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Enzymes derived from microbial sources have gained increasing popularity in industrial applications over the past decades. Despite the high production cost, alkaline proteases have wide applications in industries such as tanneries, food production, and detergents. In recent years, there has been a shift towards utilizing natural carbon sources for cultivating microorganisms and extracting proteases in order to reduce production costs. This study aimed to investigate the biochemical and kinetic properties of protease enzymes obtained from Aspergillus niger cultivated in a paper waste medium and compare with the enzyme produced in a basal medium. Glucose is a more favorable carbon source compared to cellulose, so paper waste was pretreated with cellulose-degrading bacteria to convert cellulose into smaller carbohydrates. After the growth of A. niger in basal and combinational media, the enzymatic properties were compared between the extracted enzymes by using casein as substrate. The results demonstrated that A. niger could produce protease enzymes in the paper waste medium similar to the basal medium with more than 5-fold cost saving. The specific activity of the enzymes isolated from the basal and paper waste media was calculated to be 184.95 ± 10.56 U ml−1 and 169.88 ± 11.05 U ml−1, respectively. Carbon sources did not affect the optimum pH and temperature of the protease enzyme, which were found to be 8 and 37 °C, respectively. This study provides valuable insights into the production of alkaline protease from A. niger using a combinational medium (paper waste pretreated by cellulose-degrading bacteria), offering a cost-effective approach for industrial applications. [ABSTRACT FROM AUTHOR]

Cellulase has by vast applications in the biofuel, pulp and paper, detergent and textile industries. The three components of the enzyme complex (endoglucanase, exoglucanase and β-glucosidase) can effectively depolymerize the cellulose chains in lignocellulosic substrate. Solid-state fermentation (SSF) by fungi is a preferable production route for cellulase because of its low cost, among other advantages. This work describes the cellulase production by Aspergillus niger NRRL3 grown on SSF. SSF was carried out on soybean hulls and waste paper as supports. The effect of the support on cellulase production was assessed under a completely randomized factorial design. The support-time interaction was significant for all the variables studied. Both materials were characterized in terms of water absorption index and critical humidity point. Samples of culture were analyzed with scanning electron microscopy (SEM) to study spores and fungal growth. Maximum endoglucanase activity was found at 96 h using soybean hulls as support (5914.29 U L −1 ), being four times higher than that obtained using waste paper at the same fermentation time. The exoglucanase activity in soybean hulls was maximal at 96 h (4551.19 U L −1 ), being 9.6 times higher than that obtained in waste paper at the same time. The maximum β-glucosidase activity in soybean hulls (984.01 U L −1 ) was reached at 96 h, being 1.7 times greater than that obtained in waste paper. Besides, the use of soybean hulls provided high volumetric productivities at shorter times, which may decrease production costs considering a scaled process. [ABSTRACT FROM AUTHOR]

The deinking in the paper industry is in great demand, and microbial enzymes are key players. In the present study, the endoglucanase production from newly isolated fungi Aspergillus niger MPS25 is reported. The optimization of endoglucanase production was carried out using one factor at a time approach resulting in endoglucanase activity (2.37 IU/ml) at 45 °C and pH 8 in submerged fermentation (SmF), which shows optimum enzyme activity at 60 °C. Interestingly, the metal ions viz. Co2+ stimulated the endoglucanase activity, whereas Mn2+ reduced the enzyme activity, which shows that this enzyme can be used for effluent treatment released through deinking. The enzymatic hydrolysis of wheat straw produced 26.96 ± 0.108 mg/g of reducing sugars, indicating its potential in saccharification and the biofuel industry. Furthermore, the validation of the deinking efficiency of this enzyme resulted in improved deinking of mixed office waste and old newspapers by 31.5% and 20.4%, respectively. The strength properties, viz. burst factor and tear index, breaking length, and tensile index of the handmade paper sheets, were also improved which were analyzed by the scanning electron micrographs. The FTIR and XRD analysis of pulp provided insights into the changes in functional groups and cellulose crystallinity, respectively. These results indicate that multi-efficient endoglucanase from Aspergillus niger MPS25 is suitable for enzyme-based eco-friendly deinking for waste paper recycling and lignocellulosic biomass saccharification. [Display omitted] • The endoglucanase from newly isolated fungi Aspergillus niger MPS25 is reported. • The endoglucanase showed stability at 60 °C with wide pH range. • The endoglucanase significantly improved the deinking efficiency for mixed office waste (31.5%) and old newspapers (20.4%). • The SEM, FTIR and XRD analysis provided technological insights for process scale up. • This multi-efficient endoglucanase proved to be suitable enzyme in eco-friendly recycling of MOW and ONP. [ABSTRACT FROM AUTHOR]

Abstract: Gluconic acid production was investigated using an enzymatic hydrolysate of waste office automation paper in a culture of Aspergillus niger. In repeated batch cultures using flasks, saccharified solution medium (SM) did not show any inhibitory effects on gluconic acid production compared to glucose medium (GM). The average gluconic acid yields were 92% (SM) and 80% (GM). In repeated batch cultures using SM in a turbine blade reactor (TBR), the gluconic acid yields were 60% (SM) and 67% (GM) with 80–100g/l of gluconic acid. When pure oxygen was supplied the production rate increased to four times higher than when supplying air. Remarkable differences in the morphology of A. niger and dry cell weight between SM and GM were observed. The difference in morphology may have caused a reduction of oxygen transfer, resulting in a decrease in gluconic acid production rate in SM. [Copyright &y& Elsevier]

• Density of a paper has a decisive impact on its air permeability. • Exposure of both historical and common papers to A. niger decreases permeability. • Nano-wollastonite is recommended to improve biological resistance of paper. The effect of nano-wollastonite and Aspergillus niger fungus on permeability of historical and common paper was studied here. Specimens were immersed in aqueous wollastonite nano-suspension (NW) at 10, 20, 30, and 40% concentration, and their permeability was finally compared with that obtained from control specimens. Permeability of each specimen was measured before and after the immersion in NW. To fix solid particles on NW-treated specimens, polyvinyl acetate (PVA) was mixed in all treatments. Results showed that wollastonite significantly limited the growth of A. niger. Permeability of historical specimens was significantly lower than that of the common paper, 29 in comparison to 190 cm3.s−1, respectively. This was due to the higher density in the historical paper, providing lower empty voids and spaces for fluid to pass through. Fungi culture resulted in significant decrease in both paper types. In fact, fungal hyphae penetrated into the specimens, eventually blocking the paths through which fluid could transfer. High significant R-square values were found between permeability values before and after the exposure to A. niger. It was concluded that permeability is closely correlated to the density of paper, and it has a significant effect on the potentiality of fungi hyphae to be penetrated into the texture of papers, affecting the weight loss values. Moreover, NW-suspension can be used to decrease permeability as well as susceptibility to fungal attack. [ABSTRACT FROM AUTHOR]

• Waste paper was used to obtain nanocrystalline cellulose (CNC). • The obtained CNC was compared with CNC from cotton linter. • The biocidal activity of CNC added with Ag nanoparticles was assessed. • The growth of Aspergillus niger on Whatman paper is inhibited by CNC/Ag coating. • The mechanical properties of Whatman paper improve by the CNC coatings. Waste paper is an environmentally friendly source of cellulosic material. Here we propose a new treatment based on nanocrystalline cellulose (CNC) for paper preservation and consolidation. Suspensions of CNC were prepared by sulfuric acid hydrolysis using waste paper as cellulose source (CNC WP) and compared with CNC from cotton linter (CNC CL). Both CNCs were obtained with good yield, showing high crystallinity index and comparable morphology, as demonstrated by DLS-ELS, XRD, FTIR, Raman and TEM analyses. CNCs were mixed with silver nanoparticles (CNC/Ag) and their biocidal activity was tested against Escherichia coli and Bacillus subtilis , measuring the minimum inhibitory concentration. CNCs were exploited as treatments for biocidal activity and consolidation on Whatman paper. The presence of silver nanoparticles doesn't affect aesthetic appearance of the original paper and prevents the growth of Aspergillus niger fungus. Mechanical tests demonstrated that the coatings by CNC based products improve stretch and toughness of the paper support. [ABSTRACT FROM AUTHOR]

