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Applied Biochemistry and Biotechnology Sep 2021β-Glucosidases primarily catalyze removal of terminal glucosyl residues from a variety of glucoconjugates and also perform transglycosylation and reverse hydrolysis.... (Review)
Review
β-Glucosidases primarily catalyze removal of terminal glucosyl residues from a variety of glucoconjugates and also perform transglycosylation and reverse hydrolysis. These catalytic properties can be readily exploited for degradation of lignocellulosic biomass as well as for pharmaceutical, food and flavor industries. β-Glucosidases have been either isolated in the native form from the producer organism or recombinantly expressed and gaged for their biochemical properties and substrate specificities. Although almond and Aspergillus niger have been instantly recognizable sources of β-glucosidases utilized for various applications, an intricate pool of novel β-glucosidases from different sources can provide their potent replacements. Moreover, one can envisage the better efficacy of these novel candidates in biofuel and biorefinery industries facilitating efficient degradation of biomass. This article reviews properties of the novel β-glucosidases such as glucose tolerance and activation, substrate specificity, and thermostability which can be useful for their applications in lignocellulose degradation, food industry, and pharmaceutical industry in comparison with the β-glucosidases from the conventional sources. Such β-glucosidases have potential for encouraging white biotechnology.
Topics: Aspergillus niger; Biocatalysis; Biotechnology; Fungal Proteins; Plant Proteins; Prunus dulcis; beta-Glucosidase
PubMed: 33871765
DOI: 10.1007/s12010-021-03568-y -
STAR Protocols Dec 2022This protocol describes procedures for quantifying Aspergillus niger growth in both solid and liquid culture. Firstly, by comparing radial growth between mutant and...
This protocol describes procedures for quantifying Aspergillus niger growth in both solid and liquid culture. Firstly, by comparing radial growth between mutant and progenitor isolates on solid agar supplemented with sublethal stressors, susceptibility coefficients can be calculated. Secondly, analysis of macromorphological growth types in liquid culture allows full quantification of how a gene of interest affects submerged growth. By combining these assays, an extensive and quantitative dataset of how a gene of interest impacts growth in this fungus is possible. For complete details on the use and execution of this protocol, please refer to Cairns et al. (2019) and Cairns et al. (2022)..
Topics: Aspergillus niger; Agar
PubMed: 36595891
DOI: 10.1016/j.xpro.2022.101883 -
The FEBS Journal Nov 2023The filamentous fungus Aspergillus niger is well known for its high protein secretion capacity and a preferred host for homologous and heterologous protein production....
The filamentous fungus Aspergillus niger is well known for its high protein secretion capacity and a preferred host for homologous and heterologous protein production. To improve the protein production capacity of A. niger even further, a set of dedicated protein production strains was made containing up to 10 glucoamylase landing sites (GLSs) at predetermined sites in the genome. These GLSs replace genes encoding enzymes abundantly present or encoding unwanted functions. Each GLS contains the promotor and terminator region of the glucoamylase gene (glaA), one of the highest expressed genes in A. niger. Integrating multiple gene copies, often realized by random integration, is known to boost protein production yields. In our approach the GLSs allow for rapid targeted gene replacement using CRISPR/Cas9-mediated genome editing. By introducing the same or different unique DNA sequences (dubbed KORE sequences) in each GLS and designing Cas9-compatible single guide RNAs, one is able to select at which GLS integration of a target gene occurs. In this way a set of identical strains with different copy numbers of the gene of interest can be easily and rapidly made to compare protein production levels. As an illustration of its potential, we successfully used the expression platform to generate multicopy A. niger strains producing the Penicillium expansum PatE::6xHis protein catalysing the final step in patulin biosynthesis. The A. niger strain expressing 10 copies of the patE::6xHis expression cassette produced about 70 μg·mL PatE protein in the culture medium with a purity just under 90%.
