Showing papers on "Aspergillus niger published in 2019"
TL;DR: Proteomic analysis of fungal secretomes that significantly improved biomass degradation showed that the presence of proteins belonging to a putative LPMO family previously identified by genome analysis and awaiting experimental demonstration of activity was found, named AA16.
Abstract: Lignocellulosic biomass is considered as a promising alternative to fossil resources for the production of fuels, materials and chemicals. Efficient enzymatic systems are needed to degrade the plant cell wall and overcome its recalcitrance. A widely used producer of cellulolytic cocktails is the ascomycete Trichoderma reesei, but this organism secretes a limited set of enzymes. To improve the saccharification yields, one strategy is to upgrade the T. reesei enzyme cocktail with enzymes produced by other biomass-degrading filamentous fungi isolated from biodiversity. In this study, the enzymatic cocktails secreted by five strains from the genus Aspergillus (Aspergillus japonicus strains BRFM 405, 1487, 1489, 1490 and Aspergillus niger strain BRFM 430) were tested for their ability to boost a T. reesei reference cocktail for the saccharification of pretreated biomass. Proteomic analysis of fungal secretomes that significantly improved biomass degradation showed that the presence of proteins belonging to a putative LPMO family previously identified by genome analysis and awaiting experimental demonstration of activity. Members of this novel LPMO family, named AA16, are encountered in fungi and oomycetes with life styles oriented toward interactions with plant biomass. One AA16 protein from Aspergillus aculeatus (AaAA16) was produced to high level in Pichia pastoris. LPMO-type enzyme activity was demonstrated on cellulose with oxidative cleavage at the C1 position of the glucose unit. AaAA16 LPMO was found to significantly improve the activity of T. reesei CBHI on cellulosic substrates. Although Aspergillus spp. has been investigated for decades for their CAZymes diversity, we identified members of a new fungal LPMO family using secretomics and functional assays. Properties of the founding member of the AA16 family characterized herein could be of interest for use in biorefineries.
119 citations
TL;DR: By overexpressing a single gene, it is possible to significantly improve the citric acid secretion capability of a moderately producing parental strain and demonstrate the importance of the cellular transport system for an efficient production of metabolites.
88 citations
TL;DR: It is demonstrated that the aromatic quality of HQGRW may be critically influenced by the microbiota in traditional fermentation starters, and the development of novel defined starter cultures for improving the aromaticquality of HQ GRW is contributed to.
87 citations
TL;DR: The impact of systems biology on the citric acid molecular regulatory mechanisms, the advances in metabolic engineering strategies for enhancingcitric acid production and the development and application of CRISPR/Cas9 systems for genome editing in A. niger are summarized.
Abstract: Citric acid is the world’s largest consumed organic acid and is widely used in beverage, food and pharmaceutical industries. Aspergillus niger is the main industrial workhorse for citric acid production. Since the release of the genome sequence, extensive multi-omic data are being rapidly obtained, which greatly boost our understanding of the citric acid accumulation mechanism in A. niger to a molecular and system level. Most recently, the rapid development of CRISPR/Cas9 system facilitates highly efficient genome-scale genetic perturbation in A. niger. In this review, we summarize the impact of systems biology on the citric acid molecular regulatory mechanisms, the advances in metabolic engineering strategies for enhancing citric acid production and discuss the development and application of CRISPR/Cas9 systems for genome editing in A. niger. We believe that future systems metabolic engineering efforts will redesign and engineer A. niger as a highly optimized cell factory for industrial citric acid production.
66 citations
TL;DR: The results reveal that A. niger was found to be the most successful strain for the removal of heavy metals from the contaminated soil with maximum bioaccumulation efficiency and Aspergillus fumigatus (M3Ai) exhibited the maximum bioleaching capacity.
