INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2025
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IF 8.5
Binqiao Ren,Yu Jin,Xiaoxiao Song,Luyang Zhao,Xue Han,Yuying Zhang,Hongzhuang Na
Addressing the critical environmental challenge of hexavalent chromium [Cr(VI)] contamination, understanding the underlying biosorption mechanisms is essential for developing effective and sustainable biosorbents for heavy metal remediation. This study systematically elucidated the chitin-dominated molecular mechanism of Cr(VI) biosorption by Aspergillus niger spores (AS) through comprehensive characterization and mechanistic analysis. Ion chromatography and gas chromatography–mass spectrometry revealed that AS comprises 91.7 % polysaccharides, with chitin presence confirmed via D-glucosamine hydrochloride (13.2 %), establishing the molecular foundation for metal binding. The echinulate morphology provides abundant contact sites, while the chitin-rich composition creates multifunctional binding sites including amide groups from chitin, hydroxyl groups from glucans, and carboxyl groups from proteins. Batch adsorption experiments demonstrated exceptional performance with a maximum adsorption capacity of 106.29 mg g −1 at pH 2.0, following pseudo-second-order kinetics that confirmed chemisorption as the predominant mechanism. DFT calculations validated chitin's dominant role, showing strong binding affinity with a binding energy of 2.47 eV through coordination interactions. Density functional theory calculations validated chitin's dominant role with a binding energy of 2.47 eV, while Fukui function analysis precisely localized reactive sites to amino and hydroxyl functional groups. Based on comprehensive experimental and theoretical evidence, a chitin-dominated three-stage molecular mechanism was proposed: pH-dependent electrostatic interactions facilitate initial contact, chitin mediates Cr(VI) reduction to less toxic Cr(III), and coordination complex formation ensures stable immobilization. This mechanistic understanding provides theoretical guidance for developing chitin-based functional materials and advancing sustainable heavy metal remediation strategies.
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FOOD SCIENCE AND BIOTECHNOLOGY
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2025
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IF 3.1
Tan Jin-Ming,Cui Rui,Hu Teng-Gen,Wu Hong
In order to improve the antifungal activity of natural fungicides to control the fungal contamination on bread products, the synergistic combination of cinnamaldehyde with citral (S CC ) against main bread spoilage fungi ( Aspergillus niger and Penicillium citrinum ) was screened. Compared to the single MICs of cinnamaldehyde and citral, the MICs of them against both fungi were significantly reduced by 74–87% when presented in S CC . In vitro tests demonstrated that S CC completely inhibited the spore germination and mycelial growth of both fungi at its MIC. Mechanistic investigations revealed that S CC caused severe cellular membrane damage and disrupted the intracellular redox homeostasis in both fungi. In situ tests showed S CC significantly extended the shelf life of bread by 9 days without adversely affecting the sensory flavor and quality of the bread. These results indicated that S CC is potential as a natural preservative in baked products.
研究领域:
食品科学
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微生物学
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BIOTECHNOLOGY LETTERS
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2024
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IF 2
Zhang Fei,Wang Xue,Pan Lixia,Wang Zhao,Zheng Jianyong
The α- l -rhamnosidase ( rha 1) gene was homologously expressed in Aspergillus niger strains CCTCC 206047 and CCTCC 206047Δ pyr G, using hygromycin B and auxotrophic as selection markers. The engineered A. niger strains RHA001-1 and RHA003-1 were screened, yielding α- l -rhamnosidase activities of 20.81 ± 0.56 U/mL and 15.35 ± 0.87 U/mL, respectively. The copy numbers of the rha 1 gene in strains RHA001-1 and RHA003-1 were found to be 18 and 14, respectively. Correlation analysis between copy number and enzyme activity in the A. niger strains revealed that α- l -rhamnosidase activity increased with the copy number of the rha 1 gene. Recombinant α- l -rhamnosidase was utilized for the enzymatic debittering of Ougan juice, and its process conditions were optimized. Furthermore, the primary bitter substance neohesperidin (2.22 g/L) in Ougan juice was converted into hesperetin 7-O-glucoside (1.47 g/L) and hesperidin (0.143 g/L). This study presents a novel approach for the production of food-grade α- l -rhamnosidase and establishes a technical foundation for its application in the beverage industry.
