Fungus Aspergillus Research Articles

Asperinsuterpenes A-C from the Fungus Aspergillus insuetus BTBU20220155.

Three new meroterpenoids, asperinsuterpenes A-C (1-3), and eight previously reported natural products, namely asnovolin I (4), (2'E,4'E,6'E)-6-(1'-carboxyocta-2',4',6'-triene)-9-hydroxydrim-7-ene-11,12-olide (5), (2'E,4'E,6'E)-6-(1'-carboxyocta-2',4',6'-triene)-11,12-epoxy-9,11-dihydroxydrim-7-ene (6), cinereain (7), carnequinazolines A and B (8 and 9), carnemycin B (10), and stromemycin (11) were isolated from the fungus Aspergillus insuetus, strain BTBU20220155. The structures of the compounds were determined based on spectroscopic techniques, including 1D and 2D NMR, HRESIMS, and ECD experiments. The in vitro antimicrobial evaluation revealed that compounds 5 and 11 exhibited inhibitory activity against Candida albicans, with minimum inhibitory concentration (MIC) values of 12.5 and 25 μg/mL, respectively. These findings suggest that A. insuetus is a promising source of bioactive natural products with potential applications in antifungal therapy.

Genomics, Proteomics, and Antifungal Activity of Chitinase from the Antarctic Marine Bacterium Curtobacterium sp. CBMAI 2942.

This study aimed to evaluate the genomic profile of the Antarctic marine Curtobacterium sp. CBMAI 2942, as well as to optimize the conditions for chitinase production and antifungal potential for biological control. Assembly and annotation of the genome confirmed the genomic potential for chitinase synthesis, revealing two ChBDs of chitin binding (Chi C). The optimization enzyme production using an experimental design resulted in a 3.7-fold increase in chitinase production. The chitinase enzyme was identified by SDS-PAGE and confirmed through mass spectrometry analysis. The enzymatic extract obtained using acetone showed antifungal activity against the phytopathogenic fungus Aspergillus sp. series Nigri CBMAI 1846. The genetic capability of Curtobacterium sp. CBMAI 2942 for chitin degradation was confirmed through genomic analysis. The basal culture medium was adjusted, and the chitinase produced by this isolate from Antarctica showed significant inhibition against Aspergillus sp. Nigri series CBMAI 1846, which is a tomato phytopathogenic fungus. This suggests that this marine bacterium could potentially be used as a biological control of agricultural pests.

Recent Developments in the Application of Filamentous Fungus Aspergillus oryzae in Ruminant Feed.

The resource-intensive nature of the ruminant farming sector, which has been exacerbated by population growth and increasing pressure to reduce feed antibiotics and growth promoters, has sparked interest in looking for sustainable alternative feed sources to enhance ruminant production efficiency. Edible filamentous fungi, rich in macronutrients like proteins, offer promise in reducing the reliance on conventional protein sources and antimicrobials to improve feed quality and animal performance. The inclusion of single-cell proteins, particularly filamentous fungi, in ruminant feed has long been of scientific and industrial interest. This review focuses on the potential application of the extensively studied Aspergillus oryzae and its fermentation extracts in ruminant nutrition. It provides an overview of conventional ruminant feed ingredients, supplements, and efficiency. Additionally, this review analyzes the re-utilization of organic residues for A. oryzae cultivation and examines the effects of adding fungal extracts to ruminant feed on ruminal digestibility and animal performance, all within a circular bioeconomy framework.

The mitochondrial protein Bcs1A regulates antifungal drug tolerance by affecting efflux pump expression in the filamentous pathogenic fungus Aspergillus fumigatus.