Abstract: Remediation of heavy metals, other than microbial bioleaching method, is expensive and unsuitable for large contaminated areas. The current study was aimed to isolate, identify, and test the potential of indigenous fungal strains for heavy metal removal from contaminated soil. A total of three metallotolerant fungal strains, i.e., Aspergillus niger (M1DGR), Aspergillus fumigatus (M3Ai), and Penicillium rubens (M2Aii), were isolated and identified by phenotyping and genotyping from heavy metal–contaminated soil of Hattar Industrial Estate, Pakistan. A. niger was found to be the most successful strain for the removal of heavy metals from the contaminated soil with maximum bioaccumulation efficiency of 98% (Cd) and 43% (Cr). In contrast, A. fumigatus showed comparatively low but still considerable bioleaching potential, i.e., 79% and 69% for Cd and Cr removal, respectively. Maximum metal uptake efficiency, i.e., 0.580 mg g−1 and 0.152 mg g−1 by A. niger strain was noticed for Cd and Cr with Czapek yeast extract (CYE) and Sabouraud dextrose broth (SDB) media, respectively. A. fumigatus (M3Ai) exhibited the maximum bioleaching capacity (0.40 mg g−1) for Cr with CYE medium. The results reveal that A. niger M1DGR and A. fumigatus M3Ai could be used to develop new strategies to remediate soil contaminated with heavy metals (Cd and Cr) through either in situ or ex situ mycoremediation.
65 citations
TL;DR: It was confirmed that A. niger has the higher Pb tolerance compared with P. oxalicum, and the enhanced biosorption via forming new border of cell wall prevents the transportation of Pb (II) into hypha.
Abstract: Environmental microorganisms have been widely applied in heavy metal remediation. This study explored the mechanisms of lead tolerance of two typical filamentous fungi, Aspergillus niger and Penicillium oxalicum. It is shown that the mechanisms of reducing Pb toxicity by these two fungi have three major pathways. The secreted oxalic acid can react with Pb (II) to form insoluble Pb minerals, primarily lead oxalate. Then, the enhanced biosorption via forming new border of cell wall prevents the transportation of Pb (II) into hypha. In addition, the fungal activity could be maintained even at high Pb concentration due to the intracellular accumulation. It was confirmed that A. niger has the higher Pb tolerance (up to 1500 mg l-1 Pb level) compared with P. oxalicum (up to 1000 mg l-1 ). Meanwhile, Pb levels below 1000 mg l-1 partially stimulate the bioactivity of A. niger, which was confirmed by its elevated respiration (from 53 to 63 mg C l-1 medium h-1 ). This subsequently enhanced microbial functions of A. niger to resist Pb toxicity. A better understanding of Pb tolerance of these two fungi sheds a bright future of applying them to remediate lead-contaminated environments.
64 citations
TL;DR: In this paper, the antifungal activities and mechanisms of tea tree oil (TTO) and its main components were investigated as potential substitutes for synthetic preservatives, and α-terpineol and terpene-4-ol exhibited the greatest effectiveness at inhibiting mycelium growth and spore germination.
60 citations
TL;DR: The first report on the production of lipase from Aspergillus niger MTCC 872 using tri-substrate mixture of rice husk, cottonseed cake, and red gram husk is reported, which signifies usage of agro-industrial residues as substrates for enzyme production by solid-state fermentation process as an effective alternative to submerged fermentation for industrial applications.