研究领域:
生物技术
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食品科学
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酶学
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高影响因子
Frontiers in Microbiology
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2026
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IF 5.8
Heng Zhang,Hua Ni,Mengqi Peng,Tian Chen,Lu Ge,Xueying Zhang,Kai Tian,Yi Sun
BackgroundDematiaceous fungal infections are frequently encountered in clinical practice with no unified treatment. Drug combination reduces drug resistance, and repurposed clinical drugs as synergists show promise in aiding azoles against phaeohyphomycosis.ObjectiveTo investigate the synergistic antifungal effects of docetaxel (DTX) in combination with azoles against dematiaceous fungi and Aspergillus niger, as well as their impact on efflux pump activity.MethodsCLSI M38-A2 microbroth dilution method was used to detect fractional inhibitory concentration index of DTX with posaconazole (POS), itraconazole (ITC), voriconazole (VOR), and isavuconazole (ISA) against 43 fungi (including 24 strains of Exophiala dermatitidis, 7 strains of Exophiala alcalophila, 3 strains of Fonsecaea pedrosoi, 1 strain of Fonsecaea monophora, 1 strain of Exophiala verrucosa and 7 strains of Aspergillus niger). Rhodamine 6G transport efficiency and transcriptional variations of efflux pump genes were determined in strains treated with POS alone or POS combined with DTX.ResultsDTX alone had no antifungal activity. 30/43 (69.8%) strains showed synergy with POS (87.5% E. dermatitidis, 100% A. niger). 7 (16.3%), 3 (7.0%) and 1 (2.3%) strains showed synergy with ITC, VOR and ISA. For strains with POS synergism, DTX treatment significantly suppressed efflux activity and modified the transcription of efflux pump genes.ConclusionThe combined scheme of DTX and POS can significantly reduce the minimum inhibitory concentration of POS and show synergistic antifungal activity, especially significant against E. dermatitidis and A. niger. Its mechanism of action may be related to the reduction of efflux pump activity.
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JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
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2023
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IF 2.8
Yadi Zhou,Qijie Sun,Chao Teng,Mingchun Zhou,Guangsen Fan,Penghui Qu
Corn cobs were fermented with Aspergillus niger to produce soluble dietary fiber (SDF) of high quality and excellent food safety. In this work, the fermentation process was optimized by single-factor test and response surface methodology (RSM). The optimal fermentation conditions were determined to be a material-liquid ratio of 1:30, an inoculum concentration of 11%, a temperature of 32°C, a time of 6 days, and a shaking speed of 200 r/min. Under these conditions, the SDF yield of corn cob increased from 2.34% to 11.92%, and the ratio of soluble dietary fiber to total dietary fiber (SDF/TDF) reached 19.08%, meeting the requirements for high-quality dietary fiber (SDF/TDF of more than 10%). Scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FT-IR) analysis revealed that the fermentation effectively degraded part of cellulose and hemicellulose, resulting in the formation of a loose and porous structure. After fermentation the water swelling capacity, water-holding capacity, and oil-holding capacity of the corn cob SDF were significantly improved and the adsorption capacity of glucose, cholesterol, and nitrite ions all increased by more than 20%. Moreover, the total phenolic content increased by 20.96%, which correlated with the higher antioxidant activity of SDF. Overall, the fermentation of corn cobs by A. niger increased the yield and enhanced the functional properties of dietary fiber (DF) as well.
研究领域:
食品科学
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生物技术
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农业工程
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营养学
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FOOD CHEMISTRY
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2025
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IF 9.8
Minyu Cai,Zhiye Peng,Piqian Xu,Miao Yu,Nanxin Diao,Yong Cao,Sashuang Dong,Xiang Fang
Light-fermented sour tea (ST) was produced by fermenting the Yunnan large-leaf variety of sun-dried green tea (GT) with Aspergillus niger RAF106. The flavor characteristics of both ST and GT were analyzed using GC–MS, HPLC, and LC-MS/MS. The results indicated that 58 volatile compounds were identified after fermentation, including linalool, benzaldehyde, geraniol, and (+)-limonene (odor activity value, OAV > 1). A total of 66 non-volatile compounds were identified, including caffeine, gallic acid, epicatechin, and epigallocatechin (degree over threshold, DoT >1). The content of non-ester catechins, theanine, L* (luminosity), b* (yellowness), theaflavins, and thearubigins significantly increased. The changes in volatile and non-volatile compounds contributed to ST its rich floral aroma, sweet aftertaste, and bright yellow color of the soup. These results enhance the understanding of the flavor characteristics of ST and the effect of A. niger RAF106 fermentation on tea flavor, highlighting the crucial role of microorganisms in tea flavor development.