Highlights • Starch paste was the most bioreceptive adhesive. • Starch paste was the most stable adhesive to artificial ageing. • CMC and Archibond ® showed physical-chemical and aesthetic deterioration with ageing. • CMC and Archibond ® presented only scarce bioreceptivity to the tested fungi. • MC and HPC showed the best chemical stability vs bioreceptivity relationship. Abstract In paper conservation practice, adhesives are used for several purposes, such as mending tears and gaps, or paper consolidation. The criteria to choose one or another adhesive should be based on the knowledge of the properties and stability of those adhesives. However, the several different adhesives available on the market still lack enough information to help the process of a rational decision-making. In the present work, five adhesives currently used in the paper conservation field (starch paste, unsupported Archibond TM, carboxymethylcellulose, hydroxypropylcellulose and methylcellulose) were analyzed for their chemical stability and fungal bioreceptivity (the ability of a material to be colonized by fungi). Bioreceptivity of products used in conservation and restoration is a still poorly explored subject, despite its great relevance for the preservation of objects. The chemical and physical properties of the adhesives, before and after moist heat artificial ageing, were analyzed by thermogravimetry, capillary viscometry, measurement of water absorption capacity, colourimetry, and pH measurement. Fungal bioreceptivity of the adhesives was tested on two different substrates (paper and glass) against three fungal species: Aspergillus niger, Aureobasidium pullulans and Penicillium pinophilum. Along 56 days of incubation, the colonization area on the adhesives was measured through digital photo analysis. Starch paste was the most bioreceptive adhesive, but on other hand was also the most stable adhesive to artificial ageing, regarding colour alteration, degree of polymerization and pH. Carboxymethylcellulose and Archibond TM showed chemical deterioration with ageing. Nevertheless, these two adhesives presented only scarce bioreceptivity to the tested fungi. Methylcellulose and hydroxypropylcellulose showed the best relationship between higher chemical stability with artificial ageing and lower fungal bioreceptivity. [ABSTRACT FROM AUTHOR]

Unsuitable storage conditions or accidents such as floods can present a serious threat for large quantities of book making them prone to attack by harmful microorganisms. The microbiological degradation of archives and book collections can be efficiently inhibited with irradiation processing. Application of EB irradiation to book and archive collections can also be a very effective alternative to the commonly used ethylene oxide treatment, which is toxic to the human and natural environment. In this study was evaluated the influence of EB irradiation used for microbiological decontamination process on paper-based objects. Three different kinds of paper (Whatman CHR 1, office paper and newsprint paper) were treated with 0.4, 1, 2, 5, 10 and 25 kGy electron beam irradiation. Optical and mechanical properties of different sorts of paper treated with e-beam, before and after the radiation process were studied. These results, which correlated with absorbed radiation doses effective for the elimination of Aspergillus niger (A. niger) allowed to determine that EB irradiation with absorbed radiation dose of 5 kGy ensures safe decontamination of different sorts of paper-based objects. [ABSTRACT FROM AUTHOR]

The current study was designed to isolate and identify superior cellulose-degrading fungi from Egyptian soils reached with cellulosic compounds, then production of bioethanol from paper wastes using this isolate. Among 9 fungal isolates, one isolate was selected as the highest cellulases producer. This isolate was identified by morphological and genetic characteristics as Aspergillus niger MK543209. Basal mineral salt medium amended with 1% rice straw was the best medium for cellulose-degrading enzymes production under submerged fermentation (SmF). Additionally, bagasse at 30% and urea at 2% were the best carbon and nitrogen sources, respectively. In respect to the environmental conditions, the optimum temperature, pH and incubation period were 45 °C, 5.5 and 4 days, respectively. The optimized conditions were applied to produce reducing sugars from paper wastes, followed by production of bioethanol as a renewable energy. A 0.9 g/l/h of ethanol were produced as the best value. This study may be considered the initial point for production of renewable energy and protection of environment from wastes. [ABSTRACT FROM AUTHOR]

Abstract: Zinc oxide nanoparticles were prepared and used for surface treatment of oil paintings painted on paper supports. The prepared coating mixture containing 2% of ZnO nanoparticles showed excellent transparency. The effect of coating on protecting the paper support and paintings against microbial attack by Trichoderma reesei and Aspergillus niger, dirt accumulation, and UV aging was studied. Coatings containing ZnO nanoparticles enhanced the durability of linseed oil-based paintings toward UV aging regarding the change in color. Coatings containing ZnO nanoparticles improved resistance to microbial attack when subjected to inoculums containing T. reesei or A. niger fungi. In addition, coatings containing ZnO nanoparticles reduced accumulation of dirt on oil paintings when left in open air for 6 months; cleaning of paintings was quite easy compared to the non-coated paintings or those coated with the varnish without ZnO nanoparticles. [Copyright &y& Elsevier]

Abstract: A new process using aminoalkylalkoxysilanes (AAAS) was developed recently for paper and book mass deacidification. This process is entirely novel in that, besides deacidifying, it also improves the mechanical properties of paper. In the present article, the properties of inhibition of fungal growth of the treated papers are investigated. It was found that the AAAS tested acted as surface-active antifungal agents when introduced in the paper, significantly reducing the growth of Aspergillus niger and Paecilomyces variotii, two fungal species commonly found in storage areas of libraries and archives. The AAAS which seemed the most efficient in preventing the fungal development was 3-aminopropylmethyldimethoxysilane (AMDES), functionalised with a primary amine. The effect was significant in the different papers tested which demonstrated the protection against the proliferation of filamentous fungi in vitro for papers treated with AMDES. The higher concentration of AMDES inside the paper proved to be the most effective. The highest efficiency was reached for AAAS uptakes around 6%. At this concentration the sporulation of the two strains was inhibited and the development of A. niger mycelia was highly reduced. [Copyright &y& Elsevier]

Abstract: Microbial volatile organic compounds (MVOCs) emitted from the mould species Penicillium expansum, P. chrysogenum, Aspergillus versicolor, A. fumigatus, A. niger and Cladosporium cladosporoides were analyzed by means of solid phase microextraction (SPME) and GCMS. The mould species were cultivated on the synthetic agar dichloran chloramphenicol (DG 18) and on wet wall paper. The production of MVOCs was monitored over several weeks to detect changes in the emission rates between the initial stage and later periods of growth. The cultivation on the synthetic agar resulted in MVOC patterns with a wide variety of signals. In contrast, the growth on wet wall paper led to changed MVOC patterns with less signals. The emission rates were drastically reduced. Components emitted by all six fungi species on wall paper were 2-pentanol and 2-pentanone. 1-Octen-3-ol was emitted by five fungi species. 2-Pentanol was only detected in considerable amounts during the first days of growth whereas 1-octen-3-ol had a more constant emission rate over the whole period of growth. On the basis of our studies some MVOCs could be proposed as specific for single fungi on wall paper, e.g. 1,3-dimethoxybenzene for A. versicolor and 2,4-pentandione for A. fumigatus. [Copyright &y& Elsevier]