Abstract: Lipases are serine hydrolases that degrade triglycerides, an attribute that treasures wide applications in biodiesel production, detergent, chemical industries, etc. The most sought after the application is in the high quality and economical production of biodiesel under mild reaction conditions and simplified product separation. For the said application, fungal lipases are ideal catalysts that could effectively catalyze esterification and transesterification reactions with their specific ability to release fatty acids from 1, 3 positions of acylglycerols. In the present work, to facilitate bulk synthesis, lipase production using Aspergillus niger MTCC 872 was studied by solid-state fermentation (SSF). The chosen fungal strain was evaluated for lipase production using a mixture of agro-industrial substrates viz. rice husk, cottonseed cake, and red gram husk in various combinations at flask level. Tri-substrate mixture (rice husk, cottonseed cake, and red gram husk) combined in the ratio of 2:1:1 has shown the maximum lipase activity 28.19 U/gds at optimum cultivation conditions of temperature 40 °C, moisture content 75% (v/w), pH 6.0 and initial spore concentration of 5.4 million spores per mL. Further studies were performed for scale-up of lipase from flask level to lab scale using tray fermenter. Lipase activity was found to be 24.38 U/gds and 21.62 U/gds for 100 g and 1000 g substrate respectively. This is the first report on the production of lipase from Aspergillus niger MTCC 872 using tri-substrate mixture of rice husk (RH), cottonseed cake (CSC), and red gram husk (RGH). Moreover, comparison between individual, binary, and tri-substrate mixture was carried out for which the highest lipase activity was observed for tri-substrate mixture. In addition, comparable results were found when scale-up was performed using tray fermenter. Thus, the current work signifies usage of agro-industrial residues as substrates for enzyme production by solid-state fermentation process as an effective alternative to submerged fermentation for industrial applications.
56 citations
TL;DR: In in vitro study using filter papers as model, the suppressive effect of biosynthesized silver and zinc oxide nanoparticles (NPs) on A. niger A2 bioderteriorant activity was evaluated and treatments enhanced tensile strength and preserved the original morphology of paper fibers.
Abstract: Historic cultural heritage and archival manuscripts have a significant importance worldwide and efforts should be considered to preserve such property for as long as possible. The current study aimed to establish a non-toxic, and eco-friendly conservation strategy for retarding paper biodeterioration. To this end, fungal isolates associated with the biodeteriorated paper manuscripts of the historical book “DESCRIPTION DE L´EGYPTE” dating back to 1823 A.D were isolated. These isolates were identified as Asperigllus niger, Aspergillus flavus, Penicillium chrysogenum and Alternaria alternata and then evaluated for cellulolytic activities. Amongst them, Aspergillus niger A2 exhibited the highest cellulase activity. In in vitro study using filter papers as model, the suppressive effect of biosynthesized silver and zinc oxide nanoparticles (NPs) on A. niger A2 bioderteriorant activity was evaluated. Biosynthesized Ag-NPs and ZnO-NPs were characterized by UV-Vis spectroscopy, X-ray diffraction patterns (XRD), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FT-IR). Color changes, tensile strength, FT-IR-spectroscopy, and scanning electron microscopy of NPs-treated papers were examined. Treatments with 2 mM Ag-NPs and 2 mM ZnO-NPs exhibited the best conservation effect on treated papers and alleviated cellulose degradation. Furthermore, this treatments enhanced tensile strength and preserved the original morphology of paper fibers. These results introduced a potential approach for historical documents conservation against fungal biodeterioration through NPs sprays. It can be also used for preparing anti-biodeterioration paper for expected manuscripts uses.
56 citations
TL;DR: A meta-analysis of 155 transcriptomics experiments generated co-expression networks for 9,579 genes of the A. niger genome and uncovered four transcription factors involved in secondary metabolite synthesis, which were used to activate production of multiple natural products.
Abstract: A significant challenge in our understanding of biological systems is the high number of genes with unknown function in many genomes. The fungal genus Aspergillus contains important pathogens of humans, model organisms, and microbial cell factories. Aspergillus niger is used to produce organic acids, proteins, and is a promising source of new bioactive secondary metabolites. Out of the 14,165 open reading frames predicted in the A. niger genome only 2% have been experimentally verified and over 6,000 are hypothetical. Here, we show that gene co-expression network analysis can be used to overcome this limitation. A meta-analysis of 155 transcriptomics experiments generated co-expression networks for 9,579 genes (∼65%) of the A. niger genome. By populating this dataset with over 1,200 gene functional experiments from the genus Aspergillus and performing gene ontology enrichment, we could infer biological processes for 9,263 of A. niger genes, including 2,970 hypothetical genes. Experimental validation of selected co-expression sub-networks uncovered four transcription factors involved in secondary metabolite synthesis, which were used to activate production of multiple natural products. This study constitutes a significant step towards systems-level understanding of A. niger, and the datasets can be used to fuel discoveries of model systems, fungal pathogens, and biotechnology.
