Construction of transcript regulation mechanism prediction models based on binding motif environment of transcription factor AoXlnR in Aspergillus oryzae.

DNA-binding transcription factors (TFs) play a central role in transcriptional regulation mechanisms, mainly through their specific binding to target sites on the genome and regulation of the expression of downstream genes. Therefore, a comprehensive analysis of the function of these TFs will lead to the understanding of various biological mechanisms. However, the functions of TFs in vivo are diverse and complicated, and the identified binding sites on the genome are not necessarily involved in the regulation of downstream gene expression. In this study, we investigated whether DNA structural information around the binding site of TFs can be used to predict the involvement of the binding site in the regulation of the expression of genes located downstream of the binding site. Specifically, we calculated the structural parameters based on the DNA shape around the DNA binding motif located upstream of the gene whose expression is directly regulated by one TF AoXlnR from Aspergillus oryzae, and showed that the presence or absence of expression regulation can be predicted from the sequence information with high accuracy ([Formula: see text]-1.0) by machine learning incorporating these parameters.

Nutritional and sensory parameters of amazake from the recycling of stale bread.

Stale bread is a waste product with a potential to be recycled. One way to manage this waste material is to process it by fermentation for the purpose of food production. This paper proposes the use of stale wheat and rye bread as ingredients in amazake, a liquid dessert traditionally obtained from rice by fermentation with the koji mould Aspergillus oryzae, followed by liquefaction by the action of fungal enzymes. The stale bread was introduced instead of rice at both the koji stage (wheat bread) and the liquefaction stage (wheat and rye bread). The resulting products had an extended volatile compound profile, from 5 to 15 compounds identified, and modified sensory parameters, compared to the traditional version. Amazake containing bread had an increased protein content, from 1.10 to 6.4 g/100 g, and were more abundant in dietary fibre (up to a maximum of 1.8 g/100 g), additionally enriched with a soluble fraction. The proposed procedure of obtaining of new formula amazake can be directly applied in households to reduce the amount of discarded bread. Due to its simplicity, it also has the potential for further modification in terms of production scale and product parameters.

Screening, identification, and characterization of molds for brewing rice wine: Scale-up production in a bioreactor.

Rice wine, well known for its unique flavor, rich nutritional value, and health benefits, has potential for extensive market development. Rhizopus and Aspergillus are among several microorganisms used in rice wine brewing and are crucial for determining rice wine quality. The strains were isolated via Rose Bengal and starch as a combined separation medium, followed by oenological property and sensory evaluation screening. The strain exhibiting the best performance can be screened using the traditional rice wine Qu. The strains YM-8, YM-10, and YM-16, which exhibited strong saccharification and fermentation performance along with good flavor and taste, were obtained from traditional rice wine Qu. Based on ITS genetic sequence analysis, the YM-8, YM-10, and YM-16 strains were identified as Rhizopus microsporus, Rhizopus arrhizus, and Aspergillus oryzae. The optimum growth temperature of each of the three strains was 30°C, 32°C, and 30°C, and the optimum initial pH was 6.0, 6.5, and 6.5, respectively. The activities of α-amylase, glucoamylase, and protease of YM-16 were highest at 220.23±1.88, 1,269.04±30.32, and 175.16±1.81 U/g, respectively. The amino acid content of rice wine fermented in a 20-L bioreactor with the three mold strains was higher than that of the control group, except for arginine, which was significantly lower than that of the control group. The total amino acid content and the total content of each type of amino acid were ranked as YM-16 > YM-8 > YM-10 > control group, and the amino acid content varied greatly among the strains. The control group had a higher content, whereas YM-8 and YM-16 had lower contents of volatile aroma components than the control group and had the basic flavor substances needed for rice wine, which is conducive to the formation of rice wine aroma. This selected strain, YM-16, has strong saccharification and fermentation ability, is a rich enzyme system, and improves the flavor of rice wine, thereby demonstrating its suitability as a production strain for brewing.

Stimulating Novel and Bioactive Metabolite Production by Cocultivation of Two Fungi─Aspergillus oryzae and Epicoccum dendrobii.