Abstract: Intense light pulse (ILP) is one of the emerging non-thermal techniques investigated as an alternative to traditional thermal treatment because it has been proven to be effective for microbial inactivation on food surfaces and food packages. The aim of this study was to evaluate the possibility of using pulsed light treatment for the effective killing of moulds on paper–polyethylene packaging material. Coupons of 20×20mm paper–polyethylene were artificially contaminated with Cladosporium herbarum, Aspergillus niger, Aspergillus repens and Aspergillus cinnamomeus than subjected to different light energetic densities (from 0.244 to 0.977J/cm2) for different durations (from 10×10−3 to 30×10−3 s). The results showed that there is a significant reduction of population along with an increase of light fluence and ILP treatment duration. The highest level of inactivation achieved in this study was about a 2.7-log reduction, which is more than enough for a normal contaminated packaging material. It is estimated that pulse light treatment could lead to an effective reduction of moulds, being also possible to obtain a sterile surface of the packaging material. Blastospores as those produced by C. herbarum are easier destroyed (z =0.795J/cm2) than fialospores as those produced by aspergilli (z =0.81–0.927J/cm2). Spore colour seems to play some role in spore resistance to light pulses: green fialospores, as those produced by A. repens, has higher z values (0.927J/cm2) than the black or brown ones as those produced by A. niger (z =0.81J/cm2), and A. cinnamomeus (z =0.875J/cm2) respectively. [Copyright &y& Elsevier]

Old newspapers (ONP) are a significant source of raw materials for recycled paper industry. To obtain bright pulp for recycling, the ink from the ONP pulp is removed by chemical deinking process which is highly polluting and expensive. Due to high xylan content in ONP, the ink particles adhering on ONP pulp surface can be removed through detachment of ink/fiber bond by action of xylanases. In the present study, cellulase-free xylanases from fungi were specifically screened for deinking of ONP pulp. Among 16 cellulase-free xylanase producing isolates, strain DX-23 (identified as Aspergillus niger ) produced maximum xylanase (48.9±0.02 U ml −1 ). The xylanase of A. niger DX-23 (50 U g −1 pulp), efficiently deinked the ONP pulp which exhibited 34.5% ISO brightness (22% higher than the untreated pulp). Improvement up to 78.8% ISO brightness in ONP pulp compared to untreated pulp was achieved after optimization of conditions for deinking by response surface methodology and subsequent mild H 2 O 2 treatment of deinked pulp. ATR-FTIR spectra, X-ray diffraction analysis and scanning electron micrographs of pulps confirmed the removal of surface ink particles from ONP pulp. The xylanase of A. niger DX-23 possessed molecular weight of 15.0 kDa, showed maximum activity at 50 °C and pH 5.0. Additives such as Mn +2 , Fe +2 , and sodium dodecyl sulfate enhanced the activity of xylanase, whereas, Zn +2 , Mg +2 , Ca +2 and Hg +2 and EDTA completely inhibited the activity. The K m and V max for the xylanase of A. niger DX-23 for hydrolysis of Birchwood xylan was found to be 2.38 mg/ml and be 230.8 µM/min/mg, respectively. [ABSTRACT FROM AUTHOR]

Industrial enzymes particularly xylanase have more demand due to its vast commercial application in paper and pulp, food, animal feed industries as well as for bioconversion of lignocellulosic waste into valuable chemical products. Xylanases are hydrolase enzyme that catalyzes the β-1,4 linkages in heteropolysaccharide xylan which ultimately yields xylose monomers Microbes mainly fungi are used to synthesize xylanase to catalyze xylan into its component sugars that are further utilized by other microorganisms for consecutive fermentation into biofuel. The current study was focused on the dual use of different agro-industrial waste matrices under submerged fermentation to synthesize xylanase using Aspergillus niger KIBGE-IB36 that also produce xylose after enzymatic pretreatment process. Among all agricultural wastes, high titer of xylanase production (3071 Umg−1) was observed when 1% wheat bran was used. The zymographic analysis revealed multiple xylanase protein bands. To pre-treat agricultural wastes partially purified enzyme was used for different intervals of time showed increasing pattern of reducing sugars. After enzymatic saccharification, agricultural wastes were analyzed for thin layer chromatography (TLC) and scanning electron microscopy (SEM) that showed xylose production and maximum change in the surface morphology of all agricultural wastes, respectively. The present study revealed the use of fungi in low cost saccharification process which successfully developed the dual use of agricultural waste to produce xylanase and xylose after enzymatic pretreatment of xylanase that have potential to be use in food and pharmaceutical industry. Xylose can also serve as the most energy-efficient source for biofuel production. Image 1 [ABSTRACT FROM AUTHOR]

• Isolation of thirty-two fungal endophytes from stem and bark of Albizia lebbeck (L.) Benth. • Screening of fungal endophytes for extracellular enzymes amylase, protease, lipase, laccase, cellulase and gelatinase. • Exploitation of crude enzymes of endophyte Aspergillus niger in bioremediation of municipal waste water, blood stain removal, biodegradation of oil, dye decolorization of methylene blue and methyl orange, saccharification of paper and baggase and extraction of silver from x-ray film. • First report on extracellular enzyme screening of Albizia lebbeck (L.) Benth endophytes. Endophytic fungi reside inside plants in a mutualistic relationship with the host and produce numerous bioactive compounds, including extracellular enzymes. A rich diversity of endophytic fungi associated with the medicinal plant Albizia lebbeck (L.) Benth was bio-prospected in the present study. Thirty-three isolates obtained from the plant were assessed for secretion of six different extracellular hydrolytic enzymes. The results showed that 38%, 9%, 69%, 16%, 38%, and 13% of the endophytic isolates could produce amylase, protease, lipase, laccase, cellulase, and gelatinase enzymes, respectively. Overall, 78% of the isolates showed positive results for one or the other enzyme. Aspergillus niger (Isolate 8) isolated from the bark proved to be most efficient in producing all the enzymes and was further exploited for various applications. The crude fungal amylase of the isolate helped in 39.08% reduction in biochemical oxidation demand (BOD) of municipal wastewater. Effective blood stain removal from the white cotton cloth was achieved when crude protease was used in combination with detergent. 13.29% biodegradation of vegetable oil was observed using fungal lipase. Dye decolorization of methylene blue (71.65%) and methyl orange (56.53%) was observed by fungal laccase. Saccharification of bagasse (83.94%) and paper (64.93%) was achieved by using fungal cellulase. Complete extraction of silver from waste X-ray films was achieved by crude gelatinase. The results obtained in the present study can further be strengthened using purified enzymes. [ABSTRACT FROM AUTHOR]

It is well known that Trichoderma reesei 's cellulase is deficient in β-glucosidase and cellobiohydrolase II, hampering the synergism of cellulase components and attenuating the cellulose-degrading capability. T. reesei was engineered to enhance its cellobiohydrolase II and cellulase production. However, it was still deficient in β-glucosidase. Therefore, the mixed culture of the recombinant T. reesei and Aspergillus niger was introduced to further improve cellulase production and the performance in enzymatic hydrolysis. It was found to produce the most robust cellulase, whose filter paper activity was 12.17 ± 1.18 FPIU/mL, cellobiohydrolase activity 53.10 ± 2.95 U/mL, endoglucanase activity 716.11 ± 41.16 U/mL, and β-glucosidase activity 1.93 ± 0.28 IU/mL. It had the highest enzymatic hydrolysis yield 89.35%, the lowest cellulase input 25.18 FPIU for 1 g glucose. It just needed 1.96 g SECS (dry material) for producing 1 g glucose. This work is profound and meaningful for lignocellulose-based biorefineries. [ABSTRACT FROM AUTHOR]