Topics: Aspergillus niger; CRISPR-Cas Systems; Glucan 1,4-alpha-Glucosidase; Gene Editing
PubMed: 37335926
DOI: 10.1111/febs.16891 -
Antonie Van Leeuwenhoek Sep 2022Aspergilli are among the most abundant fungi worldwide. They degrade organic material and can be pathogens of plants and animals. Aspergilli spread by forming high...
Aspergilli are among the most abundant fungi worldwide. They degrade organic material and can be pathogens of plants and animals. Aspergilli spread by forming high numbers of conidia. Germination of these stress resistant asexual spores is characterized by a swelling and a germ tube stage. Here, we show that conidia of Aspergillus niger, Aspergillus oryzae, Aspergillus clavatus, Aspergillus nidulans and Aspergillus terreus show different swelling and germ tube formation dynamics in pure water or in water supplemented with (in)organic nutrients. Apart from inter-species heterogeneity, intra-species heterogeneity was observed within spore populations of the aspergilli except for A. terreus. Sub-populations of conidia differing in size and/or contrast showed different swelling and germ tube formation dynamics. Together, data imply that aspergilli differ in their competitive potential depending on the substrate. Moreover, results suggest that intra-species heterogeneity provides a bet hedging mechanism to optimize survival of aspergilli.
Topics: Animals; Aspergillus niger; Spores, Fungal; Water
PubMed: 35857156
DOI: 10.1007/s10482-022-01762-4 -
Journal of Hazardous Materials Feb 2022The recent work aims at the use of Pantoea conspicua (MT5) and Aspergillus niger (CRS3) to assess their bioremediation potential and growth restoration of Helianthus...
The recent work aims at the use of Pantoea conspicua (MT5) and Aspergillus niger (CRS3) to assess their bioremediation potential and growth restoration of Helianthus annuus L. under chromate (Cr) stress. The growth of the P. conspicua and A. niger was tested in Cr supplemented media. The strains can withstand up to 1200 and 900 ppm respectively in the media and effectively bio-transform it to nontoxic form. Supplemented metal's levels significantly decreased the growth attribute of H. annuus (p< 0.05). On the other hand, P. conspicua and A. niger rescued the host plant by establishing higher colonization frequency with the host roots. Moreover, MT5 bio-transformed the toxic Cr to non-toxic Cr form in the rhizosphere. It also enhanced the host plant growth by producing phytohormones and ceasing Cr uptake and accumulation. Contrarily, CRS3 tends to accumulate and bio-transform metal in their hyphae. Nonetheless, both of the microbes tend to modulate phytohormones production and strengthening antioxidant system of the host. Improvement in the antioxidant system enabled the host plant to produce higher phenolics and flavonoids, and lower peroxidase. The associated plant species also exhibited higher ROS scavenging and lower ROS accumulation. Besides, the strains were able to produce higher amounts of phytohormones, including IAA, GA, and SA. Such activities rendered them as excellent phytostimulants, that can be used as biofertilizers in chromium polluted soils.
Topics: Aspergillus niger; Biodegradation, Environmental; Chromates; Chromium; Pantoea; Soil Pollutants
PubMed: 34600376
DOI: 10.1016/j.jhazmat.2021.127314 -
Critical Reviews in Biotechnology Mar 2020Citric acid is considered one of the most valuable weak organic acids on the market and its production by biotechnological approaches is a very interesting topic.... (Review)
Review
Citric acid is considered one of the most valuable weak organic acids on the market and its production by biotechnological approaches is a very interesting topic. Despite the related scientific research, the literature still lacks a state of the art for the technological innovation change, necessary for a study of the inventions designed for real scale implementation. In this context, the present review looks to account for more than 100 worldwide patents (1929-2018), necessary for the identification of the innovative markets and the most promising fields for economic investments. This deepened study identified an increasing invention number, combined with the current worldwide citric acid export flows, with China as the leader (with an economic contribution of 75%, in 2017). In order to satisfy the requests of the market which has moved toward a circular economy, the possibility to use waste substrates represents one of the main options considered in the recent patents. The discussion highlights the sustainability improvement, achieved by the conversion from a submerged technology to a solid-state fermentation ( process). The listed results are essential for both a scientific audience and the stakeholders involved in citric acid production, in order to have a complete and updated overview of this topic.