Fungi produce various bioactive secondary metabolites (SMs) as protective and weaponized tools to enhance survival in shared ecological niches. By mimicking a competitive ecosystem, cocultivation has been proven to be particularly successful in stimulating SM discovery. Here, we reported the identification of four novel metabolites, epiclactones A and B, epioxochromane and aoergostane, from the coculture of two biotechnologically important strains, Aspergillus oryzae and Epicoccum dendrobii. Transcriptome and metabolome analyses revealed widespread silent gene activation during fungal-fungal interaction. The majority of differentially expressed gene clusters were summarized for both strains. Based on these highly activated biosynthetic pathways, we suggested that a bidirectional chemical defense occurred under cocultivation. E. dendrobii enhanced the production of the spore inhibitor, fumigermin. Moreover, A. oryzae highly accumulated the antifungal agent kojic acid with a yield of up to 1.10 g/L. This study provides an excellent example for the discovery of hidden natural products by cocultivation.

[Aspergillus flavus/oryzae Arthritis of the Knee Joint: First Case in Türkiye]. / Diz Ekleminde Gelisen Aspergillus flavus/oryzae Artriti: Türkiye'de Ilk Olgu.

Aspergillus species are common hyphal fungi. In addition to allergies and mycotoxicosis, Aspergillus species can cause various infections known as aspergillosis. Aspergillosis of the respiratory tract, central nervous system, skin and soft tissues is well described. However, musculoskeletal infections due to invasive aspergillosis are not well described. Fungal joint infection due to invasive aspergillosis is a rare form of septic arthritis. In this case report, a patient who admitted to our hospital for liver transplantation and developed knee joint arthritis caused by Aspergillus flavus/Aspergillus oryzae during this process was presented. A 28-year-old male patient with autoimmune hepatitis was admitted to hospital with decompensated liver cirrhosis and encephalopathy. The patient, who was awaiting an emergency liver transplant, developed pain, swelling and limitation of movement in his right knee and appropriate consultations and tests were requested. Three joint fluid cultures taken one day apart and nine days later were positive for fungal growth. Macroscopic examination of the mould growth and microscopic examination with lactophenol cotton blue suggested a species belonging to the A.flavus complex and the isolate was identified as A.flavus/A.oryzae by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-TOF MS) (EXS 2600, Zybio, China). As a result of ITS gene sequencing, the species was determined to be A.oryzae. As cases have been reported where A.flavus and A.oryzae species could not be distinguished by ITS gene sequencing, the pathogen was defined as A.flavus/oryzae. The patient died of liver disease during treatment with amphotericin B. There are few cases of arthritis caused by Aspergillus species in the literature. Aspergillus species found in joint infections are, Aspergillus fumigatus, A.flavus, Aspergillus niger and Aspergillus terreus species complexes, in order of frequency. A.flavus and A.oryzae are closely related. They are difficult to distinguish by conventional methods, MALDI-TOF MS or ITS region sequencing, which is commonly used for genus/species identification in fungi. The number of Aspergillus arthritis cases is low and the identification methods applied to the species reported as causative agents in most studies can identify at the species complex level. In addition, it can be assumed that species not previously reported as causative agents may be encountered as a result of developments in identification methods. In the few publications in the literature where A.flavus complex was reported as the causative agent of joint infections, it seems possible that some of the agents may be A.flavus and some may be A.oryzae, since the agents were identified at the complex level. There are a limited number of cases in the literature where A.oryzae is the causative agent, particularly in the respiratory tract. A PubMed search using the keywords "A.oryzae infections, arthritis, osteomyelitis" did not reveal any literature on joint infections caused by A.oryzae.

Three-Step Enzymatic Remodeling of Chitin into Bioactive Chitooligomers.

Here we describe a complex enzymatic approach to the efficient transformation of abundant waste chitin, a byproduct of the food industry, into valuable chitooligomers with a degree of polymerization (DP) ranging from 6 to 11. This method involves a three-step process: initial hydrolysis of chitin using engineered variants of a novel fungal chitinase from Talaromyces flavus to generate low-DP chitooligomers, followed by an extension to the desired DP using the high-yielding Y445N variant of ß-N-acetylhexosaminidase from Aspergillus oryzae, achieving yields of up to 57%. Subsequently, enzymatic deacetylation of chitooligomers with DP 6 and 7 was accomplished using peptidoglycan deacetylase from Bacillus subtilis BsPdaC. The innovative enzymatic procedure demonstrates a sustainable and feasible route for converting waste chitin into unavailable bioactive chitooligomers potentially applicable as natural pesticides in ecological and sustainable agriculture.

Live cell imaging of ß-tubulin mRNA reveals spatiotemporal expression dynamics in the filamentous fungus Aspergillus oryzae.