A great amount of carrots is discarded daily in the word because they do not meet the quality standards imposed by consumer market. The aim of this work was to evaluate the feasibility of using carrot discards as substrate of solid-state fermentation to produce p-fructofuranosidase by Aspergillus niger and its subsequent use to catalyze the synthesis of fructooligosaccharides (prebiotics) using carrot juice. Results indicated that carrot bagasse has adequate nutrients for the growth of A. niger, but supplementation with a source of nitrogen is required to obtain a high production of β-fructofuranosidase (90.82 U/mL). Maximum specific activity (251 U/Ing) was obtained after 3 days of fermentation at 30 °C, using an inoculum of 106 conidia/mL. β-fructofuranosidase was successfully used to synthesize fructooligosaccharides using carrot juice as substrate, raising the possibility for future development of a natural functional beverage. Tweetable abstract: A great amount of carrots is discarded daily. This paper evaluates the use of carrot bagasse to produce β-fructofuranosidase and its subsequent application in carrot juice to produce a natural beverage with prebiotics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bioleaching combined with roasting can improve V recovery from stone coal. • V leaching rate achieved 94.52% by Aspergillus niger under optimum conditions. • Mechanisms of action of roasting and bioleaching of stone coal were elucidated. • Recovering V from stone coal by Aspergillus niger is a promising green method. Vanadium is a rare metal with excellent properties. The recovery of vanadium from low-grade stone coal and vanadium-containing solid wastes using microbial leaching, has become an increasingly popular technology. In this paper, Vanadium was obtained from stone coal using Aspergillus niger as the leaching strain, and the process of vanadium bioleaching was strengthened. Compared with plasma treatment and ultrasonic pretreatment of stone coal, the leaching effect of stone coal after roasting at 900 °C was the best, and the leaching rate of vanadium was as high as 94.52 %. The vanadium bioleaching mechanism was explored by SEM-EDS, XRD, XPS and FTIR analysis. The findings indicated that Aspergillus niger has the ability to adhere to the surface of stone coal, resulting in subsequent corrosion and degradation. The roasting treatment of stone coal and bioleaching of Aspergillus niger jointly lead to the decrease of crystallinity, the increase of interplanar spacing and the decrease of stability of stone coal. Meanwhile, the valence state and binding form of vanadium changed, and V (III) was oxidized to V (IV) and V (V). The mineral structure may be distorted as a result of the distinctive peak's vibratory stretching and the influence of functional categories that include oxygen, which in turn causes the change of the coordination form of the internal metal ions, which affects the symmetry of the mineral and facilitates the dissolution of vanadium from the stone coal. Research indicates that roasting and Aspergillus niger bioleaching have a great deal of promise to increase vanadium recovery from stone coal. [ABSTRACT FROM AUTHOR]

Abstract The antimicrobial activity and biodegradability of the biopolymer film (as a coating for kraft paper) was analysed using response-surface methodology. The results of the study showed that both the coating thickness and the turmeric oil volume significantly affected these responses. From the response-surface plot, the highest value for the inhibition zone of Aspergillus niger and the lowest weight loss during the biodegradation study were due to the slow release of antimicrobial agents. This indicates that the released of antimicrobial agents occurred during the correct stipulated period of time required to inhibit the microorganisms' growth. Therefore, the results suggested that applying a biopolymer film containing turmeric oil as a kraft-paper coating can improve the paper's packaging functionality by prolonging the shelf life of foods. In addition, all the samples degraded in typical soil conditions, showing that this coating can be disposed of in landfills after use. Highlights • Natural biopolymer films could replace polyethylene coating. • The biopolymer film was a form of active packaging with presence of turmeric oil. • Response surface methods in evaluating antimicrobial activity and biodegradability. • Both factors significantly affected all the three responses studied. [ABSTRACT FROM AUTHOR]

Contamination from external hazardous materials may greatly influence the safety and efficacy of herbal medicines. This paper aimed to evaluate the levels of contamination by mycotoxins and toxigenic fungi in herbal medicines and establish a rapid method for detecting toxin-producing fungi. Herein, 62.92%, 36.25%, and 64.17% of herbal medicines were contaminated by aflatoxins (AFs), ochratoxins, and fumonisins, respectively. Aspergillus (43.77%), Fusarium (5.17%), and Cladosporium (4.46%) were the three predominant genera. Spearman's correlation results showed that Aspergillus and Fusarium were significantly and positively correlated with mycotoxin content (R > 0.5, P < 0.05). In addition, 323 fungal strains were isolated from herbal medicines, and 20 species were identified, mainly belonging to Aspergillus and Penicillium. Analysis of potential mycotoxin-producing fungi showed that Aspergillus flavus can produce AFs, and Aspergillus ochraceus and Aspergillus niger can produce ochratoxin A (OTA). Multiplex real-time polymerase chain reaction showed that A. flavus harbored AF synthesis genes (aflR), and A. ochraceus and A. niger harbored OTA synthesis genes (aoksl). With these synthesis genes, 67.07% and 37.20% of 164 herbal medicines were positive for toxigenic genes. Furthermore, an excellent correlation was found between the above gene copies and mycotoxin content (R2 = 0.99). Our results confirmed the high detection rate of mycotoxins in herbal medicines and identified pivotal AF- and OTA-producing fungi. In conclusion, this paper provided the contamination status of fungi and mycotoxins in herbal medicines and established a rapid method for detecting toxigenic fungi. [Display omitted] • Aflatoxins, ochratoxins and fumonisins were contaminated in 62.92%, 36.25% and 64.17% of samples, respectively. • Aspergillus and Fusarium were the potential toxigenic genera. • Aspergillus flavus and Aspergillus ochraceus harbored genes aflR and aoksl , respectively. • Multiplex real-time PCR was established to detect fungi producing aflatoxins and ochratoxin A. [ABSTRACT FROM AUTHOR]

Immobilization of enzymes on aminated supports using the glutaraldehyde chemistry may involve three different interactions, cationic, hydrophobic, and covalent interactions. To try to understand the impact this heterofunctionality, we study the physical adsorption of the beta-galactosidase from Aspergillus niger , on aminated supports (MANAE) and aminated supports with one (MANAE-GLU) or two molecules of glutaraldehyde (MANAE-GLU-GLU). To eliminate the chemical reactivity of the glutaraldehyde, the supports were reduced using sodium borohydride. After enzyme adsorption, the release of the enzyme from the supports using different NaCl concentrations, Triton X100, ionic detergents (SDS and CTAB), or different temperatures (4 °C to 55 °C) was studied. Using MANAE support, at 0.3 M NaCl almost all the immobilized enzyme was released. Using MANAE-GLU, 0.3 M, and 0.6 M NaCl similar results were obtained. However, incubation at 1 M or 2 M NaCl, many enzyme molecules were not released from the support. For the MANAE-GLU-GLU support, none of the tested concentrations of NaCl was sufficient to release all enzyme bound to the support. Only using high temperatures, 0.6 M NaCl, and 1 % CTAB or SDS, could the totality of the proteins be released from the support. The results shown in this paper confirm the heterofunctional character of aminated supports modified with glutaraldehyde. [ABSTRACT FROM AUTHOR]