Topics: Aspergillus niger; Biotechnology; China; Citric Acid; Fermentation; Inventions
PubMed: 31903797
DOI: 10.1080/07388551.2019.1709799 -
Current Opinion in Structural Biology Aug 2022The ubiquitous UbiX-UbiD system is associated with a wide range of microbial (de)carboxylation reactions. Recent X-ray crystallographic studies have contributed to... (Review)
Review
The ubiquitous UbiX-UbiD system is associated with a wide range of microbial (de)carboxylation reactions. Recent X-ray crystallographic studies have contributed to elucidating the enigmatic mechanism underpinning the conversion of α,β-unsaturated acids by this system. The UbiD component utilises a unique cofactor, prenylated flavin (prFMN), generated by the bespoke action of the associated UbiX flavin prenyltransferase. Structure determination of a range of UbiX/UbiD representatives has revealed a generic mode of action for both the flavin-to-prFMN metamorphosis and the (de)carboxylation. In contrast to the conserved UbiX, the UbiD superfamily is associated with a versatile substrate range. The latter is reflected in the considerable variety of UbiD quaternary structure, dynamic behaviour and active site architecture. Directed evolution of UbiD enzymes has taken advantage of this apparent malleability to generate new variants supporting in vivo hydrocarbon production. Other applications include coupling UbiD to carboxylic acid reductase to convert alkenes into α,β-unsaturated aldehydes via enzymatic CO fixation.
Topics: Aspergillus niger; Carboxy-Lyases; Decarboxylation; Flavins; Prenylation
PubMed: 35843126
DOI: 10.1016/j.sbi.2022.102432 -
Toxins Dec 2020Microbial degradation is an effective and attractive method for eliminating aflatoxin B1 (AFB1), which is severely toxic to humans and animals. In this study, RAF106...
Microbial degradation is an effective and attractive method for eliminating aflatoxin B1 (AFB1), which is severely toxic to humans and animals. In this study, RAF106 could effectively degrade AFB1 when cultivated in Sabouraud dextrose broth (SDB) with contents of AFB1 ranging from 0.1 to 4 μg/mL. Treatment with yeast extract as a nitrogen source stimulated the degradation, but treatment with NaNO and NaNO as nitrogen sources and lactose and sucrose as carbon sources suppressed the degradation. Moreover, RAF106 still degraded AFB1 at initial pH values that ranged from 4 to 10 and at cultivation temperatures that ranged from 25 to 45 °C. In addition, intracellular enzymes or proteins with excellent thermotolerance were verified as being able to degrade AFB1 into metabolites with low or no mutagenicity. Furthermore, genomic sequence analysis indicated that the fungus was considered to be safe owing to the absence of virulence genes and the gene clusters for the synthesis of mycotoxins. These results indicate that RAF106 and its intracellular enzymes or proteins have a promising potential to be applied commercially in the processing and industry of food and feed to detoxify AFB1.
Topics: Aflatoxin B1; Aspergillus niger; Proteolysis; Tandem Mass Spectrometry; Tea
PubMed: 33291337
DOI: 10.3390/toxins12120777 -
Applied and Environmental Microbiology Feb 2021Salicylic acid plays an important role in the plant immune response, and its degradation is therefore important for plant-pathogenic fungi. However, many nonpathogenic...