Aspergillus fumigatus is the predominant pathogen responsible for aspergillosis infections, with emerging drug-resistant strains complicating treatment strategies. The role of mitochondrial functionality in fungal resistance to antifungal agents is well-documented yet not fully understood. In this study, the mitochondrial protein Bcs1A, a homolog of yeast Bcs1, was found to regulate colony growth, ion homeostasis, and the response to antifungal drugs in A. fumigatus. Microscopic observations revealed substantial colocalization of Bcs1A-GFP fusion protein fluorescence with mitochondria. Bcs1A deletion compromised colony growth and the utilization of non-fermentable carbon sources, alongside causing abnormal mitochondrial membrane potential and reduced reactive oxygen species production. These findings underscore Bcs1A's vital role in maintaining mitochondrial integrity. Phenotypic analysis and determinations of minimum inhibitory concentrations indicated that the Δbcs1A mutant was more resistant to various antifungal agents, such as azoles, terbinafine, and simvastatin, compared to wild-type strain. RNA sequencing and RT-qPCR analysis highlighted an upregulation of multiple efflux pumps in the Δbcs1A mutant. Furthermore, loss of the principal drug efflux pump, mdr1, decreased azole tolerance in the Δbcs1A mutant, suggesting that Bcs1A's modulated of azoles response via efflux pump expression. Collectively, these results establish Bcs1A as essential for growth and antifungal drug responsiveness in A. fumigatus mediated through mitochondrial regulation.IMPORTANCEDrug resistance presents a formidable obstacle in the clinical management of aspergillosis. Mitochondria are integral to various biochemical pathways, including those involved in fungi drug response, making mitochondrial proteins promising therapeutic targets for drug therapy. This study confirms that Bcs1A, a mitochondrial respiratory chain protein, is indispensable for mitochondrial functionality and multidrug tolerance in Aspergillus fumigatus. Mutation of Bcs1A not only leads to a series of drug efflux pumps upregulated but also shows that loss of the primary efflux pump, mdr1, partial reduction in drug tolerance in the Bcs1A mutant, highlighting that Bcs1A's significant influence on mitochondria-mediated drug resistance.

Nucleophagy in Aspergillus oryzae is Mediated by Autophagosome Formation and Vacuole-Mediated Degradation

We previously reported autophagy-mediated degradation of nuclei, nucleophagy, in the filamentous fungus Aspergillus oryzae. In this study, we examined whether nuclei are degraded as a whole. We generated A. oryzae mutants deleted for orthologs of Saccharomyces cerevisiae YPT7 and ATG15 which are required, respectively, for autophagosome-vacuole fusion and vacuolar degradation of autophagic bodies. Degradation of histone H2B-EGFP under starvation conditions was greatly decreased in the ΔAoypt7 and ΔAoatg15 mutants. Fluorescence and electron microscopic observations showed that autophagosomes and autophagic bodies surrounding the entire nuclei were accumulated in the cytoplasm of ΔAoypt7 and the vacuole of ΔAoatg15, respectively. These results indicate that nuclei are engulfed in the autophagosomes as a whole and transported/released into the vacuolar lumen where they are degraded.

Antimicrobial characteristics of endophytic Aspergillus terreus and acute oral toxicity analysis

BackgroundEndophytic fungi produce biologically robust metabolites suitable for diverse applications, which support the increasing exploration of these fungi. The study aimed to investigate the in vitro antimicrobial properties of the metabolites of endophytic fungus Aspergillus terreus which isolated from the leaves of Psidium guajava plants while the acute oral toxicity was assessed in vivo. ResultsA. terreus (OR125572) was successfully isolated for the first time from P. guajava. The ethyl acetate extract of A. terreus exhibited antibactericidal effects against Enterobacter aerogenes with a minimum inhibitory concentration of 18.75 mg/ml in contrast to 75.00 ± 0.0, 37.50, and 37.50 mg/ml, respectively against Staphylococcus aureus, Escherichia coli, and Bacillus sphaericus were 75.00 ± 0.0, 37.50, and 37.50 mg/ml, respectively. Analysis of the crude extract obtained from A. terreus by GC-MS revealed a total of 32 distinct compounds. The major components included 1,2-benzenedicarboxylic acid, di-iso-octyl ester; hexyl oxecan-2-one and phenol. The acute oral toxicity study found no symptoms of toxicity and no mortality until the 14th d, suggesting that the LD50 value of A. terreus extract might exceed 1 ml/kg. The group receiving 0.5 ml/kg of A. terreus extract experienced a 42.9% increase in body weight, while administration of varying dosages resulted in a significant reduction in MCV levels. There was also a significant increase in the proportion of monocytes across all treated groups. ConclusionsThe study demonstrated the potential of A. terreus as a source of antimicrobial and other bioactive compounds, with relatively low acute toxicity.How to cite: Shehabeldine AM, Abdelaziz AM, Abdel-Maksoud MA, et al. Antimicrobial characteristics of endophytic Aspergillus terreus and acute oral toxicity analysis. Electron J Biotechnol 2024;72. https://doi.org/10.1016/j.ejbt.2024.07.003.