研究领域:
食品科学
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微生物学
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BIOMEDICAL AND ENVIRONMENTAL SCIENCES
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2019
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IF 1.917
Zhi Na YIN,Wen Jia WU,Chong Zhen SUN,Hui Fan LIU,Wen Bo CHEN,Qi Ping ZHAN,Zhuo Gui LEI,Xuan XIN,Juan Juan MA,Kun YAO,Tian MIN,Meng Meng ZHANG,Hui WU
Objective A strain of Aspergillus niger ( A. niger ), capable of releasing bound phenolic acids from wheat bran, was isolated. This strain was identified by gene sequence identification. The antioxidant and anti-inflammatory capacity of ferulic acid released from wheat bran by this A. niger strain (FA-WB) were evaluated. Methods Molecular identification techniques based on PCR analysis of specific genomic sequences were conducted; antioxidant ability was examined using oxygen radical absorbance capacity (ORAC), cellular antioxidant activity (CAA) assays, and erythrocyte hemolysis assays. RAW264.7 cells were used as a model to detect anti-inflammatory activity. Results The filamentous fungal isolate was identified to be A. niger . ORAC and CAA assay showed that FA-WB had better antioxidant activity than that of the ferulic acid standard. The erythrocyte hemolysis assay results suggested that FA-WB could attenuate AAPH-induced oxidative stress through inhibition of reactive oxy gen species (ROS) generation. FA-WB could significantly restore the AAPH-induced increase in intracellular antioxidant enzyme activities to normal levels as well as inhibit the intracellular malondialdehyde formation. TNF-α, IL-6, and NO levels indicated that FA-WB can inhibit the inflammation induced by lipopolysaccharide (LPS). Conclusion Ferulic acid released from wheat bran by a new strain of A. niger had good anti-inflammatory activity and better antioxidant ability than standard ferulic acid.
研究领域:
食品科学
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微生物学
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营养学
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Frontiers in Microbiology
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2022
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IF 6.064
Youqiang Xu,Huiqin Huang,Hongyun Lu,Mengqin Wu,Mengwei Lin,Chunsheng Zhang,Zhigang Zhao,Weiwei Li,Chengnan Zhang,Xiuting Li,Baoguo Sun
Fatty acid ethyl esters are important flavor chemicals in strong-flavor baijiu. Microorganisms are the main contributors to ester synthesis during baijiu manufacture. However, the ester synthesis was unstable between batches. This was owing to a limited knowledge of the mechanisms for ester synthesis by microorganisms. In this work, a fatty acid ethyl ester synthesizing Aspergillus niger strain CGMCC (China General Microbiological Culture Collection) 3.4309 was identified. The conversion ratios of ethyl valerate, ethyl caproate, ethyl caprylate, and ethyl caprate were 7.87, 29.20, 94.80, and 85.20%, respectively, under the optimized conditions. A comparison of transcriptomes under the initial and optimized ester synthetic conditions indicated that 23 genes were upregulated in transcription level and encoded enzymes with potential abilities for ester synthesis. Eleven of the enzymes were expressed, and three of them, numbered An605, An1097, and An3131, showed the ability to catalyze fatty acid ethyl ester synthesis under aqueous phase, with capric acid as the preferred substrate. The possible enzymatic catalytic mechanism was proposed based on homology modeling and molecular docking. This study reported for the first time that A. niger showed the ability to efficiently catalyze the synthesis of short- and medium-chain fatty acid ethyl esters in aqueous phase, identified the key enzymes, and analyzed the basic enzymatic properties. This is helpful to promote the application of related microorganisms and enzyme resources in the baijiu industry.
研究领域:
微生物学
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生物化学
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食品科学
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2025
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IF 8.5
Qihui Lu,Hui Liao,Zedong Jiang,Yanbing Zhu,Yijuan Han,Lijun Li,Hui Ni,Qingbiao Li
Glycosylation plays a critical role in regulating activity, stability, and correct folding of enzymes. In this study, recombinant Aspergillus niger α-L-rhamnosidase (r-Rha1) was employed to explore the impact of glycosylation in Pichia pastoris on the enzymatic properties and protein folding . β-elimination reaction and deglycosylase treatment assays demonstrated that r-Rha1 undergoes primarily N-glycosylation. The deglycosylated r-Rha1 was prepared in two ways: treating with Endoglycosidase F 1 after expression (referred to as r-Rha1- vitro ), or inhibiting intracellular glycosylation using tunicamycin (referred to as r-Rha1- vivo ). Deglycosylation resulted in a 0.22-fold decrease in activity for r-Rha1- vitro and due to its slower turnover rate, r-Rha1- vivo showed a 0.73-fold decrease in activity. r-Rha1- vitro maintained the similar optimal temperature as r-Rha1, r-Rha1- vivo displayed a 10 °C lower optimal temperature. Compared to the decreased extent of r-Rha1- vitro in t 1/2 at 55 °C, 60 °C, and 65 °C and T m , chemical interferent deglycosylation in vivo showed a more profound impact on r-Rha1. Analyses based on circular dichroism, fluorescence spectroscopy, and differential scanning calorimetry revealed significant changes in the structure and thermodynamic stability of r-Rha1- vivo , accounting for its marked decline in activity and stability. The significant and unpredictable structure changes of r-Rha1- vivo proved the essential role of glycosylation for appropriate folding in P. pastoris .