53 citations
TL;DR: Indigenous metallotolerant fungal strains A. fumigatus and A. terreus (M7), isolated in this study, could be used (ex situ or in situ) to remediate soils contaminated with Pb and Hg.
Abstract: Bioleaching of heavy metals from industrial contaminated soil using metallotolerant fungi is the most efficient, cost-effective, and eco-friendly technique. In the current study, the contaminated soil samples from Hattar Industrial Estate revealed a total lead (Pb) and mercury (Hg) concentration of 170.90 mg L−1 and 26.66 mg L−1, respectively. Indigenous metallotolerant fungal strains including Aspergillus niger M1, Aspergillus fumigatus M3, Aspergillus terreus M6, and Aspergillus flavus M7 were isolated and identified by pheno- and genotyping. A. fumigatus and A. flavus of soil sample S1 showed higher efficiency for Pb removal (99.20% and 99.30%, respectively), in SDB medium. Likewise, A. niger and A. terreus of soil sample S2 showed higher efficiency for Hg removal (96% and 95.50%, respectively), in YPG medium. Furthermore, the maximum uptake efficiency for Pb removal (8.52 mg g−1) from soil sample S1 was noticed for A. fumigatus in YPG medium, while the highest uptake efficiency (4.23 mg g−1) of A. flavus M2 strain was observed with CYE medium. Similarly, the maximum uptake efficiency of 0.41 mg g−1 and 0.44 mg g−1 for Hg removal from soil sample S2 was found for A. niger and A. terreus strains, respectively, in CYE medium. Thus, in order to address the major issue of industrial waste pollution, indigenous fungal strains A. fumigatus (M1) and A. terreus (M7), isolated in this study, could be used (ex situ or in situ) to remediate soils contaminated with Pb and Hg.
TL;DR: Olorofim shows encouraging in vitro activity against cryptic species of Aspergillus that can be hard to treat with current antifungal therapies, and is warranted in order to assess its efficacy.
Abstract: Objectives To investigate the in vitro activity of olorofim (F901318), a novel broad-spectrum antifungal agent, against 150 strains belonging to 16 different cryptic species of Aspergillus by EUCAST and CLSI methodologies. Methods Olorofim, amphotericin B, micafungin, posaconazole and voriconazole were tested against cryptic species belonging to Aspergillus fumigatus complex (n = 57), Aspergillus ustus complex (n = 25), Aspergillus niger complex (n = 20), Aspergillus flavus complex (n = 20), Aspergillus circumdati complex (n = 15) and Aspergillus terreus complex (n = 13) using EUCAST and CLSI methodologies for broth microdilution susceptibility testing of antifungal agents. Results Olorofim was the only drug with activity against all cryptic species of Aspergillus tested, including the multiresistant species Aspergillus lentulus, Aspergillus fumigatiaffinis and Aspergillus calidoustus. Geometric means of MICs for olorofim were lower (0.017, 0.015 and 0.098 mg/L, respectively, for EUCAST; and 0.015, 0.015 and 0.048 mg/L, respectively, for CLSI) than for amphotericin B (4.438, 12.699 and 0.554 mg/L, respectively, for EUCAST; and 0.758, 1.320 and 0.447 mg/L, respectively, for CLSI), voriconazole (2.549, 2.297 and 5.856 mg/L, respectively, for EUCAST; and 2.071, 1.741 and 5.657 mg/L, respectively, for CLSI) and posaconazole (0.307, 0.308 and 12.996 mg/L, respectively, for EUCAST; and 0.391, 0.215 and 9.514 mg/L, respectively, for CLSI). Conclusions Olorofim shows encouraging in vitro activity against cryptic species of Aspergillus that can be hard to treat with current antifungal therapies. Further studies are warranted in order to assess its efficacy.