Pseudomonas and Acinetobacter spp. capable of metabolizing aromatics displays multifarious plant growth promoting traits: Insights on strategizing consortium-based application to agro-ecosystems

The persistence and slow rate of natural attenuation of genotoxic and endocrine-disrupting aromatic pollutants has impacted the soil heath of agro-ecologies leading to various health and environmental issues. Ecotoxic-xenobiotic compounds degradation property along with plant growth promoting traits of microbes are beneficial for devising strategies for improved agricultural soil health and its clean-up. Present study assessed the multipartite plant growth promoting-, biocontrol- and niche adaptive- traits of five aromatic degrading soil bacteria viz. Pseudomonas bharatica CSV86T, Pseudomonas sp. C5pp, Pseudomonas sp. PP4, Pseudomonas sp. PPD and Acinetobacter sp. ISP4. Solubilization of rock phosphate (P) and feldspar (K), production of plant growth hormone (auxin; IAA), ammonia, siderophores and ACC deaminase by strain CSV86T, C5pp and PP4 were observed. Similarly, high fusaric acid resistance (MIC: 1–1.2 mg mL−1) and tolerance to salinity (5–7.5 %) was observed. In vitro application of CSV86T, C5pp, PP4 and ISP4 as consortium resulted in significant increase (P < 0.05) in the seedling shoot length (15–37 %), root length (65–150 %) and biomass (30–40 %) of wheat, mung bean and fenugreek. In-soil microcosm assay confirmed the plant growth promoting and phytoprotective ability of this consortium against toxicity of aromatics in contaminated soil. Antifungal activity against phytopathogenic fungi Magnaporthe oryzae and Aspergillus spp., ability to produce lytic enzymes and HCN suggests their biocontrol potential. Four aromatic degrading bacteria (as a consortium) exhibiting plant growth promotion and biocontrol activity could be used as an eco-friendly bioremediator-biofertilizer-biocontrol agent (bioformulation) for restoration of agricultural soil with improved crop productivity.

Isolation of the Endophytic Fungus Aspergillus terreus from a Halophyte (Tetraena qatarensis) and Assessment of Its Potential in Tomato Seedling Protection.

Living in diverse environmentally harsh conditions, the plant exhibits a unique survival mechanism. As a result, the endophytes residing within the plant produce specific compounds that promote the plant's growth and defend it against pathogens. Plants and algae symbiotically harbor endophytes, i.e., microbes and microorganisms living within them. The objective of this study is to isolate endophytic fungi, specifically strains of Aspergillus terreus, from the leaves of the salt-tolerant plant Tetraena qatarensis and to explore the salt tolerance, antagonistic activity, and growth promotion properties. Strain C A. terreus (ON117337.1) was screened for salt tolerance and antagonistic effects. Regarding salt tolerance, the isolate demonstrated the ability to thrive in a concentration of up to 10% NaCl. A. terreus showed inhibitory activity against four fungal phytopathogens, namely Fusarium oxysporum, Alternaria alternata, Colletotrichum gloeosporioides, and Botrytis cinerea. The GC-MS investigation of the fungal (strain C Aspergillus terreus) extract showed the presence of about 66 compounds (secondary metabolites). Secondary metabolites (SMs) are produced, like Hexadecanoic acid, which aids in controlling phytopathogens. Also produced is lovastatin, which is used to treat hypercholesterolemia. Strain C, which showed salinity tolerance and the highest inhibitory activity, was further analyzed for its effect on tomato seed germination under pathogen stress from Fusarium oxysporum. The greenhouse experiment indicated that the fungi increased the length of tomato seedlings and the plant biomass. Therefore, the selected endophytes derived from Tetraena qatarensis were scrutinized for their potential as biocontrol agents, aiming to thwart fungal pathogens and stimulate plant growth. The in vitro and in vivo assessments of strain C (Aspergillus terreus) against Fusarium oxysporum in this investigation indicate the promising role of endophytes as effective biological control agents. Investigating novel bio-products offers a sustainable approach to agriculture, gradually reducing dependence on chemical fungicides.