As the critical process for quality formation of ripened Pu-erh tea (RpPT), pile-fermentation mechanism has been widely studied by using omics approach, chemical analysis, microbial distribution and their inoculated fermentation tests. Despite several reviews about chemical compositions and health benefits in RpPT and other dark teas, more comprehensive study is requisite to summarize the pile-fermentation mechanism of RpPT and application prospects of relevant microbes. This paper aims to elaborate dominant microbes, recent advances in single- and multi-omics approaches, and pathways of characteristic components during the pile-fermentation. Microbial effects are summarized and compared, which would enhance their application potential in RpPT production. At least 93 fungi and 53 bacteria have been isolated from RpPT related to the pile-fermentation. Aspergillus niger is regarded as dominant microorganism in pile-fermentation for its higher detection frequency and relative abundance. Aspergillus , Penicillium, Rasamsoni, Rhizomucor and Bacillus genera promote RpPT quality formation. The low mycotoxins contamination risk in pile-fermentation and inoculated fermentation indicates microbial application potential in RpPT production. Several microbes are confirmed to promote formation of characteristic components including theabrownins, puerins, teadenol A, gallic acid, lovastatin, gamma-aminobutyric acid and several flavonols such as quercetin. Future studies focusing on superiority and application potential of relevant microbes in RpPT production through exogenous inoculation in the pile-fermentation are guaranteed, which could improve sensory quality and health benefits of RpPT, and shorten fermentation cycle. • A. niger dominates in pile-fermentation for quality formation of ripened Pu-erh tea (RpPT). • Low mycotoxins risk is confirmed both in pile-fermentation and inoculated fermentation. • Formation mechanisms of RpPT characteristics in pile-fermentation are clarified. • Several microbes promote formation of characteristic components such as theabrownins. • Microbial exogenous inoculation show application potential in RpPT production. [ABSTRACT FROM AUTHOR]

Navel orange peel is a potential source of soluble dietary fiber. In order to make full use of this resource and improve its physiological activities, the effects of single and mixed strains fermentation modifications were compared in this study. The structural, physicochemical, and functional properties of soluble dietary fiber fermented by Trichoderma viride and/or Aspergillus niger were investigated. The results showed that mixed fermentation resulted in significantly higher activity of complex cellulase than single fermentation. On the second day, when T. viride and A. niger were inoculated at a ratio of 3:1, the activities of carboxymethyl cellulase, β -glucosidase, and filter paper lyase were 1.54, 1.61, and 1.30 times those of single fermentation. Mixed fermentation increased the yield of soluble dietary fiber from 6.63% to 15.73%. Scanning electron microscopy and Fourier transform infrared spectroscopic analyses suggested that soluble dietary fiber produced by mixed fermentation had smaller particle size, lower crystallinity, and more disrupted structure. Moreover, the functional properties of soluble dietary fiber were remarkably improved. After mixed fermentation, the glucose and cholesterol adsorption amounts, and α -amylase inhibition activity increased by 1.51, 1.63, and 1.76 times, respectively. In summary, mixed fermentation was an efficient and environmentally friendly modification method. Modified SDF can be utilized in the food processing industry, expanding the range of by-product applications. • Orange navel peel DF was modified by fermentation with single and mixed strains. • The synergistic effect of mixed strains enhanced the complex cellulase activity. • Mixed fermentation resulted in rougher surface and smaller particle size of SDF. • Mixed fermentation enhanced the glucose and cholesterol adsorption capacities of SDF. • It contributed to the comprehensive utilization of orange navel peel. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bioleaching reactions are endergonic, non-spontaneous, and reactant-favored nature. • The degree of accessibility for elements bioleaching is as follows: As > Al > In > Sr. • The optimal bioleaching conditions include a 70 °C temperature and a 29-hour duration. • Oxalic acid acts as the main lixiviant for element extraction from LCDs using A. niger. Waste liquid crystal displays (LCDs) contain significant quantities of both valuable and hazardous metal(loid)s, presenting potential environmental risks alongside valuable opportunities for resource recovery. Biohydrometallurgy holds great promise as a technology widely applicable for dissolving metals from both ores and secondary resources. While recognized for its eco-friendliness and cost-effectiveness, bioleaching faces a challenge in terms of slow kinetics, potentially affecting process efficiency and speed. This study, for the first time, presented a comparative kinetic analysis of metal's bioleaching from end-of-life LCDs by Aspergillus niger , utilizing various rate models. Kinetic evaluation revealed different rate-determining mechanisms for each metal extraction during different time periods, indicating an overall mixed control mechanism between chemical reactivity and diffusion. The reaction rate constants and relevant calculated activation energies showed that the degree of accessibility for element's bioleaching was as follows: As > Al > In > Sr. Thermodynamic variables like activation enthalpy and entropy values determined from the Arrhenius plots at varied temperatures and the results showed that the bioleaching reactions of Al, As, In, and Sr from waste LCDs were endergonic, reactant-favored, non-spontaneous with positive Gibbs free energy values. RSM was used to optimize the interactive effects of parameters that affect the element's extraction rates. The optimal bioleaching parameters were a temperature of 70 °C, and a leaching time of 29 h, which led to the highest extraction of 81.4 % Al, 69.1 % As, 60.0 % In, and 33.3 % Sr from LCD waste under solid/liquid ratio of 10 g/L and shaking speed of 160 rpm. The findings and insights presented in this paper have the potential to advance the field and provide practical guidance for environmentally friendly and economically viable recycling of LCDs. [ABSTRACT FROM AUTHOR]

Hydrolysis of astaxanthin esters to free astaxanthin by lipase in a slug-flow microchannel reactor. • A slug-flow microchannel reactor was constructed for lipase-catalyzed hydrolysis of astaxanthin esters. • The low pressure reactor was suitable for two-phase biochemical reactions. • 75.4 % of astaxanthin ester in H. pluvialis oil was converted to free astaxanthin in 200 min. • The content of free astaxanthin in H. pluvialis oil increased from 2.13 mg/L to 18.8 mg/L after hydrolysis. Natural astaxanthin is widely used as a food and cosmetics additive because of its multiple biological activities. However, astaxanthin produced by Haematococcus pluvialis is generally esterified, and its activity is far less than that of free astaxanthin. Hydrolysis of astaxanthin esters to free astaxanthin by enzymes can overcome the drawbacks of chemical saponification methods. In this paper, a slug-flow microchannel reactor was constructed and tested in enzymatic hydrolysis of astaxanthin esters. The reactor consists of a "T" slug-flow generator, a stainless-steel microchannel, two constant-flow pumps, and a temperature controller. The reactor has the advantages of simple configuration and easy scale-up, and is suitable for two-phase biochemical reactions. Using the microchannel reactor, astaxanthin esters in H. pluvialis oil were efficiently hydrolyzed to free astaxanthin by lipase from Aspergillus niger. After hydrolysis, the content of free astaxanthin in H. pluvialis oil was 18.8 mg/L, 7.83-times higher than that before hydrolysis (2.13 mg/L). The hydrolysis rate reached 75.4 %. These results indicate that the microchannel reactor can be useful for the production of free astaxanthin from its esters. [ABSTRACT FROM AUTHOR]

The bioleaching system was established by Aspergillus niger and coal fly ash, and the bioleaching effect and mechanism of rare earth elements in coal fly ash were obtained. [Display omitted] • Aspergillus niger bioleached rare earth elements (REEs) from coal fly ash (CFA). • Organic acid production improved by optimizing the percentage content of yeast powder, and peptone. • REEs leaching rates improved by optimizing the conditions: temperature, initial pH of medium, speed and cell age. • The dissolution of REEs was mediated by organic acid acidolysis. Rare earth elements (REEs) are abundant in certain mining coal, and further enriched in coal fly ash (CFA) after coal combustion. If the appropriate leaching technology is chosen, the CFA can be used as an unconventional source of REEs. In this paper, culture conditions and bioleaching process of Aspergillus niger (A. niger) were optimized, the mechanism of acid production and factors of the bioleaching process of A. niger were discussed, and the bioleaching mechanism of REEs from CFA by A. niger was expounded. The results showed that organic nitrogen sources affected the morphology and acid production capacity of A. niger , and the A. niger used in this study mainly secreted oxalic acid (4.05 mg/L). Secondly, the initial pH value, the most influential factor, further affected the bioleaching process by affecting the acid production of A. niger. Therefore, by optimizing the initial pH value to enhance the acid production capacity of A. niger and developing the best bioleaching system, the CFA can reach a leaching rate of 30.91 % for total REEs. Finally, based on the test results of organic acids and pH, combined with previous studies, we speculated the main mechanism of REES bioleaching from CFA by A. niger as proton exchange and organic ligand complexation. Microbial leaching (e.g., A. niger) integrates economic, environmental, and resource use values. [ABSTRACT FROM AUTHOR]