TL;DR: In this article, the authors investigated the influence of chicken feather peptone (CFP) for citric acid production in Aspergillus niger and found that CFP increased the production of the acid.
Abstract: Citric acid is a commercially important organic acid with a wide range of applications. To reduce the cost of producing citric acid, sugar beet molasses and chicken feather peptone (CFP) were used as the sole carbon and nitrogen sources, respectively for submerged citric acid biosynthesis using Aspergillus niger. To improve the citric acid production, the parental isolate of A. niger MO-25 was improved by mutation using ethidium bromide. Citric acid production using molasses was significantly affected by CFP concentrations (1–6 g/L). The maximum citric acid concentration was determined at 4 g/L CFP and 168 h. When CFP compared to commercial peptones (casein and bacto), the highest citric acid production was obtained with CFP. Furthermore, the addition of KH2PO4 (0.15 g/L) enhanced citric acid production (68.8 g/L). These results suggested that sugar beet molasses supplemented with CFP as organic nitrogen and mineral salt sources could be utilized for the economical and efficient production of citric acid. This is the first study to investigate the influence of CFP for citric acid production.
TL;DR: In this article, the authors examined changes in phenolic compounds and the antioxidant activity of Mexican mango seed in the bioprocess of solid-state fermentation (SSF) with the fungus Aspergillus niger GH1.
Abstract: This study examines changes in phenolic compounds and the antioxidant activity of Mexican mango seed in the bioprocess of solid-state fermentation (SSF) with the fungus Aspergillus niger GH1. The chemical composition and evaluation of mango seed as solid fermentation substrate support was also evaluated. Because of the chemical composition and the rapid growth of the fungus, mango seed is a suitable material to be used in SSF. The results showed that SSF of mango seed mobilized the polyphenolic compounds and improved the nutraceutical properties. The total phenol content in ethanol extract increased (p
TL;DR: This study is the first to specify causative antifungal VOCs using a correlation between growth inhibition of P. italicum by the bacterium grown on each of the four media vs. the relative abundance of individual V OCs.
TL;DR: Ferulic acid released from wheat bran by a new strain of Aspergillus niger had good anti-inflammatory activity and better antioxidant ability than standard ferulic acid.
TL;DR: Comparative data are highlighted where the similarities and the real differences of these two processes occur, which involves various aspects of medium composition, metabolic regulation and compartmentation, transcriptional regulation, and gene evolution to facilitate further investigations of citric acid and itaconic acid accumulation.
Abstract: Citric acid production by Aspergillus niger and itaconic acid production by Aspergillus terreus are two major examples of technical scale fungal fermentations based on metabolic overflow of primary metabolism. Both organic acids are formed by the same metabolic pathway, but whereas citric acid is the end product in A. niger, A. terreus performs two additional enzymatic steps leading to itaconic acid. Despite of this high similarity, the optimization of the production process and the mechanism and regulation of overflow of these two acids has mostly been investigated independently, thereby ignoring respective knowledge from the other. In this review, we will highlight where the similarities and the real differences of these two processes occur, which involves various aspects of medium composition, metabolic regulation and compartmentation, transcriptional regulation, and gene evolution. These comparative data may facilitate further investigations of citric acid and itaconic acid accumulation and may contribute to improvements in their industrial production.
TL;DR: Nitrogen fixer Azotobacter SR-4 and phosphorus solubilizer Asphergillus Niger were produced and observed to be efficient biofertilzers and a significant increase in yield parameters were observed when they were evaluated on Bottle gourd and okra.
TL;DR: Key properties of glucose oxidase can be modified in vitro by laboratory evolution, which may have remarkable economic importance as well as enhance thermostability and catalytic efficiency.
TL;DR: Results demonstrated that this modified Cre-loxP system is a powerful tool for genetic engineering in A. niger, which has the potential to be genetically modified as a viable aciduric platform strain to produce high levels of various organic acids.
