Clinicopathological study of otomycosis in a tertiary hospital in South-west Nigeria.

Background: Otomycosis is common in environments with hot, humid weather, and it may be challenging to manage. Objectives: To profile common clinical presentations, the pathogenic fungi, the treatment modalities with responses, and explore clinical factors associated with having positive fungal culture in Otomycosis. Methods: Retrospective review of patients with Otomycosis. Demographic and clinical parameters, otoscopic findings and mycological study results were recorded. The treatment modalities used and treatment response were summarized. Comparative statistical analyses of associated factors to positive fungal culture were performed with Chi square test, and Student's t-test, using SPSS version 22.0. Results: Total of 71 patients with M: F=1:1.8, mean age 38.5±19.8 years. Average duration of symptoms was 5.4 ±4.6 weeks; common presenting complaint was itchy ear (33.8%). Majority of patients (85.9%) had unilateral ear involvement, 50.0% applied ototopic medications before presentation, 8.5% had multiple co-morbidities. 20 patients had positive fungal culture results; common fungal isolate was Aspergillus niger 9 (45.0%).Clinical factors associated with positive culture of fungus were age, non-previous use of ototopic drugs, and presence of co-morbidity. The most common treatment was local ear debridement and use of topical antifungal creams. Majority (91.5%) of the patients responded with resolution of fungal infection. Complications rate was 8.4%. Conclusions: Otomycosis commonly present with itchy ears, the pathogenic fungi commonly being Aspergillus species. The factors associated with positive fungal culture were age, non-usage of ototopic agents and presence of co-morbidity. Treatment modality used was local debridement and topical antifungal agents, which produced favourable response in most patients.

Phosphate solubilizing Aspergillus Niger PH1 ameliorates growth and alleviates lead stress in maize through improved photosynthetic and antioxidant response.

Among the several threats to humanity by anthropogenic activities, contamination of the environment by heavy metals is of great concern. Upon entry into the food chain, these metals cause serious hazards to plants and other organisms including humans. Use of microbes for bioremediation of the soil and stress mitigation in plants are among the preferred strategies to provide an efficient, cost-effective, eco-friendly solution of the problem. The current investigation is an attempt in this direction where fungal strain PH1 was isolated from the rhizosphere of Parthenium hysterophorus which was identified as Aspergillus niger by sequence homology of the ITS 1 and ITS 4 regions of the rRNA. The strain was tested for its effect on growth and biochemical parameters as reflection of its potential to mitigate Pb stress in Zea mays exposed to 100, 200 and 500 µg of Pb/g of soil. In the initial screening, it was revealed that the strain has the ability to tolerate lead stress, solubilize insoluble phosphate and produce plant growth promoting hormones (IAA and SA) and other metabolites like phenolics, flavonoids, sugar, protein and lipids. Under 500 µg of Pb/g of soil, Z. mays exhibited significant growth retardation with a reduction of 31% in root length, 30.5% in shoot length, 57.5% in fresh weight and 45.2% in dry weight as compared to control plants. Inoculation of A. niger to Pb treated plants not only restored root and shoot length, rather promoted it to a level significantly higher than the control plants. Association of the strain modulated the physio-hormonal attributes of maize plants that resulted in their better growth which indicated a state of low stress. Additionally, the strain boosted the antioxidant defence system of the maize there by causing a significant reduction in the ascorbic acid peroxidase (1.5%), catalase (19%) and 1,1-diphenyl-2 picrylhydrazyl (DPPH) radical scavenging activity (33.3%), indicating a lower stress condition as compared to their non-inoculated stressed plants. Based on current evidence, this strain can potentially be used as a biofertilizer for Pb-contaminated sites where it will improve overall plant health with the hope of achieving better biological and agricultural yields.

Preparation of Pinoresinol and Dehydrodiconiferyl Alcohol from Eucommiae Cortex Extract by Fermentation with Traditional Mucor.