Abstract: The effect of different inducers on the cellulase and hemicellulase bioproduction by Aspergillus niger NRRL-567 using apple pomace as a substrate was investigated. Rapid production of different cellulase enzymes namely, FPase (filter paper cellulase), CMCase (carboxymethyl cellulase), BGL (β-glucosidase), and xylanase were observed with peak activity reaching between 48 and 72h of fermentation period. The higher FPase and BGL activities of 133.68±5.44IU/gram dry substrate (gds) and 60.09±3.43IU/gds, respectively were observed while using CuSO4 and veratryl alcohol after 48h of incubation time. The higher CMCase activity of 172.31±14.21IU/gds was obtained with lactose after 48h of incubation period. Similarly, higher xylanase activity of 1412.58±27.9IU/gds was observed with veratryl alcohol after 72h of fermentation time. This study sheds light on the rapid bioproduction of fungal cellulase and hemicellulase using low cost waste, apple pomace as substrate when supplemented with different inducers. [Copyright &y& Elsevier]

Abstract: This project was developed to fully assess the indoor air quality in archives and libraries from a fungal flora point of view. It uses classical methodologies such as traditional culture media – for the viable fungi – and modern molecular biology protocols, especially relevant to assess the non-viable fraction of the biological contaminants. Denaturing high-performance liquid chromatography (DHPLC) has emerged as an alternative to denaturing gradient gel electrophoresis (DGGE) and has already been applied to the study of a few bacterial communities. We propose the application of DHPLC to the study of fungal colonization on paper-based archive materials. This technology allows for the identification of each component of a mixture of fungi based on their genetic variation. In a highly complex mixture of microbial DNA this method can be used simply to study the population dynamics, and it also allows for sample fraction collection, which can, in many cases, be immediately sequenced, circumventing the need for cloning. Some examples of the methodological application are shown. Also applied is fragment length analysis for the study of mixed Candida samples. Both of these methods can later be applied in various fields, such as clinical and sand sample analysis. So far, the environmental analyses have been extremely useful to determine potentially pathogenic/toxinogenic fungi such as Stachybotrys sp., Aspergillus niger, Aspergillus fumigatus, and Fusarium sp. This work will hopefully lead to more accurate evaluation of environmental conditions for both human health and the preservation of documents. [Copyright &y& Elsevier]

Abstract: Solid-state fermentation (SSF) was performed to evaluate the potential of agricultural residues for the production of cellulase and hemicellulase using individual and mixed cultures of Aspergillus niger and Trichoderma reseei. The maximum filter paper (FP) cellulase activity of 13.57IU/gram dry substrate (gds), 22.89IU/gds and 24.17IU/gds and β-glucosidase activities of 21.69IU/gds, 13.58IU/gds and 24.54IU/gds were obtained with wheat bran medium at 96h incubation period with A. niger, T. reseei and mixed-cultures of A. niger and T. reseei, respectively. Mixed-culture SSF using rice straw supplemented with wheat bran in the ratio 3:2 resulted in higher FP cellulase, β-glucosidase, endoglucanase (CMCase) and xylanase activities, compared to the activities obtained using mono-cultures. Similarly, higher FP cellulase, β-glucosidase, CMCase and xylanase activities of 35.8IU/gds (96h), 33.71IU/gds (96h), 131.34IU/gds (120h) and 3106.34IU/gds (120h) were achieved in the tray fermentation using rice straw with wheat bran in the ratio of 3:2. Results of present investigation showed that higher cellulase activity and an optimal combination of cellulase and β-glucosidase can be achieved through mixed-culture SSF in trays. The approach of utilizing negative cost agricultural wastes through tray fermentation for cellulase and hemicellulase production is expected to serve the objectives of: (a) management of wastes which would otherwise cause environmental pollution problems; (b) production of hydrolytic enzymes at low cost and; (c) simple technique requiring no sophisticated instruments with practical applications. [Copyright &y& Elsevier]

The sodium super ion conductor (NASICON) structure materials have attracted extensive attention because of its open three-dimensional crystal network framework and fast sodium ion migration rate. However, the poor electronic conductivity due to the presence of phosphate groups and the consequent high cost have been a barrier to commercialization. In this work, Na 4 MnV(PO 4) 3 (NMVP) with three-dimensional porous structure is synthesized in situ using Aspergillus niger as a biological template (noted as NMVP/ANDC). The cell wall of Aspergillus niger is rich in hydroxyl groups, which can adsorb metal ions well, so that NMVP particles can be synthesized on Aspergillus niger without stacking and agglomeration. NMVP grows along Aspergillus niger mycelium has a spongy-like three-dimensional porous network structure, which helps the contact between active materials and electrolyte, reduces the migration distance of sodium ions, and improves the conductivity of active materials. Therefore, NMVP/ANDC has good rate performance and cycle stability. It can provide 109 mAh g −1 at 0.5 C and 79.6% capacity retention after 3000 cycles at 5 C. The biological template method is proposed in this paper opens up a simple way for the preparation of other three-dimensional porous network structural materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Effective and low-cost inducer is a prerequisite for efficiency improvement in cellulase production by Trichoderma reesei . In this study, spores of Aspergillus niger enriched with cellobiase were embedded in Ca-alginate microcapsules, attaining a sustained cellobiase-release system (named CRMA) which was then used to catalyze the conversion of glucose into glucose-sophorose sugar mixture via transglycosylation. Further, the process and optimal parameters of transglycosylation reaction were studied in a 5 L reactor and the sophorose concentration reached 70.55 g/L at 50 °C, pH 4.0 with CRMA loading of 200 mL after 72 h of reaction. The obtained sugar mixture was subsequently used as both carbon source and inducer in cellulase production by Trichoderma reesei under fed-batch process. The filter paper activity (FPA) reached 90.28 IU/mL at 144 h fermentation time, 1.85-fold higher than that induced by lactose. These results indicate that the newly established strategy for soluble inducer synthesis has the potential for efficiency improvement and cost reduction in cellulase production. [ABSTRACT FROM AUTHOR]

β-glucosidase (BGL), an important component in cellulase complex, plays a crucial role in cellulose hydrolysis. However, its activity in cellulase system of Trichoderma reesei , the conventional cellulase producer, is extremely low. In this study, β-glucosidase gene ( bgl ) from Aspergillus niger was cloned and achieved secreted expression in Pichia pastoris . High-level production of BGL (129 IU/mL) was achieved in a 1 m 3 fermenter by using an optimized mixed-feed strategy, in which glycerol/methanol at the ratio of 1:5 and 30 g/L corn steep powder were fed to maintain the methanol concentration of 0.7% (v/v). The obtained BGL was then used to catalyze the synthesis of sophorose, a strong inducer for cellulase production, from glucose via a transglycosylation reaction. When used the resultant glucose-sophorose mixture (GSM) containing 7.08% sophorose as both carbon source and inducer, the cellulase yield produced by Trichoderma reesei was high up to 95.23 IU/mL (filter paper activity), which was 2.1-fold of that achieved by lactose. These results indicated that the BGL is potential for application in the cost-effective and highly efficient production of Trichoderma reesei cellulase. [ABSTRACT FROM AUTHOR]