In filamentous fungi, microtubules are important for polar growth and morphological maintenance and serve as rails for intracellular trafficking. The molecular mechanisms associated with microtubules have been analyzed. However, little is known about when and where tubulin, a component of microtubules, is biosynthesized in multinuclear and multicellular filamentous fungi. In this study, we visualized microtubules based on the enhanced green fluorescence protein (EGFP)-labeled α-tubulin and ß-tubulin mRNA tagged by the EGFP-mediated MS2 system in living yellow Koji mold Aspergillus oryzae cells in order to understand the spatiotemporal production mechanism of tubulin. We found that mRNA of btuA, encoding for ß-tubulin, localized at dot-like structures through the apical, middle and basal regions of the hyphal cells. In addition, some btuA mRNA dots showed microtubule-dependent motor protein-like dynamics in the cells. Furthermore, it was found that btuA mRNA dots were decreased in the cytoplasm just before mitosis but increased immediately after mitosis, followed by a gradual decrease. In summary, the localization and abundance of ß-tubulin mRNA is spatiotemporally regulated in living A. oryzae hyphal cells.

Glucose-induced endocytic degradation of the maltose transporter MalP is mediated through ubiquitination by the HECT-ubiquitin ligase HulA and its adaptor CreD in Aspergillus oryzae.

In the filamentous fungus Aspergillus oryzae, large amounts of amylolytic enzymes are inducibly produced by isomaltose, which is converted from maltose incorporated via the maltose transporter MalP. In contrast, the preferred sugar glucose strongly represses the expression of both amylolytic and malP genes through carbon catabolite repression. Simultaneously, the addition of glucose triggers the endocytic degradation of MalP on the plasma membrane. In budding yeast, the signal-dependent ubiquitin modification of plasma membrane transporters leads to selective endocytosis into the vacuole for degradation. In addition, during glucose-induced MalP degradation, the homologous of E6AP C-terminus-type E3 ubiquitin ligase (HulA) is responsible for the ubiquitin modification of MalP, and the arrestin-like protein CreD is required for HulA targeting. Although CreD-mediated MalP internalization occurs in response to glucose, the mechanism by which CreD regulates HulA-dependent MalP ubiquitination remains unclear. In this study, we demonstrated that three (P/L)PxY motifs present in the CreD protein are essential for functioning as HulA adaptors so that HulA can recognize MalP in response to glucose stimulation, enabling MalP internalization. Furthermore, four lysine residues (three highly conserved among Aspergillus species and yeast and one conserved among Aspergillus species) of CreD were found to be necessary for its ubiquitination, resulting in efficient glucose-induced MalP endocytosis. The results of this study pave the way for elucidating the regulatory mechanism of MalP endocytic degradation through ubiquitination by the HulA-CreD complex at the molecular level.

Submerged fermentation of lentil protein isolate and its impact on protein functionality, nutrition, and volatile profiles.

Fermentation of pulses as a clean processing technique has been reported to have a favorable impact on the functional and nutritional quality of the starting materials. Compared to commonly fermented pulses such as peas and chickpeas, limited information is available on the effect of fermentation on lentils, especially when using a high protein isolate (>80% protein) as compared to seeds or flours. Therefore, in the present work, lentil protein isolate was used as a feedstock for submerged fermentation with Aspergillus niger, Aspergillus oryzae, or Lactobacillus plantarum. After 48 h, the samples showed increased protein content with enhanced solubility and oil-holding capacity. Controlled fermentation, as opposed to spontaneous fermentation, maintained the high foaming capacity; however, all fermented samples had lower foam and emulsion stabilizing properties and reduced water-holding capacity compared to the control. The fermented proteins were also less digestible, possibly due to an increase in phenolics and saponins. New volatile compounds were identified in fermented samples that show promise for improved sensory attributes. Significant differences were observed in specific quality attributes depending on the microbial strain used. Further research is required to better understand the fermentative metabolism of microbial communities when provided high-protein lentil ingredients as growth substrates. PRACTICAL APPLICATION: Fermented lentil protein isolate has promising flavor profiles that may improve its sensory properties for food application.

Aspergillus oryzae ß-D-galactosidase immobilization on glutaraldehyde pre-activated amino-functionalized magnetic mesoporous silica: Performance, characteristics, and application in the preparation of sesaminol.