Eucommiae Cortex (EC) is frequently used alone or in combination with other active ingredients to treat a range of illnesses. An efficient technical instrument for changing cheap or plentiful organic chemicals into rare or costly counterparts is biotransformation. It combines EC with biotransformation techniques with the aim of producing some novel active ingredients, using different strains of bacteria that were introduced to biotransform EC in an aseptic environment. The high-quality strains were screened for identification after the fermentation broth was found using HPLC, and the primary unidentified chemicals were separated and purified in order to be structurally identified. Strain 1 was identified as Aspergillus niger and strain 2 as Actinomucor elegans; the main transformation product A was identified as pinoresinol (Pin) and B as dehydrodiconiferyl alcohol (DA). The biotransformation of EC utilizing Aspergillus niger and Actinomucor elegans is reported for the first time in this study's conclusion, resulting in the production of Pin and DA.

Aspergillus niger as an efficient biological agent for separator sludge remediation: two-level factorial design for optimal fermentation.

Background: The booming palm oil industry is in line with the growing population worldwide and surge in demand. This leads to a massive generation of palm oil mill effluent (POME). POME is composed of sterilizer condensate (SC), separator sludge (SS), and hydro-cyclone wastewater (HCW). Comparatively, SS exhibits the highest organic content, resulting in various environmental impacts. However, past studies mainly focused on treating the final effluent. Therefore, this pioneering research investigated the optimization of pollutant removal in SS via different aspects of bioremediation, including experimental conditions, treatment efficiencies, mechanisms, and degradation pathways. Methods: A two-level factorial design was employed to optimize the removal of chemical oxygen demand (COD) and turbidity using Aspergillus niger. Bioremediation of SS was performed through submerged fermentation (SmF) under several independent variables, including temperature (20-40 °C), agitation speed (100-200 RPM), fermentation duration (72-240 h), and initial sample concentration (20-100%). The characteristics of the treated SS were then compared to that of raw sludge. Results: Optimal COD and turbidity removal were achieved at 37 °C 100 RPM, 156 h, and 100% sludge. The analysis of variance (ANOVA) revealed a significant effect of selective individual and interacting variables (p < 0.05). The highest COD and turbidity removal were 97.43% and 95.11%, respectively, with less than 5% error from the predicted values. Remarkably, the selected optimized conditions also reduced other polluting attributes, namely, biological oxygen demand (BOD), oil and grease (OG), color, and carbon content. In short, this study demonstrated the effectiveness of A. niger in treating SS through the application of a two-level factorial design.

Posaconazole-hemp seed oil loaded nanomicelles for invasive fungal disease.

Invasive fungal infections (IFI) pose a significant health burden, leading to high morbidity, mortality, and treatment costs. This study aims to develop and characterize nanomicelles for the codelivery of posaconazole and hemp seed oil for IFI via the oral route. The nanomicelles were prepared using a nanoprecipitation method and optimized through the Box Behnken design. The optimized nanomicelles resulted in satisfactory results for zeta potential, size, PDI, entrapment efficiency, TEM, and stability studies. FTIR and DSC results confirm the compatibility and amorphous state of the prepared nanomicelles. Confocal laser scanning microscopy showed that the optimized nanomicelles penetrated the tissue more deeply (44.9µm) than the suspension (25µm). The drug-loaded nanomicelles exhibited sustained cumulative drug release of 95.48 ± 3.27% for 24 h. The nanomicelles showed significant inhibition against Aspergillus niger and Candida albicans (22.4 ± 0.21 and 32.2 ± 0.46 mm, respectively). The pharmacokinetic study on Wistar rats exhibited a 1.8-fold increase in relative bioavailability for the nanomicelles compared to the suspension. These results confirm their therapeutic efficacy and lay the groundwork for future research and clinical applications, providing a promising synergistic antifungal nanomicelles approach for treating IFIs.

Aspergillus niger prolyl endopeptidase in celiac disease.

We comment here on the article by Stefanolo et al entitled "Effect of Aspergillus niger prolyl endopeptidase in patients with celiac disease on a long-term gluten-free diet", published in the World Journal of Gastroenterology. Celiac disease is a well-recognized systemic autoimmune disorder. In genetically susceptible people, the most evident damage is located in the small intestine, and is caused and worsened by the ingestion of gluten. For that reason, celiac patients adopt a gluten-free diet (GFD), but it has some limitations, and it does not prevent re-exposure to gluten. Research aims to develop adjuvant therapies, and one of the most studied alternatives is supplementation with Aspergillus niger prolyl endopeptidase protease (AN-PEP), which is able to degrade gluten in the stomach, reducing its concentration in the small intestine. The study found a high adherence to the GFD, but did not address AN-PEP as a gluten immunogenic peptide reducer, as it was only tested in patients following a GFD and not in gluten-exposing conditions. This study opens up new research perspectives in this area and shows that further study is needed to clarify the points that are still in doubt.