Biomass pigments were considered as prospective alternatives to conventional synthetic dyestuffs. In this paper, biocolorants were prepared from tea polyphenols (TP) and were applied in dyeing. Crude enzyme generated by Aspergillus niger was employed to convert tea polyphenols as precursor into pigments via bioconversion, and simultaneously the dyeing of fabrics was achieved in this process. This work demonstrated that pigments prepared were able to dye fabrics with admirable color fastness and meet application requirements. The bio-pigments can be obtained from low-cost reproducible natural resource, tea stalk, which is a kind of tea residual waste. Dyeing with biomass pigments based on bioconversion was presented in this research in which no environmentally hazardous additive was employed to improve dye-uptake and fixation. Therefore, this innovative dyeing technology is a cleaner production method and the dyed fabrics can be categorized as ecological textiles. [ABSTRACT FROM AUTHOR]

β-Xylosidase plays an important role in xylan degradation by relieving the end product inhibition of endo -xylanase caused by xylo -oligosaccharides. β-Xylosidase has a wide range of applications in food, feed, paper and pulp, pharmaceutical industries and in bioconversion of lignocellulosic biomass. Hence, in the present study focused on purification, biochemical characterization and partial sequencing of purified β-xylosidase from xylanolytic strain Aspergillus niger ADH-11. Acetone precipitation followed by GPC using Sephacryl S-200 yielded 20.59-fold purified β-xylosidase with 58.30% recovery. SDS-PAGE analysis of purified β-xylosidase relieved a monomeric subunit with a molecular weight 120.48 kDa. Kinetic parameters of purified β-xylosidase viz Km, Vmax, Kcat and catalytic efficiency were assessed. Purified β-xylosidase was additionally active on p -nitrophenyl-β- d -glucopyranoside substrate also. Moreover, peptide mass fingerprinting analysis support our biochemical studies and showed that the purified protein is a novel β-xylosidase with β-glucosidase activity and belongs to the bi-functional GH3 superfamily. Besides, tolerance of purified β-xylosidase towards glucose and xylose was also assessed. [ABSTRACT FROM AUTHOR]

Shikimate is a key intermediate for the synthesis of an anti-influenza drug sold under the trade name Tamiflu ® . The metabolic pathway of shikimate has been extensively explored in Escherichia coli . This paper presents a rational strategy via cumulative disruption and overexpression of rate-limiting genes in Bacillus licheniformis , which is a GRAS (Generally Recognized as Safe) strain with high potential for the production of shikimate. The enhanced production of shikimate was achieved by the deletion of shikimate kinase (AroK) and pyruvate kinase (Pyk) as well as overexpression of transketolase (Tkt), 3-deoxy- d -arabinoheptulosonate-7-phosphate (DAHP) synthase (AroA), and shikimate dehydrogenase (AroD) respectively and the amount of byproducts was reduced significantly. Furthermore, the medium was optimized by an orthogonal test, and the titer of shikimate (21.8 g/L) produced by the strain WX-02Δ aroK Δ pyk/ pHY300- aroD increased by 56.8% compared to the original medium. This work revealed a new GRAS platform for the production of shikimate. These findings also suggest that B. licheniformis has great potential for the production of aromatic compounds of the extended shikimate pathway. [ABSTRACT FROM AUTHOR]

Phosphate chemical fertilizers are extensively used to improve agricultural productivity. However, the production of these fertilizers is expensive and can cause environmental damage. Alternatively, microbial solubilization of rock phosphate (RP) is a potential strategy for obtaining biofertilizers. This paper proposes the use of a novel combined mechanical-biological approach to produce soluble phosphate by cultivation of a selected strain of Aspergillus niger using RP with particle sizes in the nanometric range. The effect of Bayóvar RP particle size on phosphate solubilization was analyzed for cultivations under submerged (SmF) and solid-state fermentation (SSF). The RP particle size played a key role in phosphate solubilization, with gains of up to 60% for SmF and 115% for SSF. The mechanical treatment of RP, combined with the biological cultivation process, resulted in an optimized solubilization of P, and it was shown that even short periods of milling could be highly effective. This proposed strategy could contribute to advances in the current bio-based economy and assist future developments in large-scale industrial production of biofertilizers. [ABSTRACT FROM AUTHOR]

Low exoglucanase and endoglucanase activities of marine Aspergillus niger cellulase decreased the hydrolyzing ability of cellulase. To increase the activity of halostable cellulase obtained from a marine A. niger , a cellulase with endoglucanase and exoglucanase activity was efficiently expressed by constructing a vector with promoter glaA . Exoglucanase and endoglucanase activities increased from 0.21 and 4.51 U/ml of the original strain to 0.89 U/ml and 15.12 U/ml of the transformant, respectively. Filter paper activity (FPA) increased by 7.1 folds from 0.63 to 4.47 U/ml. The release of glucose by hydrolysis of wheat straw with cellulase from the transformant was 1.37 folds higher than that with cellulase from the original strain under high salinity condition. Cellulase with endoglucanase and exoglucanase activities could be well expressed in marine A. niger . The cellulase from the transformant not only showed higher activity, but also retained halostability. An appreciate proportion of β-glucosidase, exoglucanase, endgolucanasein cellulase was important for hydrolyzing cellulose. [ABSTRACT FROM AUTHOR]

In this paper, a system of cell-recycle continuous fermentation for sodium gluconate (SG) production by Aspergillus niger ( A. niger ) was established. Based on initial continuous fermentation result (100.0 h) with constant feed rate, an automatic feedback strategy to regulate feed rate using on-line physiological parameters (OUR and DO) was proposed and applied successfully for the first time in the improved continuous fermentation (240.5 h). Due to less auxiliary time, highest SG production rate (31.05 ± 0.29 g L −1 h −1 ) and highest yield (0.984 ± 0.067 mol mol −1 ), overall SG production capacity (975.8 ± 5.8 g h −1 ) in 50-L fermentor of improved continuous fermentation increased more than 300.0% compared to that of batch fermentation. Improvement of mass transfer and dispersed mycelia morphology were the two major reasons responsible for the high SG production rate. This system had been successfully applied to industrial fermentation and SG production was greatly improved. [ABSTRACT FROM AUTHOR]

Presence of microorganisms in soils strongly affects mobility of metals. This fact is often excluded when mobile metal fraction in soil is studied using extraction procedures. Thus, the first objective of this paper was to evaluate strain Aspergillus niger ’s exometabolites contribution on aluminium mobilization. Fungal exudates collected in various time intervals during cultivation were analyzed and used for two-step bio-assisted extraction of alumina and gibbsite. Oxalic, citric and gluconic acids were identified in collected culture media with concentrations up to 68.4, 2.0 and 16.5 mmol L −1 , respectively. These exometabolites proved to be the most efficient agents in mobile aluminium fraction extraction with aluminium extraction efficiency reaching almost 2.2%. However, fungal cultivation is time demanding process. Therefore, the second objective was to simplify acquisition of equally efficient extracting agent by chemically mimicking composition of main organic acid components of fungal exudates. This was successfully achieved with organic acids mixture prepared according to medium composition collected on the 12th day of Aspergillus niger cultivation. This mixture extracted similar amounts of aluminium from alumina compared to culture medium. The aluminium extraction efficiency from gibbsite by organic acids mixture was lesser than 0.09% which is most likely because of more rigid mineral structure of gibbsite compared to alumina. The prepared organic acid mixture was then successfully applied for aluminium extraction from soil samples and compared to standard single step extraction techniques. This showed there is at least 2.9 times higher content of mobile aluminium fraction in soils than it was previously considered, if contribution of microbial metabolites is considered in extraction procedures. Thus, our contribution highlights the significance of fungal metabolites in aluminium extraction from environmental samples, but it also simplifies the extraction procedure inspired by bio-assisted extraction of aluminium by common soil fungus A. niger . [ABSTRACT FROM AUTHOR]