Aspergillus oryzae ß-D-galactosidase (ß-Gal) efficiently hydrolyzes sesaminol triglucoside into sesaminol, which has higher biological activity. However, ß-Gal is difficult to be separate from the reaction mixture and limited by stability. To resolve these problems, ß-Gal was immobilized on amino-functionalized magnetic nanoparticles mesoporous silica pre-activated with glutaraldehyde (Fe3O4@mSiO2-ß-Gal), which was used for the first time to prepare sesaminol. Under the optimal conditions, the immobilization yield and recovered activity of ß-Gal were 57.9 ± 0.3 % and 46.5 ± 0.9 %, and the enzymatic loading was 843 ± 21 Uenzyme/gsupport. The construction of Fe3O4@mSiO2-ß-Gal was confirmed by various characterization methods, and the results indicated it was suitable for heterogeneous enzyme-catalyzed reactions. Fe3O4@mSiO2-ß-Gal was readily separable under magnetic action and displayed improved activity in extreme pH and temperature conditions. After 45 days of storage at 4 °C, the activity of Fe3O4@mSiO2-ß-Gal remained at 92.3 ± 2.8 %, which was 1.29 times than that of free enzyme, and its activity remained above 85 % after 10 cycles. Fe3O4@mSiO2-ß-Gal displayed higher affinity and catalytic efficiency. The half-life was 1.41 longer than free enzymes at 55.0 °C. Fe3O4@mSiO2-ß-Gal was employed as a catalyst to prepare sesaminol, achieving a 96.7 % conversion yield of sesaminol. The excellent stability and catalytic efficiency provide broad benefits and potential for biocatalytic industry applications.

Study on the Skincare Effects of Red Rice Fermented by Aspergillus oryzae In Vitro.

Red rice, a variety of pigmented grain, serves dual purposes as both a food and medicinal resource. In recent years, we have witnessed an increasing interest in the dermatological benefits of fermented rice extracts, particularly their whitening and hydrating effects. However, data on the skincare advantages derived from fermenting red rice with Aspergillus oryzae remain sparse. This study utilized red rice as a substrate for fermentation by Aspergillus oryzae, producing a substance known as red rice Aspergillus oryzae fermentation (RRFA). We conducted a preliminary analysis of RRFA's composition followed by an evaluation of its skincare potential through various in vitro tests. Our objective was to develop a safe and highly effective skincare component for potential cosmetic applications. RRFA's constituents were assessed using high-performance liquid chromatography (HPLC), Kjeldahl nitrogen determination, the phenol-sulfuric acid method, and enzyme-linked immunosorbent assay (ELISA). We employed human dermal fibroblasts (FB) to assess RRFA's anti-aging and antioxidative properties, immortalized keratinocytes (HaCaT cells) and 3D epidermal models to examine its moisturizing and reparative capabilities, and human primary melanocytes (MCs) to study its effects on skin lightening. Our findings revealed that RRFA encompasses several bioactive compounds beneficial for skin health. RRFA can significantly promote the proliferation of FB cells. And it markedly enhances the mRNA expression of ECM-related anti-aging genes and reduces reactive oxygen species production. Furthermore, RRFA significantly boosts the expression of Aquaporin 3 (AQP3), Filaggrin (FLG), and Hyaluronan Synthase 1 (HAS1) mRNA, alongside elevating moisture levels in a 3D epidermal model. Increases were also observed in the mRNA expression of Claudin 1 (CLDN1), Involucrin (IVL), and Zonula Occludens-1 (ZO-1) in keratinocytes. Additionally, RRFA demonstrated an inhibitory effect on melanin synthesis. Collectively, RRFA contains diverse ingredients which are beneficial for skin health and showcases multifaceted skincare effects in terms of anti-aging, antioxidant, moisturizing, repairing, and whitening capabilities in vitro, highlighting its potential for future cosmetic applications.

Phosphatidylcholine levels regulate hyphal elongation and differentiation in the filamentous fungus Aspergillus oryzae.