The chemotrophic behaviour of Aspergillus niger: Mapping hyphal filaments during chemo-sensing; the first step towards directed materials formation.

In the development of fungal based materials for applications in construction through to biomedical materials and fashion, understanding how to regulate and direct growth is key for gaining control over the form of material generated. Here, we show how simple 'chemical food' cues can be used to manipulate the growth of fungal networks by taking Aspergillus niger as an exemplar species. Chemotrophic responses towards a range of nitrogen and carbon containing biomolecules including amino acids, sugars and sugar alcohols were quantified in terms of chemotrophic index (CI) under a range of basal media compositions (low and high concentrations of N and C sources). Growth of filamentous networks was followed using fluorescence microscopy at single time points and during growth by an AI analytical approach to explore chemo sensing behaviour of the fungus when exposed to pairs (C-C, C-N, N-N) of biomolecules simultaneously. Data suggests that the directive growth of A. niger can be controlled towards simple biomolecules with CI values giving a good approximation for expected growth under a range of growth conditions. This is a first step towards identifying conditions for researcher-led directed growth of hyphae to make mycelial mats with tuneable morphological, physicochemical, and mechanical characteristics.

Type III sourdough: Evaluation of biopreservative potential in bakery products with enhanced antifungal activity.

The potential biopreservative role of a Type III sourdough (tIII-SD), produced by starter cultures of Fructilactobacillus sanfranciscensis and Lactiplantibacillus plantarum ATCC 8014, was assessed for its antifungal activity in baking applications. Fermentation was carried out using different substrates to enhance the production of antifungal metabolites for 24 and 48 h. The tIII-SD samples were analyzed in relation to pH, total titratable acidity (TTA) and the production of organic acids. The water/salt-soluble extract of the tIII-SD was evaluated in relation to the inhibition potential against key fungi that contaminate bakery products including Penicillium roqueforti, Penicillium chrysogenum and Aspergillus niger. Finally, breads with 10 % of the tIII-SD were prepared and the fungi contamination was evaluated throughout the shelf life period. The lowest pH value in sourdough was obtained from 48-hour fermentation by L. plantarum. The saline extracts exhibited varying degrees of inhibition in the in vitro test; however, the greatest enhancement of this effect was obtained when whole wheat grain flour was used. The tIII-SD crafted from a blend of wheat and flaxseed flours and fermented with F. sanfranciscensis for 48 h (BSWF48h-FS), demonstrated superior performance compared to other formulations. This variant exhibited a total shelf life of 10 days, suggesting that the utilization of tIII-SD could serve as a viable alternative for natural antifungal agents, proving beneficial for the bakery industry.

Optimization of Antifungal Properties of Hop Cone Carbon Dioxide Extracts Based on Response Surface Methodology.

Response surface methodology (RSM) was employed to optimize the process parameters of the supercritical carbon dioxide extraction of hop cones in terms of their antifungal properties against Fusarium culmorum and Aspergillus niger. The effects of temperature (40-50 °C), pressure (200-300 bar), and CO2 consumption (25-75 kgCO2/kg) on the extraction yield, content of α- and ß-acids, as well as pathogens' growth inhibition were investigated. Both pressure and CO2 consumption had a significant effect on antifungal properties. It was observed that the best results for antifungal properties were obtained when hop cones were extracted with pure carbon dioxide at the temperature of 50 °C, under the pressure of 300 bar with CO2 consumption at the level of 75 kgCO2/kg of feed for extraction. The highest antifungal properties of hop cone supercritical carbon dioxide extracts were analyzed as 100% for Fusarium culmorum and 68% for Aspergillus niger, calculated as the growth inhibition of tested pathogens. The aim of the study was to determine the optimum values of extraction parameters to achieve the maximum response and enable us to investigate the interaction of these parameters on the antifungal properties of hop cone extracts.

Potential antifungal applications of heterometallic silica nanohybrids: A synergistic activity.