Abstract: The filamentous fungus Aspergillus niger is widely used in the biotechnology industry for the production of chemicals and enzymes. Engineering of this valuable organism to improve its productivity is currently hampered by the lack of efficient genetic tools. Here, a Cre-loxP-based system for gene editing in A. niger was developed and its application in construction of A. niger cell factories to produce various organic acids was explored. Two established inducible systems, the xylanase A gene promoter Pxln and Tet-on system, were examined for driving cre expression and thus selection marker hyh deletion. Under inducing conditions, the efficiency of loxP site-specific recombination in the strain with cre driven by Pxln is about 2%, while cre driven by Tet-on system is about 34% which was used as the platform strain for further genetic engineering. As a proof of application of this system, strains containing different copies of oxaloacetate acetylhydrolase–encoding gene (oahA) were constructed, and the resultant strain S428 showed as high as 3.1-fold increase in oxalic acid production. Furthermore, an efficient malate-producing strain was generated through four-step genetic manipulation (oahA deletion, pyc, mdh3 and C4-dicarboxylate transporter gene c4t318 insertion). The resultant strain S575 achieved a titer 120.38 g/L malic acid with the flask culture, and a titer 201.24 g/L malic acid in fed-batch fermentation. These results demonstrated that this modified Cre-loxP system is a powerful tool for genetic engineering in A. niger, which has the potential to be genetically modified as a viable aciduric platform strain to produce high levels of various organic acids.
TL;DR: This study aimed to optimize an integrated simple process for citric acid production using Spanish-style green olive processing wastewaters enriched with sugars from white grape pomace and the robust Aspergillus niger B60 to support the potential for clustering the respective enterprises in a biorefinery plant forcitric acid fermentation.
TL;DR: The fungal inhibition mechanism of bioactive CuO/C nanocomposite was discussed in this research article and the particular high antifungal performance was found against Aspergillus niger while compare to As pergillus flavus fungal strain.
TL;DR: Corrosion behavior of 7075-T6 aluminum alloy in a high salinity environment containing Aspergillus niger was investigated using high-performance liquid chromatography tandem mass spectrometry, gas chromatography, surface analysis and electrochemical measurement.
TL;DR: Kinetic investigation of bioconversion of crude glycerol into malic acid using Aspergillus niger was studied using Monod, Mosser, and Haldane-Andrew models and response surface methodology and artificial neural network.
TL;DR: This work provides novel and efficient approaches for improving GOD thermostability, and the obtained variant constructed by the computational strategy can be used as an efficient biocatalyst for GA production at industrially viable conditions.
TL;DR: The potential of fungal co-culture as an environmentally-friendly method to enhance Leptosphaerulina sp.
TL;DR: Evidence is provided for the control of black Aspergillus growth in grape and OTA detoxifying by the use of autochthones LAB strains having antifungal effect and probiotic potential.
Abstract: The aim of this study was to isolate lactic acid bacteria from two varieties of grape bunch cultivated in Tunisia (cardinal and red-globe) in order to assess their ability to inhibit the growth of their most widespread contaminant, Aspergillus niger aggregats and Aspergillus carbonarius. Antifungal activity of 18 isolates was investigated using overlay technique; selected isolates were than identified using 16s rDNA sequence analysis. Isolates with antifungal activities were screened out and studied for their probiotic properties using in vitro tests (tolerance to simulated gastric jus, bile salts, hydrophobicity properties).The most efficient strain was also investigated for its ability to reduce the concentration of ochratoxin A (OTA) on liquid medium. Determination of OTA content in media was released using HPLC analysis. Selected strains (RG7B) (C11C) and (RG8A) showing a good antifungal activities against Aspergillus niger aggregats and Aspergillus carbonarius were identified as Pediococcus pentosaceus and Lactobacillus plantarum, respectively. Pediococcus pentosaceus (RG7B) showed promising potential probiotic characteristics and had a high ability for OTA removal after 48 h of incubation in both MRS and PBS media. The OTA removal percentage was significantly higher in MRS than in PBS media (84 and 25%, respectively). This study provides evidence for the control of black Aspergillus growth in grape and OTA detoxifying by the use of autochthones LAB strains having antifungal effect and probiotic potential.