Salicylic acid plays an important role in the plant immune response, and its degradation is therefore important for plant-pathogenic fungi. However, many nonpathogenic microorganisms can also degrade salicylic acid. In the filamentous fungus , two salicylic acid metabolic pathways have been suggested. The first pathway converts salicylic acid to catechol by a salicylate hydroxylase (ShyA). In the second pathway, salicylic acid is 3-hydroxylated to 2,3-dihydroxybenzoic acid, followed by decarboxylation to catechol by 2,3-dihydroxybenzoate decarboxylase (DhbA). cleaves the aromatic ring of catechol catalyzed by catechol 1,2-dioxygenase (CrcA) to form ,-muconic acid. However, the identification and role of the genes and characterization of the enzymes involved in these pathways are lacking. In this study, we used transcriptome data of grown on salicylic acid to identify genes ( and ) involved in salicylic acid metabolism. Heterologous production in followed by biochemical characterization confirmed the function of ShyA and CrcA. The combination of ShyA and CrcA demonstrated that -muconic acid can be produced from salicylic acid. In addition, the roles of , , and were studied by creating deletion mutants which revealed the role of these genes in the fungal metabolism of salicylic acid. Nonrenewable petroleum sources are being depleted, and therefore, alternative sources are needed. Plant biomass is one of the most abundant renewable sources on Earth and is efficiently degraded by fungi. In order to utilize plant biomass efficiently, knowledge about the fungal metabolic pathways and the genes and enzymes involved is essential to create efficient strategies for producing valuable compounds such as ,-muconic acid. ,-Muconic acid is an important platform chemical that is used to synthesize nylon, polyethylene terephthalate (PET), polyurethane, resins, and lubricants. Currently, ,-muconic acid is mainly produced through chemical synthesis from petroleum-based chemicals. Here, we show that two enzymes from fungi can be used to produce ,-muconic acid from salicylic acid and contributes in creating alternative methods for the production of platform chemicals.
Topics: Aspergillus niger; Carboxy-Lyases; Catechol 1,2-Dioxygenase; Fungal Proteins; Mixed Function Oxygenases; Phylogeny; Salicylic Acid
PubMed: 33397706
DOI: 10.1128/AEM.02701-20 -
World Journal of Microbiology &... Dec 2022Filamentous fungus Aspergillus niger has gained significant industrial and ecological value due to its great potential in enzymatic activities. The present study reports...
Filamentous fungus Aspergillus niger has gained significant industrial and ecological value due to its great potential in enzymatic activities. The present study reports the complete genome sequence of A. niger BSC-1 which was isolated from Indian Sundarban mangrove ecosystem. The study revealed that the genome of A. niger BSC-1 was 35.1 Mbp assembled in 40 scaffolds with 49.2% GC content. A total of 10,709 genes were reported out of which 10,535 genes were predicted for encoding the proteins. BUSCO assessment showed 98.6% of genome completeness indicating high quality genome sequencing. The genome sequencing of A. niger BSC-1 revealed the presence of rodA and exgA genes for initial adhesion to surface and Ags genes for matrix formation, during biofilm growth. OrthoVenn2 analysis revealed that A.niger BSC-1 shared 9552 gene clusters with the reference strain A. niger CBS554.65. Semi-quantitative RT-PCR analysis unveiled the role of Ags1 and P-type ATPase in fungal biofilm formation and chromium (Cr) resistance, respectively. During biofilm growth the expression of Ags1 significantly (P < 0.0001; two-way ANOVA followed by Sidak's multiple comparisons test) increased with respect to planktonic culture revealing the possible involvement of Ags1 in biofilm matrix formation. Expression of P-type ATPase gene was significantly upregulated (P < 0.0001; one-way ANOVA followed by Dunnett's multiple comparisons test) with the increasing chromium concentration in the fungal culture. Besides, several other genes encoding metalloprotease, copper and zinc binding proteins, and NADH-dependent oxidoreductase were also found in the genome of A. niger BSC-1. These proteins are also involved in heavy metal tolerance and nanofabrication indicating that this filamentous fungus A. niger BSC-1 could be potentially utilized for chromium detoxification through biofilm or nanobiremediation.
Topics: Aspergillus niger; Chromium; Ecosystem; Biofilms
PubMed: 36565384
DOI: 10.1007/s11274-022-03497-w