An estimated 1.7 million fatalities and 150 million cases worldwide are attributed to fungal infections annually, that are in rise due to immunocompromised patient population. The challenges posed by traditional treatments can be addressed with the help of nanotechnology advancements. In this study, Co, Cu, and Ag-were doped into silica nanoparticles. Then the synthesized monometallic silica nanohybrids were combined to formulate heterometallic silica nanohybrids, characterized structurally and morphologically, compared, and evaluated for antifungal activity based on their individual and synergistic activity. The antifungal assays were conducted by using ATCC cultures of Candida albicans and QC samples of Trichophyton rubrum, Microsporum gypseum, and Aspergillus niger. The MIC (ranging from 49.00 to 1560.00 µg/mL), MFC (ranging from 197.00 to 3125.00 µg/mL), IC50 values (ranging from 31.10 to 400.80 µg/mL), and FICI of nanohybrids were determined and compared. Moreover, well diffusion assay was performed. ABTS assay and DPPH assay were conducted to investigate the radical scavenging activity (RSA) of nanohybrids. SEM analysis clearly evidenced the structural deformations of each fungal cells and spores due to the treatment with trimetallic nanohybrid. According to the results, the trimetallic silica nanohybrids exhibited the most powerful synergistic RSA and the most effective antifungal activity, compared to the bimetallic silica nanohybrids.

Extraction of chitin from flammulina velutipes waste: A low-concentration acid pretreatment and aspergillus Niger fermentation approach.

In recent years, with the booming of the edible mushroom industry, chitin production has become increasingly dependent on fungi and other non-traditional sources. Fungal chitin has advantages including superior performance, simpler separation processes, abundant raw materials, and the absence of shellfish allergens. As a kind of edible mushroom, flammulina velutipes (F. velutipes) also has the advantages of wide source and large annual yield. This provided the possibility for the extraction of chitin. Here, a procedure to extract chitin from F. velutipes waste be presented. This method comprises low-concentration acid pretreatment coupled with consolidated bioprocessing with Aspergillus niger. Characterization by SEM, FTIR, XRD, NMR, and TGA confirmed that the extracted chitin was ß-chitin. To achieve optimal fermentation of F. velutipes waste (80 g/L), ammonium sulfate and glucose were selected as nitrogen and carbon sources (5 g/L), with a fermentation time of 5 days. The extracted chitin could be further deacetylated and purified to obtain high-purity chitosan (99.2 % ± 1.07 %). This chitosan exhibited a wide degree of deacetylation (50.0 % ± 1.33 % - 92.1 % ± 0.97 %) and a molecular weight distribution of 92-192 kDa. Notably, the yield of chitosan extracted in this study was increased by 56.3 % ± 0.47 % compared to the traditional chemical extraction method.

Unveiling the synthesis of aromatic compounds in sauce-flavor Daqu from the functional microorganisms to enzymes.

Aromatic compounds serve as the primary source of floral and fruity aromas in sauce-flavor (Maotai flavor) baijiu, constituting the skeleton components of its flavor profile. Nevertheless, the formation mechanism of these compounds and key aroma-producing enzymes in sauce-flavor Daqu (fermentation agent, SFD) remain elusive. Here, we combined metagenomics, metaproteomics, metabolomics, and key enzyme activity to verify the biosynthesis pathway of aromatic compounds and to identify key enzymes, genes, and characteristic microorganisms in SFD. The results showed that the later period of fermentation was critical for the generation of aromatic compounds in SFD. In-situ verification was conducted on the potential key enzymes and profiles in various metabolites, providing comprehensive evidence for the main synthetic pathways of aromatic compounds in SFD. Notably, our results showed that primary amine oxidase (PrAO) and aldehyde dehydrogenase (ALDH) emerged as two key enzymes promoting aromatic compound synthesis. Additionally, two potential key functional genes regulating aromatics generation were identified during SFD fermentation through correlation analysis between proteins and relevant metabolites, coupled with in vitro amplification test. Furthermore, original functional strains (Aspergillus flavus-C10 and Aspergillus niger-IN2) exhibiting high PrAO and ALDH production were successfully isolated from SFD, thus validating the results of metagenomics and metaproteomics analyses. This study comprehensively elucidates the pathway of aromatic compound formation in SFD at the genetic, proteomic, enzymatic, and metabolomic levels, providing new ideas for the investigation of key flavor substances in baijiu. Additionally, these findings offer valuable insights into the regulatory mechanisms of aromatic compounds generation.