Microbial Contamination of Food: Probiotics and Postbiotics as Potential Biopreservatives.

Microbial contamination of food and alimentary toxoinfection/intoxication in humans are commonly caused by bacteria such as Salmonella spp., Escherichia coli, Yersinia spp., Campylobacter spp., Listeria monocytogenes, and fungi (Aspergillus, Fusarium). The addition of probiotic cultures (bacterial strains Lactobacillus and Bifidobacterium and the yeast Saccharomyces cerevisiae var. boulardii) to food contributes primarily to food enrichment and obtaining a functional product, but also to food preservation. Reducing the number of viable pathogenic microorganisms and eliminating or neutralizing their toxins in food is achieved by probiotic-produced antimicrobial substances such as organic acids (lactic acid, acetic acid, propionic acid, phenylacetic acid, and phenyllactic acid), fatty acids (linoleic acid, butyric acid, caproic acid, and caprylic acid), aromatic compounds (diacetyl, acetaldehyde, reuterin), hydrogen peroxide, cyclic dipeptides, bacteriocins, and salivabactin. This review summarizes the basic facts on microbial contamination and preservation of food and the potential of different probiotic strains and their metabolites (postbiotics), including the mechanisms of their antimicrobial action against various foodborne pathogens. Literature data on this topic over the last three decades was searched in the PubMed, Scopus, and Google Scholar databases, systematically presented, and critically discussed, with particular attention to the advantages and disadvantages of using probiotics and postbiotics as food biopreservatives.

A new isoprenyl-phenol-type meroterpenoid from mangrove endophytic fungus Aspergillus sp. GXNU-Y65

Asperphenol A (1), a new isoprenyl-phenol-type meroterpenoid, was isolated from the mangrove endophytic fungus Aspergillus sp. GXNU-Y65 together with five known compounds (2-6). All structures were assigned using extensive NMR spectroscopic data and electronic circular dichroism (ECD) calculations. Compounds 1-6 were evaluated for their cytotoxic activity against A549 and T24 human cancer cell lines. Among them, compounds 1 and 5 exhibited moderate inhibitory activities against T24 cancer cell lines with the IC50 values of 26.71 and 43.50 μM, respectively.

Metabolites from the Endophytic Fungus Aspergillus niger Isolated from Clausena anisum-olens and Their Cytotoxicity

Metabolites from the Endophytic Fungus Aspergillus niger Isolated from Clausena anisum-olens and Their Cytotoxicity

Eco-Friendly Synthesis, Characterization, and Biomedical Applications of Biosynthesized Bimetallic Silver-Gold Nanoparticles by Culture Supernatant of Aspergillus niger.

Green synthesis of bimetallic nanoparticles of noble metals is highly desirable in nanomedicine because of their potential use as anticoagulant, thrombolytic and anticancer agents. In this study, it was discovered that the filamentous fungus Aspergillus niger proved effective in producing bimetallic Ag-Au nanoparticles. A. niger culture supernatant was able to produce Ag-AuNPs by reducing the solution of chloroauric acid/silver nitrate (1.0:1.0 mM) within 2 min at 100 °C and pH 8. Experimental Ag-AuNP detection was performed by visually observing the color change to reddish brown. The produced nanoparticles displayed maximal absorbance at 530 nm in UV-vis spectroscopy. According to transmission electron microscopy, most of the nanoparticles were spherical, with a mean diameter of 8-10 nm. The biosynthesis of Ag-AuNPs by A. niger was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive X-ray analytical techniques. Its zeta potential was discovered to be -34.01 mV. The biosynthesized Ag-AuNPs exhibited effective thrombolytic and antiplatelet aggregation actions by totally preventing and dissolving the blood clot which was verified by microscopic examination, amelioration of blood coagulation assays, and carrageenan-induced tail thrombosis model. The findings verified the effectiveness of biosynthesized Ag-AuNPs as a powerful antitumor agent against HepG2 and A549 cell lines with IC50 values of 15.57 and 27.07 μg/mL, respectively. Crystal violet assay validated the cytopathic effects of Ag-AuNPs on A549 and HepG2 cell lines. Therefore, the produced Ag-AuNPs from A. niger are a promising candidate in the management of thrombosis.

