the potential of Aureobasidium pullulans m11-2, a native dimorphic fungus from the wine ecosystem, was evaluated as a source of hydrolytic enzymes capable of degrading grape cell wall polysaccharides. The strain was identified at the molecular level and characterised in terms of its morphology. To maximise enzyme production, various culture media were tested. Among the concentrations tested, the optimal levels of glucose and pectin were 1 g L−1 and 10 g L−1, respectively. The partially constitutive and inducible nature of the various polysaccharidase activities (pectinases, cellulases, and xylanases) was confirmed. The effect of grape skins (a winemaking by-product) on microbial growth and enzyme synthesis was evaluated, achieving a pectinase activity of 0.622 U mL−1 when combined with 1 g L−1 of glucose. Maximum enzyme yields were detected during the exponential growth phase in both citrus pectin and grape skin media, suggesting favorable conditions for continuous bioprocessing. These results confirm that A. pullulans m11-2 is an interesting microbial option for producing polysaccharidases that can be adapted to sustainable production systems.

Increasing Aureobasidium pullulans β-Glucan water solubility by carboxymethylation modification and its characterization study

Cell division commonly produces two daughter cells, but there are many exceptions where large cells produce multiple daughters. Multiple fission of some green algae and bacteria; cellularization during embryogenesis of plants and insects; and growth of Ichthyosporeans, Chytrids, and Apicomplexans all provide variations on this theme. In some yeast species, a large multinucleate mother cell grows multiple buds (daughters) simultaneously. Here, we address how mothers partition growth equally among their buds in the multi-budding yeast Aureobasidium pullulans. Bud growth is directed by actin cable networks that appear to be optimized for even partitioning despite complex cell geometries. Even partitioning does not rely on compensatory mechanisms to adjust bud volumes but rather stems directly from effective equalization of polarity sites. These results reveal how conserved cell polarity and cytoskeletal networks are adapted to build complex morphologies in fungi.

BackgroundPreventing oral infections, such as oral caries and periodontal disease, helps reduce the risks of various systemic diseases. In this study, the polysaccharide pullulan produced by the black yeast Aureobasidium pullulans was modified in combination with the cationic surfactant cetylpyridinium chloride (CPC) to create a local drug delivery system, and its antibacterial potential on oral bacteria was examined in vitro.MethodsPullulan was phosphorylated at the CH2OH residue of α6 in the maltotriose structure and mixed with CPC. Bacterial attachment of cariogenic Streptococcus mutans on hydroxyapatite plates (HAPs) treated with the phosphorylated pullulan (PP) and CPC compound (0.01% PP and 0.001– 0.03% CPC, and vice versa) was assessed by observing bacteria using a field emission scanning electron microscope (FE-SEM) and quantified through 16 S rRNA amplification via real-time polymerase chain reaction (PCR). Additionally, the quartz crystal microbalance (QCM) method was employed to evaluate the sustained release of CPC.ResultsPP-CPC compound maintained significant bactericidal activity even at 0.01%, which is one-fifth of the conventional applicable concentration of CPC. Additionally, a residual mixture was detected by the hydroxyapatite sensor of the crystal oscillator microbalance detector, suggesting an unknown molecular interaction that enables the sustained release of CPC after attachment to hydroxyapatite.ConclusionsThe combination of PP and CPC may contribute to the low concentration and effective prevention of oral infections, such as dental caries.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12903-025-06666-z.

An iterative approach to statistical optimization of exopolysaccharide produced by fermentation of Aureobasidium pullulans

Liamocins are unique extracellular glycolipid biosurfactantsproducedby certain species of Aureobasidium pullulans with potential applications in agriculture, food, medicine, andpharmaceutical industries due to their surface-active properties andantimicrobial activity. In this study, for the first time, optimizationof various fermentation parameters for liamocin production by A. pullulans NBRC 100716 strain was carried out usingthe response surface methodology (RSM). By conducting numeric optimization,the optimum conditions were determined as follows: initial substrate(fructose) concentration (X1) of 93.47 g/L, initialpH (X2) of 4.92, and temperature (X3) of 27.2 °C. Under optimum conditions, the maximum liamocinconcentration (Y1), microorganism-specific growthrate (Y2), and maximum specific liamocin productionrate (Y3) were found to be 3.56 g/L, 0.0670 h–1, and 0.00450 [g liamocin/(g mo·h)], respectively.Variations of the responses with the independent variables were definedby a quadratic model. According to the analysis of variance (ANOVA)results, the model terms in the study showed high significance (p < 0.05) for all response variables, while the lackof fit was not significant for any of the responses. The coefficientof determination for liamocin production (0.829) was close to 1.0,confirming the significance of the model. Matrix-assisted laser desorptionionization time-of-flight mass spectrometry (MALDI-TOF-MS) determinedthat the liamocin structure contained all liamocin types referredto as A1, B1, A2, and B2. By the gas chromatography-flame ionizationdetection (GC-FID) method, it was determined that 61.12% of the fattyacid composition consisted of saturated and 38.87% consisted of unsaturatedfatty acids (UFA). Furthermore, Fourier transform infrared spectrometry(FT-IR) spectral attributes were used for the first time to confirmthe structure of liamocin, providing valuable insights. This study,in which some fermentation parameters were optimized, showed thatthe A. pullulans NBRC 100716 strainis promising for industrial-scale liamocin production in the future.

High-throughput screening of Aureobasidium pullulans for high β-glucan production using UV mutagenesis combined with artificial fluorescent labeling.