Determination of antifungal efficacy and phytotoxicity of a unique silica coated porous zinc oxide nanocomposite medium for slow-release agrochemicals.

AIMS: In this study, the antifungal efficacy and phytotoxicity of silica coated porous zinc oxide nanoparticle (SZNP) were analyzed as this nanocomposite was observed to be a suitable platform for slow release fungicides and has the promise to bring down the dosage of other agrochemicals as well. METHODS AND RESULTS: Loading and release kinetics of tricyclazole, a potent fungicide, were analyzed by measuring surface area (SBET) using Brunauer-Emmett-Teller (BET) isotherm and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. The antifungal efficacy of ZnO nanoparticle (ZNP) and SZNP was investigated on two phytopathogenic fungi (Alternaria solani and Aspergillus niger). The morphological changes to the fungal structure due to ZNP and SZNP treatment were studied by field emission-scanning electron microscopy. Nanoparticle mediated elevation of reactive oxygen species (ROS) in fungal samples was detected by analyzing the levels of superoxide dismutase, catalase, thiol content, lipid peroxidation, and by 2,7-dichlorofluorescin diacetate assay. The phytotoxicity of these two nanostructures was assessed in rice plants by measuring primary plant growth parameters. Further, the translocation of the nanocomposite in the same plant model system was examined by checking the presence of fluorescein isothiocyanate tagged SZNP within the plant tissue. CONCLUSIONS: ZNP had superior antifungal efficacy than SZNP and caused the generation of more ROS in the fungal samples. Even then, SZNP was preferred as an agrochemical delivery vehicle because, unlike ZNP alone, it was not toxic to plant system. Moreover, as silica in nanoform is entomotoxic in nature and nano ZnO has antifungal property, both the cargo (agrochemical) and the carrier system (silica coated porous nano zinc oxide) will have a synergistic effect in crop protection.

Biogenic silver nanoparticles from fungal sources: Synthesis, characterization, and antifungal potential.

Nano-biotechnology is quickly developing as an important field of modern research, generating the most promising applications in medicine and agriculture. Biosynthesis of silver nanoparticles using biogenic or green approach provide ecofriendly, clean and effective way out for the synthesis of nanoparticles. The main aim of the study was to synthesize silver nanoparticles (AgNPs) from Aspergillus niger, Aspergillus flavus and Pencillium chrysogenum using a green approach and to test the antifungal activity of these synthesized AgNPs against a variety of pathogenic fungi. The characterization of samples was done by using UV-visible spectroscopy, SEM (scanning electron microscopy), FTIR (Fourier transmission infrared spectroscopy), and XRD (X-ray diffractometry). The investigation confirmed the creation of AgNPs by the fungi Aspergillus niger, Aspergillus flavus and Pencillium chrysogenum, as evidenced by prominent plasmon absorbance bands at 420 and 450 nm.The biosynthesized AgNPs were 80-100 nm in size, asymmetrical in shape and became spherical to sub-spherical when aggregated. Agar well diffusion method was performed to evaluate the antifungal activity of AgNPs against various plant pathogenic fungi. An efficient and strong antifungal activity was shown by these biosynthesized nanoparticles against serious plant pathogenic fungi, viz. Aspergillus terreus, Fusarium oxysporum, Penicillium citrinum, Rhizopus stolonifer and Mucor mucedo. The biosynthesized AgNPs at various concentrations caused significant zone of inhibition in the test fungal pathogens. Silver nanoparticles (AgNPs) biosynthesized from Aspergillus niger at highest concentrations showed maximum zone of inhibition against Penicillium citrinum (19.33 ± 0.57 mm) followed by Rhizopus stolonifer (17.66 ± 0.57), Aspergillus terreus (16.33 ± 1.54 mm), Fusarium oxysporum (14.00 ± 1.00 mm) and Mucor mucedo (13.33 ± 1.15 mm) respectively. Therefore, the findings clearly indicate that silver nanoparticles could play a significant role in managing diverse plant diseases caused by fungi.