Discovery of a Hybrid Molecule with Phytotoxic Activity by Genome Mining, Heterologous Expression, and OSMAC Strategy.

Genome mining in association with the OSMAC (one strain, many compounds) approach provides a feasible strategy to extend the chemical diversity and novelty of natural products. In this study, we identified the biosynthetic gene cluster (BGC) of restricticin, a promising antifungal agent featuring a reactive primary amine, from the fungus Aspergillus sclerotiorum LZDX-33-4 by genome mining. Combining heterologous expression and the OSMAC strategy resulted in the production of a new hybrid product (1), along with N-acetyl-restricticin (2) and restricticinol (3). The structure of 1 was determined by spectroscopic data, including optical rotation and electronic circular dichroism (ECD) calculations, for configurational assignment. Compound 1 represents a fusion of restricticin and phytotoxic cichorin. The biosynthetic pathway of 1 was proposed, in which the condensation of a primary amine of restricticin with a precursor of cichorine was postulated. Compound 1 at 5 mM concentration inhibited the growth of the shoots and roots of Lolium perenne, Festuca arundinacea, and Lactuca sativa with inhibitory rates of 71.3 and 88.7% for L. perenne, 79.4 and 73.0% for F. arundinacea, and 58.2 and 52.9% for L. sativa. In addition, compound 1 at 25 μg/mL showed moderate antifungal activity against Fusarium fujikuroi and Trichoderma harzianum with inhibition rates of 22.6 and 31.6%, respectively. These results suggest that heterologous expression in conjunction with the OSMAC approach provides a promising strategy to extend the metabolite novelty due to the incorporation of endogenous metabolites from the host strain with exogenous compounds, leading to the production of more complex compounds and the acquisition of new physiological functions.

Phytochemical and biological investigation of Astragalus Caprinus L

Backgroundcultivated and wild plants are used to treat different ailments. The Astragalus genus is found in temperate and dry climates; thus, it is found in Egypt and the arab world. Astragalus caprinus has a good amount of bioactive chemicals, which may help explain its therapeutic effects in reducing the risk of consequences from disease.MethodThe phytochemical investigation of the herb and roots of Astragalus caprinus L. included the analytical characterization for the petroleum ether components by GC/MS, unsaponifiable matter (unsap. fraction), and fatty acids (FAME) investigation by GLC analysis. Main flavonoids were chromatographically isolated from ethyl acetate and n-butanol extracts. In vitro antimicrobial activity has been tested against the Gram-positive bacteria Staphylococcus aureus and Streptococcus mutans for different plant extracts, the Gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumonia, the fungus Candida albicans and Aspergillus niger, and the Escherichia coli bacterium. Metabolite cytotoxicity was examined using the MTT assay against HepG-2 (human liver carcinoma) and MCF-7 (breast carcinoma).ResultsIdentifying the important components of the herb and root petroleum ether extracts was achieved. Using column chromatography, luteolin, cosmosiin (apigenin-7-O-glucoside), and cynaroside (luteolin-7-O-glucoside) were separated and identified using UV, NMR, and Mass Spectroscopy. Root extracts displayed potential antimicrobial activity against most of the tested pathogens. Both extracts (herb and roots) were active against the MCF-7 cell line and HepG-2 cell line with IC50 62.5 ± 0.64 and 72.4 ± 2.3 µg/ml, and 75.9 ± 2.5 and 96.8 ± 4.2 µg/ml, respectively.ConclusionAstragalus caprinus seems to be a promising source of bioactive compounds that could potentially aid in preventing disease complications and address common health issues in developing countries. Moreover, the various parts of this plant could be utilized as natural raw materials for producing health-boosting products that could address common health issues in developing countries.

Coconut husk waste products valorization for fabrication of luminescent titanium dioxide NPs as powerful tool for photodecomposition and food born infection: A sustainable strategy.