研究领域:
生物化学
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分子生物学
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
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IF 7.7
Leyi Yu,Tiantian Wang,Bin Wang,Li Pan
Aspergillus niger is a cell factory widely used in industries to produce proteases, organic acids, drugs, and other substances. The hyphal morphology of A. niger is a complex differentiated elongated tubular structure, which limits its basic research and application. In this study, the mpkA , bck1 , steC , and Tpk2 genes were successfully deleted using a quick way to knock out genes based on the RNP (Ribonucleoprotein) complex. The study showed that the knockout of mpkA and bck1 kinase gene strains resulted in smaller, denser colonies, short rod-shaped hypha, and a significant increase in glucoamylase secretion. The mechanism of short hypha formation and high protein production for A. niger is the cell wall integrity signaling (CWIS) pathway. The CWIS pathway passed through the bck1 - mkkA - mpkA tertiary kinase to deliver phosphorylation signals to the rlmA transcription factor, which regulated the expression of the cell wall synthesis gene agsA , thus regulating hyphal morphology. The mpkA kinase regulated the expression of the transcription factor amyR , which affected the expression of the genes glaA and amyA , thus enhancing the expression of proteins in A. niger . This study provides a strategy for the regulation of hyphal morphology and promotes the application of A. niger in industrial production.
研究领域:
微生物学
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生物技术
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分子生物学
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
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IF 3.131
Hao Yang,Hanlin Ding,Xiaonuo Zhang,Xuegang Luo,Yu Zhang
In this study, a new surface-modified biobased composite was obtained by modifying the surface of fungal mycelium microspheres (FHMs) with polydopamine (PDA). A. niger mycelium/PDA microspheres (AM/PDA microspheres) were used as a highly efficient adsorbent for the removal of U(VI) ions. This study examined the effects of the initial pH, ionic strength, and electrolyte ions on the U(VI) adsorption capacity of the AM/PDA microspheres. The results confirmed that U(VI) was successfully adsorbed on the AM/PDA microspheres. We compared their adsorption capacity with that of other adsorbents, and the adsorption rate and adsorption capacity of the AM/PDA microspheres were found to be higher than those of the other adsorbents. Equilibrium was achieved after 300 min, and the AM/PDA microspheres had a maximum adsorption capacity of 250.70 mg/g. We aimed not only to investigate the factors that affect the adsorption process but also to provide a new mycelial-based composite adsorbent for U(VI)-contaminated water.
研究领域:
环境科学
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生物材料学
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POSTHARVEST BIOLOGY AND TECHNOLOGY
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2026
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IF 7.3
Ying Xie,Ke Ding,Saiqing Xu,Xinbei Qiao,Qi Tang,Yang Shan,Shenghua Ding
Aspergillus niger is the principal postharvest spoilage fungus of high-moisture fruits, causing substantial food waste and economic losses. Carvacrol, a plant‑derived phenolic, exhibits significant antifungal potential against A. niger , while the specific target and molecular mechanism requires further elucidation, and poor solubility hinders application. Here, we developed a carvacrol nanoemulsion (CN) stabilized by OSA-modified starch nanoparticles to overcome this limitation and elucidated the antifungal mechanism against A. niger . Compared to ethanol-dissolved carvacrol (CE), CN exhibited superior antifungal efficacy with nano-sized droplets enhancing cell membrane penetration, resulting in a lower MIC (156.25 mg/L) than CE (312.5 mg/L). CN induced more severe hyphal membrane and ultrastructural damage, as well as severe ultrastructural damage, ROS accumulation, electrolyte leakage, reduced ergosterol and ATP contents, and elevated MDA levels in A. niger . Furthermore, in vivo experiments demonstrated that CN reduced the lesion diameter of representative fruits (kiwifruit and strawberries) during storage. Integrated transcriptomics and proteomics revealed that CN profoundly disrupted the metabolic homeostasis of A. niger . Specifically, while A. niger upregulated ABC transporters to efflux carvacrol, mitochondrial oxidative phosphorylation downregulation caused ATP deficiency. Meanwhile, CN treatment suppressed key genes/proteins in alanine, aspartate, glutamate metabolism, and propanoate metabolism, blocking nitrogen assimilation, nucleotide synthesis, and toxic intermediate detoxification. The oxidative damage, biosynthetic arrest, and impaired DNA replication and repair functions induced by CN resulted in membrane damage and macromolecule leakage, ultimately causing irreversible cell death. This study elucidated the antifungal mechanism of carvacrol at physiological and molecular levels, providing a theoretical basis for controlling postharvest decay using nanoemulsion technology.
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