Heat resistance of five spoilage microorganisms in a carbonated broth.

Despite their acidic pH, carbonated beverages can be contaminated by spoilage microorganisms. Thermal treatments, before and/or after carbonation, are usually applied to prevent the growth of these microorganisms. However, the impact of CO2 on the heat resistance of spoilage microorganisms has never been studied. A better understanding of the combined impact of CO2 and pH on the heat resistance of spoilage microorganisms commonly found in carbonated beverages might allow to optimize thermal treatment. Five microorganisms were selected for this study: Alicyclobacillus acidoterrestris (spores), Aspergillus niger (spores), Byssochlamys fulva (spores), Saccharomyces cerevisiae (vegetative cells), and Zygosaccharomyces parabailii (vegetative cells). A method was developed to assess the impact of heat treatments in carbonated media on microbial resistance. The heat resistances of the five studied species are coherent with the literature, when data were available. However, neither the dissolved CO2 concentration (from 0 to 7 g/L), nor the pH (from 2.8 to 4.1) have an impact on the heat resistance of the selected microorganisms, except for As. niger, for which the presence of dissolved CO2 reduced the heat resistance. This study improved our knowledge about the heat resistance of some spoilage microorganisms in presence of CO2.

Measurement and prediction of the detachment of Aspergillus niger spores in turbulent flows.

Aspergillus niger (A. niger) spores can induce numerous health problems. Once the airflow-imposed drag force on an A. niger spore exceeds its binding force with the colony, the spore is detached. Turbulent flow may considerably increase the spore detachment. No method is currently available for prediction of the drag force on a spore and its detachment in turbulent flows. This investigation measured the turbulent velocities and detachment of A. niger colonies in a wind tunnel. Computational fluid dynamics (CFD) was employed to model an A. niger unit subjected to turbulent flow blowing. The top 1 % quantile instantaneous velocity of the turbulent flow was specified as the steady entry flow boundary condition for solving the peak velocity distribution and the peak drag forces onto spores. The predicted spore detachment ratios were compared with the measurement data for model validation. The results revealed that the spore detachment ratios with a turbulence intensity of 17 % to 20 % can be twice to triple the ratio with a turbulence intensity of approximately 1 %, when the average velocity for blowing remains the same. The proposed CFD model can accurately predict the detachment ratios of the A. niger spores. ENVIRONMENTAL IMPLICATION: Some people are sensitive to the Aspergillus niger (A. niger) spores, and excessive exposure can cause nasal congestion, skin tingling, coughing, and even asthma. Turbulent flow can considerably increase the spore detachment, due to the increased airflow-imposed drag force on the spores during turbulence. This investigation developed a numerical model to solve for the peak velocity distribution and the peak drag forces onto spores in turbulent flows to predict the spore detachment. With the numerical tool, the airborne fungal spore concentrations would be predictable, which paves a way for intelligent and precise control of fungal aerosol pollution.

Optimized production and characterization of endo-ß-mannanase by Aspergillus niger for generation of prebiotic mannooligosaccharides from guar gum.

Optimized production of Aspergillus niger ATCC 26011 endo-ß-mannanase (ManAn) on copra meal resulted in 2.46-fold increase (10,028 U/gds). Purified ManAn (47 kDa) showed high affinity towards guar gum (GG) as compared to konjac gum and locust bean gum with Km 2.67, 3.25 and 4.07 mg/mL, respectively. ManAn efficiently hydrolyzed GG and liberated mannooligosaccharides (MOS). Changes occurring in the rheological and compositional aspects of GG studied using Differential scanning calorimetry (DSC), Thermal gravimetric analysis (TGA) and X-ray diffraction (XRD) revealed increased thermal stability and crystallinity of the partially hydrolyzed guar gum (PHGG). Parametric optimization of the time and temperature dependent hydrolysis of GG (1% w/v) with 100 U/mL of ManAn at 60 °C and pH: 5.0 resulted in 12.126 mg/mL of mannotetraose (M4) in 5 min. Enhanced growth of probiotics Lactobacilli and production of short chain fatty acids (SCFA) that inhibited enteropathogens, confirmed the prebiotic potential of PHGG and M4.