TL;DR: In this paper, Aspergillus niger was used to leach out Al, Fe, Ti, Ni, V from spent fluid catalytic cracking catalyst (SFCCC), and the results showed that the acidity in OSBp suggests acidolysis as the leading leaching mechanism.
Abstract: The present study evaluates biopotential of Aspergillus niger and chemical potency of strong organic and inorganic acids to leach out Al, Fe, Ti, Ni, V from spent fluid catalytic cracking catalyst (SFCCC). One-step bioleaching (OSBp) and spent medium bioleaching (SMB) of metals at 1%, 3% and 5% pulp densities by Aspergillus niger was investigated. Leaching efficiency was found to be maximum at 1% pulp density and decreased as the pulp density increased to 5%, this is perhaps due to the inhibitory effect of some metals existing in SFCCC. The maximum amount of Al, Fe, Ti, Ni, and V leached from SFCCC are 1388 mg/L, 28 mg/L, 6 mg/L, 2 mg/L and 8 mg/L of leaching medium respectively. Biologically produced leaching agents other than citric, gluconic and oxalic acids produced by Aspergillus niger solely contributed to 50%, 32%, and 42% of Al, Ti and V leaching efficiencies respectively. The acidic pH in OSBp suggests acidolysis as the leading leaching mechanism. The citric acid is the chief leaching agent produced by Aspergillus niger in the presence of SFCCC while gluconic acid dominated in SMB (in the absence of SFCCC). OSBp yielded higher leaching efficiencies of all the metals compared to SMB. OSBp dominated Al, Ti, and V leaching compared to all organic and inorganic acid leaching. While OSBp of Fe was comparable to inorganic acid leaching and oxalic acid leaching is suggested for Ni leaching. The competitive Al, Ti, V and Fe leaching and being environmentally friendly, OSBp of metals from SFCCC by Aspergillus niger is recommended.
TL;DR: The biologic lixiviation of Cu, Ag and Au from printed circuit boards (PCB) of mobile phones by three strains of Aspergillus niger, Candida orthopsilosis, Sphingomonas sp.
Abstract: Electronic waste (E-Waste) is consumed at high speed in the world. These residues contain metals that increase their price each year, generating new research on the ability of microorganisms to recover the metals from these wastes. Therefore, this work evaluated the biologic lixiviation of Cu, Ag and Au from printed circuit boards (PCB) of mobile phones by three strains of Aspergillus niger, Candida orthopsilosis, Sphingomonas sp. and their respective consortia, in addition to leaching with citric acid. The microorganisms were cultured in mineral media with 0.5 g of PCB, and the treatments with 1M citric acid were added the same amount of PCB. All treatments were incubated for 35 days at room temperature. The results showed that Sphingomonas sp. MXB8 and the consortium of C. orthopsilosis MXL20 and A. niger MXPE6 can increase their dry biomass by 147% and 126%, respectively, in the presence of PCB. In the bioleaching of metals, the inoculation of A. niger MXPE6, the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 and Sphingomonas sp. MXB8 leached 54%, 44.2% and 35.8% of Ag. The consortium of A. niger MX5 and A. niger MXPE6 showed a leaching of 0.53% of Au. A. niger MX5 leaching 2.8% Cu. Citric acid increased Cu leaching by 280% compared to treatments inoculated with microorganisms. Although further research is required, A. niger MXPE6 and the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 could be an alternative to recover Ag from PCB of mobile phones.
TL;DR: The Aspergillus niger aggregate contains 15 morphologically indistinguishable species which presence is related to ochratoxin A (OTA) and fumonisin B2 (FB2) contamination of foodstuffs and there is a need of new studies regarding the risk that these species might pose to food security.