Filamentous fungi are eukaryotic microorganisms that differentiate into diverse cellular forms. Recent research demonstrated that phospholipid homeostasis is crucial for the morphogenesis of filamentous fungi. However, phospholipids involved in the morphological regulation are yet to be systematically analyzed. In this study, we artificially controlled the amount of phosphatidylcholine (PC), a primary membrane lipid in many eukaryotes, in a filamentous fungus Aspergillus oryzae, by deleting the genes involved in PC synthesis or by repressing their expression. Under the condition where only a small amount of PC was synthesized, A. oryzae hardly formed aerial hyphae, the basic structures for asexual development. In contrast, hyphae were formed on the surface or in the interior of agar media (we collectively called substrate hyphae) under the same conditions. Furthermore, we demonstrated that supplying sufficient choline to the media led to the formation of aerial hyphae from the substrate hyphae. We suggested that acyl chains in PC were shorter in the substrate hyphae than in the aerial hyphae by utilizing the strain in which intracellular PC levels were controlled. Our findings suggested that the PC levels regulate hyphal elongation and differentiation processes in A. oryzae and that phospholipid composition varied depending on the hyphal types.

Double knockout of two target genes via genome co-editing using a nitrate transporter gene nrtA and a putative thiamine transporter gene thiI as selectable markers in Aspergillus oryzae.

Genome co-editing technology is effective in breeding filamentous fungi for applications in the fermentation industry, achieving site-directed mutagenesis, the status of non-genetically modified organisms (non-GMOs), and wild-type-like growth phenotype. Prior to this study, thiI gene was found as a selectable marker for such genome co-editing in the filamentous fungus Aspergillus oryzae, while it cannot be reused via marker recycling. Therefore, we aimed to identify another marker gene to knock out another target gene via genome co-editing in A. oryzae. In this study, we focused on the membrane transporter gene nrtA (AO090012000623), which promotes uptake of nitrate (NO3-). It is known that, in nrtA knockout strain, chlorate (ClO3-), an analog of nitrate with antifungal activity, cannot be imported into the cytosol, which enables the mutant to grow in the presence of chlorate. Based on this information, knockout of the target gene wA was attempted using both nrtA- and wA-specific single-guide RNAs via genome co-editing with KClO3 supplementation in A. oryzae laboratory strain RIB40 and industrial strain KBN616. Resultantly, wA knockout mutant was generated, and nrtA was identified as a selectable marker. Moreover, this genome co-editing system using nrtA was compatible with that using thiI, and thus, a double knockout mutant of two target genes wA and yA was constructed in RIB40 while maintaining non-GMO status and wild-type-like growth. As nrtA homologs have been found in several industrial Aspergillus species, genome co-editing using homolog genes as selectable markers is plausible, which would contribute to the widespread breeding of industrial strains of Aspergilli.

Molecular simulations guide immobilization of lipase on nest-like ZIFs with regulatable hydrophilic/hydrophobic surface.

The catalytic performance of immobilized lipase is greatly influenced by functional support, which attracts growing interest for designing supports to achieve their promotive catalytic activity. Many lipases bind strongly to hydrophobic surfaces where they undergo interfacial activation. Herein, the behavioral differences of lipases with distinct lid structures on interfaces of varying hydrophobicity levels were firstly investigated by molecular simulations. It was found that a reasonable hydrophilic/hydrophobic surface could facilitate the lipase to undergo interfacial activation. Building on these findings, a novel "nest"-like superhydrophobic ZIFs (ZIFN) composed of hydrophobic ligands was prepared for the first time and used to immobilize lipase from Aspergillus oryzae (AOL@ZIFN). The AOL@ZIFN exhibited 2.0-folds higher activity than free lipase in the hydrolysis of p-Nitrophenyl palmitate (p-NPP). Especially, the modification of superhydrophobic ZIFN with an appropriate amount of hydrophilic tannic acid can significantly improve the activity of the immobilized lipase (AOL@ZIFN-TA). The AOL@ZIFN-TA exhibited 30-folds higher activity than free lipase, and still maintained 82% of its initial activity after 5 consecutive cycles, indicating good reusability. These results demonstrated that nanomaterials with rational arrangement of the hydrophilic/hydrophobic surface could facilitate the lipase to undergo interfacial activation and improve its activity, displaying the potential of the extensive application.

Identification and enzymatic properties of arginine decarboxylase from Aspergillus oryzae.