Fabricating metal oxide nanoparticles has garnered much attention lately because creating safe chemicals, sustainable materials, economic processes, and renewable resources is becoming increasingly important. This research shows how TiO2 nanoparticles (NPs) could be generated in an ecologically responsible way using waste coconut husk with the help of tender coconut. This extract functions as both a reducing agent and a sealing agent. The investigation of TiO2 NPs exploited ultraviolet (UV), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray (EDX) methods. The germicidal properties of TiO2 NPs against food-borne pathogenic strains were studied using the agar well method. Employing Congo red pigment, the photodecomposition behavior was investigated. The TiO2 NPs produced had a crystallite size measuring 16.2nm. The average grain size of the sample, as measured by FE-SEM inspection, falls within the range of 15 to 25 nm. Impressive anti-germ effects against food-borne germs like Gram-positive (Staphylococcus aureus and Listeria monocytogenes), Gram-negative (Salmonella typhimurium and Escherichia coli) bacteria, and fungi (Candida albicans and Aspergillus niger) have been proved by the sustainable fabrication of TiO2 NPs. The catalytic effectiveness of Congo red decreased by 88% after 90 min. The findings suggest that sustainable synthesis of TiO2 NPs is an effective tool for food-borne germicides and photodecomposition behaviors.

Convergent evolution in toxin detection and resistance provides evidence for conserved bacterial–fungal interactions

Microbes rarely exist in isolation and instead form complex polymicrobial communities. As a result, microbes have developed intricate offensive and defensive strategies that enhance their fitness in these complex communities. Thus, identifying and understanding the molecular mechanisms controlling polymicrobial interactions is critical for understanding the function of microbial communities. In this study, we show that the gram-negative opportunistic human pathogen Pseudomonas aeruginosa, which frequently causes infection alongside a plethora of other microbes including fungi, encodes a genetic network which can detect and defend against gliotoxin, a potent, disulfide-containing antimicrobial produced by the ubiquitous filamentous fungus Aspergillus fumigatus. We show that gliotoxin exposure disrupts P. aeruginosa zinc homeostasis, leading to transcriptional activation of a gene encoding a previously uncharacterized dithiol oxidase (herein named as DnoP), which detoxifies gliotoxin and structurally related toxins. Despite sharing little homology to the A. fumigatus gliotoxin resistance protein (GliT), the enzymatic mechanism of DnoP from P. aeruginosa appears to be identical that used by A. fumigatus. Thus, DnoP and its transcriptional induction by low zinc represent a rare example of both convergent evolution of toxin defense and environmental cue sensing across kingdoms. Collectively, these data provide compelling evidence that P. aeruginosa has evolved to survive exposure to an A. fumigatus disulfide-containing toxin in the natural environment.

DETEKSI DAN IDENTIFIKASI PATOGEN CENDAWAN PADA UMBI KENTANG DI SULAWESI SELATAN

Potato (Solanum tuberosum L.) is an important horticultural commodity in Indonesia and the world, but its production has decreased due to attacks by Plant Pest Organisms including fungal pathogens. This study aims to detect and identify fungal pathogens found in potato tubers in potato-producing centers in South Sulawesi. Isolation of the fungus was carried out by the Blotter test method, namely incubating potato tubers on moist filter paper, then the fungal pathogens that appeared were identified. The results showed that the detection and identification of fungal pathogens found in potato tubers in South Sulawesi included the fungal Fusarium sp., Alternaria solani and Aspergillus sp. The percentage of fungal pathogens on potato tubers was dominated by the attack of the fungus Fusarium sp. with an average percentage of 57.5% (medium) in the Enrekang Potato sample, Gowa 62.5% (medium), 52.5% (medium) in the Bantaeng potato tuber sample. Then it was dominated by the fungus Aspergillus sp, on potato tubers Enrekang 47.5% (medium), Gowa 45% (medium) and Bantaeng 42.5% (medium) and the lowest attack rate was the attack of the fungus Alternaria solani (22.5 %) of potato samples from Bantaeng.