[Construction and culture condition optimization of a Saccharomyces cerevisiae strain for production of galactitol].

Galactitol, a rare sugar alcohol, has promising potential in the food industry and pharmaceutical field. The available industrial production methods rely on harsh hydrogenation processes, which incur high costs and environmental concerns. It is urgent to develop environmentally friendly and efficient biosynthesis technologies. In this study, a xylose reductase named AnXR derived from Aspergillus niger CBS 513.88 was identified and characterized for the enzymatic properties. AnXR exhibited the highest activity at 25 ℃ and pH 8.0, and it belonged to the NADPH-dependent aldose reductase family. To engineer a strain for galactitol production, we deleted the galactokinase (GAL1) gene in Saccharomyes cerevisiae by using the recombinant gene technology, which significantly reduced the metabolic utilization of D-galactose by host cells. Subsequently, we introduced the gene encoding AnXR into this modified strain, creating an engineered strain capable of catalyzing the conversion of D-galactose into galactitol. Furthermore, we optimized the whole-cell catalysis conditions for the engineered strain, which achieved a maximum galactitol yield of 12.10 g/L. Finally, we tested the reduction ability of the strain for other monosaccharides and discovered that it could produce functional sugar alcohols such as xylitol and arabinitol. The engineered strain demonstrates efficient biotransformation capabilities for galactitol and other functional sugar alcohols, representing a significant advancement in environmentally sustainable production practices.

New reports of pathogen spectrum associated with bulb rot and their interactions during the development of rot in tulip.

Bulb rot, a highly damaging disease of tulip plants, has hindered their profitable cultivation worldwide. This rot occurs in both field and storage conditions posing significant challenges. While this disease has been attributed to a range of pathogens, previous investigations have solely examined it within the framework of a single-pathogen disease model. Our study took a different approach and identified four pathogens associated with the disease: Fusarium solani, Penicillium chrysogenum, Botrytis tulipae, and Aspergillus niger. The primary objective of our research was to examine the impact of co-infections on the overall virulence dynamics of these pathogens. Through co-inoculation experiments on potato dextrose agar, we delineated three primary interaction patterns: antibiosis, deadlock, and merging. In vitro trials involving individual pathogen inoculations on tulip bulbs revealed that B. tulipae,was the most virulent and induced complete bulb decay. Nonetheless, when these pathogens were simultaneously introduced in various combinations, outcomes ranged from partial bulb decay to elongated rotting periods. This indicated a notable degree of antagonistic behaviour among the pathogens. While synergistic interactions were evident in a few combinations, antagonism overwhelmingly prevailed. The complex interplay of these pathogens during co-infection led to a noticeable change in the overall severity of the disease. This underscores the significance of pathogen-pathogen interactions in the realm of plant pathology, opening new insights for understanding and managing tulip bulb rot.

Bioprospecting of endophytic fungi from semidesert candelilla (Euphorbia antisyphilitica Zucc): Potential for extracellular enzyme production.

Endophytic microbial communities colonize plants growing under various abiotic stress conditions. Candelilla (Euphorbia antisyphilitica Zucc.) is a shrub that develops functionally in arid and semi-arid zones of Mexico; these conditions generate an association between the plant and the microorganisms, contributing to the production of enzymes as a defense mechanism for resistance to abiotic stress. The objective of this research was to isolate and identify endophyte fungi of candelilla and bioprospection of these endophytic fungi for enzyme production using candelilla by-products. Fungi were isolated and identified using ITS1/ITS4 sequencing. Their potency index (PI) was evaluated in producing endoglucanase, xylanase, amylase, and laccase. Fermentation was carried out at 30°C for 8 days at 200 rpm, with measurements every 2 days, using candelilla by-products as substrate. All fungi exhibited higher cellulase, amylase, and laccase activities on the 2nd, 6th, and 8th day of fermentation, respectively, of fermentation. The fungus Aspergillus niger ITD-IN4.1 showed the highest amylase activity (246.84 U/mg), the genus Neurospora showed the highest cellulase activity, reaching up to 13.45 FPU/mg, and the strain Neurospora sp. ITD-IN5.2 showed the highest laccase activity (3.46 U/mg). This work provides the first report on the endophytic diversity of E. antisyphilitica and its potential role in enzyme production.