Aspergillus oryzae spores, when sprinkled onto steamed rice and allowed to propagate, are referred to as rice "koji." Agmatine, a natural polyamine derived from arginine through the action of arginine decarboxylase (ADC), is abundantly produced by solid state-cultivated rice koji of A. oryzae RIB40 under low pH conditions, despite the apparent absence of ADC orthologs in its genome. Mass spectrometry imaging revealed that agmatine was accumulated inside rice koji at low pH conditions, where arginine was distributed. ADC activity was predominantly observed in substrate mycelia and minimally in aerial mycelia. Natural ADC was isolated from solid state-cultivated A. oryzae rice koji containing substrate mycelia, using ammonium sulfate fractionation, ion exchange, and gel-filtration chromatography. The purified protein was subjected to sodium dodecyl sulfate poly-acrylamide gel electrophoresis (SDS-PAGE), and the detected peptide band was digested for identification by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The gene AO090102000327 of strain RIB40 was identified, previously annotated as phosphatidylserine decarboxylase (PSD), and encoded a 483-amino acid peptide. Recombinant protein encoded by AO090102000327 was expressed in Escherichia coli cells cultivated at 20°C, resulting in the detection of 49 kDa and 5 kDa peptides. The protein exhibited pyruvoyl-dependent decarboxylase activity, favoring arginine over ornithine and showing no activity with phosphatidylserine. The gene was designated Ao-adc1. Ao-ADC1 expression in rice koji at pH 4-6 was confirmed through western blotting using the anti-Ao-ADC1 serum. These findings indicate that Ao-adc1 encodes arginine decarboxylase involved in agmatine production.IMPORTANCEGene AO090102000327 in A. oryzae RIB40, previously annotated as a PSD, falls into a distinct clade when examining the phylogenetic distribution of PSDs. Contrary to the initial PSD annotation, our analysis indicates that the protein encoded by AO090102000327 is expressed in the substrate mycelia area of solid state-cultivated A. oryzae rice koji and functions as an arginine decarboxylase (ADC). The clade to which Ao-ADC1 belongs includes three other Ao-ADC1 paralogs (AO090103000445, AO090701000800, and AO090701000802) that presumably encode ADC rather than PSDs. Regarding PSD, AO090012000733 and AO090005001124 were speculated to be nonmitochondrial and mitochondrial PSDs in A. oryzae RIB40, respectively.

Biosynthesis of Enfumafungin-type Antibiotic Reveals an Unusual Enzymatic Fusion Pattern and Unprecedented C-C Bond Cleavage.

Enfumafungin-type antibiotics, represented by enfumafungin and fuscoatroside, belong to a distinct group of triterpenoids derived from fungi. These compounds exhibit significant antifungal properties with ibrexafungerp, a semisynthetic derivative of enfumafungin, recently gaining FDA's approval as the first oral antifungal drug for treating invasive vulvar candidiasis. Enfumafungin-type antibiotics possess a cleaved E-ring with an oxidized carboxyl group and a reduced methyl group at the break site, suggesting unprecedented C-C bond cleavage chemistry involved in their biosynthesis. Here, we show that a 4-gene (fsoA, fsoD, fsoE, fsoF) biosynthetic gene cluster is sufficient to yield fuscoatroside by heterologous expression in Aspergillus oryzae. Notably, FsoA is an unheard-of terpene cyclase-glycosyltransferase fusion enzyme, affording a triterpene glycoside product that relies on enzymatic fusion. FsoE is a P450 enzyme that catalyzes successive oxidation reactions at C19 to facilitate a C-C bond cleavage, producing an oxidized carboxyl group and a reduced methyl group that have never been observed in known P450 enzymes. Our study thus sets the important foundation for the manufacture of enfumafungin-type antibiotics using biosynthetic approaches.

Profile of Phenolic Compounds and Antioxidant Activity of Celery (Apium graveolens) Juices Obtained from Pulp after α-Amylase Treatment from Aspergillus oryzae.

The purpose of this study was to determine the content of certain phenolic compounds, antioxidant activity, pressing efficiency, extract content, and sugars in celeriac juices obtained from the pulp after α-amylase treatment from Aspergillus oryzae. The test material consisted of peeled and unpeeled celery pulp kept at a temperature of 25 °C with and without the enzyme for a period of 30 and 60 min. The juices obtained from them were analyzed for the content of selected phenolic acids and flavonoids using the UPLC-PDA-ESI-MS/MS method, for antioxidant activity measured using the ABTS˙+ and DPPH˙ method, and for the total polyphenol content using the F-C method. Additionally, the juice pressing efficiency, the extract content using the refractometer method, and the sugar content using the HPLC method were checked. Significantly higher antioxidant activity, pressing yield, and average content of caffeic acid glucoside, quinic acid, kaempferol-3,7-di-O-glucoside, and chrysoeriol-7-O-apiosylglucoside were obtained in juices from peeled celery. Maceration of the pulp with amylase resulted in a significant reduction in antioxidant activity compared to control samples. An is-total increase of 17-41% in total flavonoid content was observed in all juices tested after treatment with the enzyme for 30 and 60 min, and the phenolic acid content increased by 4-41% after treatment of the pulp with amylase for 60 min. The 60 min holding of the pulp at 25 °C, including with the enzyme, was shown to decrease the antioxidant activity and the content of quinic acid, ferulic acid, and chrysoriol-7-O-apiose-glucoside in the juices tested compared to the samples held for 30 min, while the content of other phenolic acids and flavonoids increased. In addition, after 60 min of enzymatic maceration, the pressing yield of the juices increased.