Microwave-assisted synthesis and functionalization of nanocrystalline molybdenum trioxide for enhanced antimicrobial and photocatalytic activity

Molybdenum Trioxide nanoparticles (MoO3) were synthesized using ammonium heptamolybdate tetrahydrate [(NH4)6Mo7O24·4H2O] as the primary precursor via the microwave-assisted method and subsequently functionalized with surfactants such as Cetyltrimethylammonium bromide (CTAB), Sodium n-dodecyl sulfate (SDS), and Thioglycolic acid (TGA). The characterization involved X-ray diffraction, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and UV–Visible spectroscopy, revealing hexagonal plate-like morphology, UV absorbance at 202–216 nm with a band gap of 4.2 eV, and a crystalline structure with a 44 nm size calculated by the Scherrer's equation. The synthesized pure (MoO3) and functionalized molybdenum trioxide nanoparticles (FMoO3) were tested for antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Salmonella typhi. Furthermore, MoO3 and FMoO3 also demonstrated enhanced antifungal activity against the fungi Aspergillus niger (Accession No. MZ435922) and Aspergillus fumigatus (Accession No. MZ435863). Photocatalytic experiments demonstrated significant degradation of malachite green dye under UV light irradiation, notably with SDS functionalized MoO3 achieving 98.17 % degradation rate within 20 min, with a linear rate constant of 0.20343 min−1. These findings highlight the potential of MoO3 and FMoO3 nanoparticles as effective antimicrobial agents and their suitability for water purification due to their low toxicity.

Biotransformation of rifampicin by Aspergillus niger and antimicrobial activity of proposed metabolites.

Drug biotransformation studies emerges as an alternative to pharmacological investigations of metabolites, development of new drug candidates with reduced investment and most efficient production. The present study aims to evaluate the capacity of biotransformation of rifampicin by the filamentous fungus Aspergillus niger ATCC 9029. After incubation for 312 h, the drug was metabolized to two molecules: an isomer (m/z 455) and the rifampicin quinone (m/z 821). The monitoring of metabolite formation was performed by high-performance liquid chromatography, followed by their identification through ultra-high-performance liquid chromatography coupled to tandem mass spectrometer. In vitro antimicrobial activity of the proposed metabolites was evaluated against Staphylococus aureus microorganism, resulting in the loss of inhibitory activity when compared with the standards, with minimum inhibitory concentration of 7.5μg/ml. The significant biotransformation power of the ATCC 9029 strain of A. niger was confirmed in this study, making this strain a candidate for pilot studies in fermentation tanks for the enzymatic metabolization of the antimicrobial rifampicin. The unprecedented result allows us to conclude that the prospect of new biotransforming strains in species of anemophilic fungi is a promising choice.

Trilogy of comprehensive treatment of kitchen waste by bacteria-microalgae-fungi combined system: Pretreatment, water purification and resource utilization, and biomass harvesting

Given its profound disservice, a bacteria-microalgae-fungi combined system was designed to treat kitchen waste. Firstly, a new type of microbial agent homemade compound microorganisms (HCM) (composed of Serratia marcescens, Bacillus subtilis and other 11 strains) with relatively high bio-security were developed for pretreating kitchen waste, and HCM efficiently degraded 85.2 % cellulose, 94.3 % starch, and 59.0 % oil. HCM also accomplished brilliantly the initial nutrients purification and liquefaction conversion of kitchen waste. Under mono-culture mode (fungi and microalgae were inoculated separately in the pre - and post-stages) and co-culture mode (fungi and microalgae were inoculated simultaneously in the early stage), microalgae-fungi consortia were then applied for further water purification and resource utilization of kitchen waste liquefied liquid (KWLL) produced in the pretreatment stage. Two kinds of microalgae-fungi consortia (Chlorella sp. HQ and Chlorella sp. MHQ2 form consortia with pellet-forming fungi Aspergillus niger HW8–1, respectively) removed 79.5–83.0 % chemical oxygen demand (COD), 44.0–56.5 % total nitrogen (TN), 90.3–96.4 % total phosphorus (TP), and 64.9–71.0 % NH4+-N of KWLL. What's more, the microalgae-fungi consortia constructed in this study accumulated abundant high-value substances at the same time of efficiently purifying KWLL. Finally, in the biomass harvesting stage, pellet-forming fungi efficiently harvested 81.9–82.1 % of microalgal biomass in a low-cost manner through exopolysaccharides adhesion, surface proteins interaction and charge neutralization. Compared with conventional microalgae-bacteria symbiosis system, the constructed bacteria-microalgae-fungi new-type combined system achieves the triple purpose of efficient purification, resource utilization, and biomass recovery on raw kitchen waste through the trilogy strategy, providing momentous technical references and more treatment systems selection for future kitchen waste treatment.