How Fungi Biosynthesize 3-Nitropropanoic Acid: The Simplest yet Lethal Mycotoxin.

We uncovered the biosynthetic pathway of the lethal mycotoxin 3-nitropropanoic acid (3-NPA) from koji mold Aspergillus oryzae. The biosynthetic gene cluster (BGC) of 3-NPA, which encodes an amine oxidase and a decarboxylase, is conserved in many fungi used in food processing, although most of the strains have not been reported to produce 3-NPA. Our discovery will lead to efforts that improve the safety profiles of these indispensable microorganisms in making food, alcoholic beverages, and seasoning.

Proteomics analysis of enzyme systems and pathway changes during the moromi fermentation of soy sauce mash.

BACKGROUND: During the brewing of soy sauce, the conversion of multiple substances is driven by various microorganisms and their secreted enzyme systems. Soy sauce mash is an important source of enzyme systems during moromi fermentation, but the changes of enzyme systems in soy sauce mash during moromi fermentation are poorly understood. In order to explore the predominant enzyme systems existing during moromi fermentation and to explain the characteristics of the enzyme system changes, an enzymatic activities assay and 4D-label-free proteomics analysis were conducted on soy sauce mash at different stages of fermentation. RESULTS: The activities of hydrolytic enzymes in soy sauce mash decreased continuously throughout the fermentation process, while most of the characteristic physicochemical substances in soy sauce mash supernatant had already accumulated at the early stage of fermentation. Four hydrolytic enzymes were found to be positively correlated with important physicochemical indexes by principal component analysis and Pearson correlation analysis. The proteomics analysis revealed three highly upregulated enzymes and two enzymes that were present in important metabolic pathways throughout the fermentation process. Furthermore, it was found that Aspergillus oryzae was able to accumulate various nutrients in the soy sauce mash by downregulating most of its metabolic pathways. CONCLUSION: Enzymes present with excellent properties during the moromi fermentation period could be obtained from these results. Meanwhile, the characterization of the metabolic pathways of microorganisms during the moromi fermentation period was revealed. The results provide a basis for more scientific and purposeful improvement of moromi fermentation in the future. © 2024 Society of Chemical Industry.

Changing the polyphenol composition and enhancing the enzyme activity of sorghum grain by solid-state fermentation with different microbial strains.

BACKGROUND: Solid-state fermentation (SSF) has been widely used in the processing of sorghum grain (SG) because it can produce products with improved sensory characteristics. To clarify the influence of different microbial strains on the SSF of SG, especially on the polyphenols content and composition, Lactiplantibacillus plantarum, Saccharomyces cerevisiae, Rhizopus oryzae, Aspergillus oryzae, and Neurospora sitophila were used separately and together for SSF of SG. Furthermore, the relationship between the dynamic changes in polyphenols and enzyme activity closely related to the metabolism of polyphenols has also been measured and analyzed. Microstructural changes observed after SSF provide a visual representation of the SSF on the SG. RESULTS: After SSF, tannin content (TC) and free phenolic content (FPC) were decreased by 56.36% and 23.48%, respectively. Polyphenol oxidase, ß-glucosidase and cellulase activities were increased 5.25, 3.27, and 45.57 times, respectively. TC and FPC were negatively correlated with cellulase activity. A positive correlation between FPC and xylanase activity after 30 h SSF became negative after 48 h SSF. The SG surface was fragmented and porous, reducing the blocking effect of cortex. CONCLUSION: Cellulase played a crucial role in promoting the degradation of tannin (antinutrient) and phenolic compounds. Xylanase continued to release flavonoids while microbial metabolism consumed them with the extension of SSF time. SSF is an effective way to improve the bioactivity and processing characteristics of SG. © 2024 Society of Chemical Industry.