In this paper, a bio-hydrometallurgical route based on fungal activity of Aspergillus niger was evaluated for the detoxification and recovery of Cu, Li, Mn, Al, Co and Ni metals from spent lithium-ion phone mobile batteries under various conditions (one-step, two-step and spent medium bioleaching). The maximum recovery efficiency of 100% for Cu, 95% for Li, 70% for Mn, 65% for Al, 45% for Co, and 38% for Ni was obtained at a pulp density of 1% in spent medium bioleaching. The HPLC results indicated that citric acid in comparison with other detected organic acids (gluconic, oxalic and malic acid) had an important role in the effectiveness of bioleaching using A. niger . The results of FTIR, XRD and FE-SEM analysis of battery powder before and after bioleaching process confirmed that the fungal activities were quite effective. In addition, bioleaching achieved higher removal efficiency for heavy metals than the chemical leaching. This research demonstrated the great potential of bio-hydrometallurgical route to recover heavy metals from spent lithium-ion mobile phone batteries. [ABSTRACT FROM AUTHOR]

Cassava starch granules slightly hydrolyzed by α-amylase from Aspergillus niger show significantly enhanced gelling properties (Ichihara, Fukuda, Takaha, Yuguchi, & Kitamura, 2014). This paper investigates the mechanism of these enhanced gelling properties by dynamic viscoelastic analysis and small-angle X-ray scattering (SAXS). The storage modulus ( G′) of α-amylase-treated cassava starch paste was greater than that of native cassava starch paste, and the tan δ ( G″/G′) of the treated paste was almost zero at the tested angular frequency, which is much lower than for native cassava starch. The SAXS results suggest that the microscopic gel structure is composed of highly aggregated inhomogeneous nano-scale structures and diluted regions of single and helical amylose chains. Starch crystallization and growth of aggregates were faster, and the size of aggregates larger, for α-amylase-treated cassava starch than for native starch. These results further support our hypothesis that α-amylase treatment improves the elasticity of starch gel by constructing a strong filler-in-matrix type structure. [ABSTRACT FROM AUTHOR]

The decontamination of Aflatoxin B 1 (AFB 1 ) by immobilized cells of a new mutant strain, prepared on a base of HSCAS (hydrated sodium calcium aluminosilicate), was studied. Novel strains were induced by UV irradiation, from which 50 were screened according to their degradation efficacy on AFB 1, compared with the wild strain (FS-Z1). The FS-UV1 strain exhibited highest degradation efficacy, which was confirmed by 18SrDNA to be Aspergillus niger . The results indicate that both immobilized cells and this mutant strain which are incubated for 48 h at 30 °C, would considerably remediate AFB 1 in nutrient broth culture, by 95.32% and 82.43%, respectively. By the application of samples of contaminated cottonseed meal, with results of 93.46%∼96.82%, the degradation rate was also validated. The results of Ames test indicate the mutagenic activity of treated AFB 1 is greatly abated, with treated controls. The Application of LC-q-TOFMS (liquid-chromatography, quadrupole, time-of-flight mass spectrometry) deduces the structure and molecular formulas of the degradation products. In the vivo study, the damages of photomicrographic evidence are decreased in kidney and liver and the serum biochemical parameters is improved, in response to preventative treatment with immobilized cells. This is the application of HSCAS-prepared, immobilized A. niger cells to degrade AFB 1 of contaminated samples. The investigation in this paper offers a novel path for economical, time-saving biodegradation of AFB 1 in foods and feeds. [ABSTRACT FROM AUTHOR]

In this paper, approach for real-time monitoring of sodium gluconate (SG) fermentation was established for the first time by the equations which can calculate real-time key-parameters by on-line physiological data. Based on this approach, limiting factors were found out in initial fermentation F1 and then step-wise agitation increase and improved medium recipe were proposed in fermentation F2 and F3, respectively. The highest average SG production rate (16.58 ± 0.91 g L −1 h −1 ) was achieved in fermentation F3, which was 104.2% and 48.0% higher than those in fermentation F1 and F2, respectively. Meanwhile, due to shorter fermentation period (decreased from 34 h to 18.7 h), lower biomass (about 1.5 g L −1 ) and less by-product accumulation, the overall yield of 0.943 ± 0.012 (mol mol −1 ) in fermentation F3 increased more than 16.0% compared to fermentation F1. This approach had been successfully applied to industrial fermentation and greatly improved SG production. [ABSTRACT FROM AUTHOR]

Mushroom production is the biggest solid state fermentation industry in the world. Disposal and storage of spent mushroom compost (SMC) that remains after mushroom harvest poses a big economic and environmental problem. Production of industrially important hydrolytic enzymes by fungi on various agro-industrial wastes is a significant, open chapter in biotechnology. This paper proposes a novel application of SMC as substrate for cultivation of fungi in solid state fermentation (SSF) in order to obtain the enzymes cellulase, xylanase, amylase and β-glucosidase. SMC can be used as a good substrate for cultivation of Trichoderma and Aspergillus without the addition of supplementary (nutritive) elements. Starting amount of SMC was reduced by 30% due to hydrolysis by a complex of cellulolytic enzymes. Material that is left behind is a more suitable fertilizer for horticulture. One fungal isolate was pointed out as a promising producer ( Trichoderma atroviride isolate T42). It produced the greatest amount of total protein (0.204 mg mL −1 ), five isoforms of β-glucosidase and the highest level (12 isoforms) of both endocellulase (0.76 U mL −1 ) and xylanase (2.31 U mL −1 ). The capacity of T42 to produce all examined enzymes in such a high number of isoforms demonstrates successful adaptation to new substrates. [ABSTRACT FROM AUTHOR]

Solid state fermentation with pea pod waste and Aspergillus niger HN-1 resulted in filter paper cellulase (FP) and β-glucosidase (BGL) activity of 30 FPU/gds and 270 U/gds, respectively. Validation with the response surface optimized parameters (moisture content: 65%, pH 6.0, temperature: 33 °C, time: 84 h) in a solid-state tray fermentation enhanced FP and BGL activity by about 40 and 28%, respectively. Multi-component enzyme from A. niger HN-1 produced FP, BGL, endoglucanase (EG), cellobiohydrolase (CBHI), xylanase, α- l -arabinofuranosidase, β-xylosidase and xylan esterase with activities of 41.07 ± 2.11 FPU/gds, 345.69 ± 17.1, 480.3 ± 21.5, 52.1 ± 1.5, 2800.5 ± 88.4, 88.1 ± 9.3, 280.8 ± 11.4 and 3321.7 ± 14.8 U/gds, respectively. Enzyme was optimally active at temperature and pH of 55 °C and 5.0, respectively and demonstrated thermostability by retaining >95% activity for 6 h at 55 °C. SDS-PAGE showed the presence of 11 protein bands with molecular mass ranging between 20 and 200 kDa, while zymogram revealed the presence of multiple forms of EG, CBH and BGL with varying molecular mass. Hydrolysis of sweet sorghum bagasse at relatively high substrate loading (15%, w/v) with crude enzyme at 20 FPU/gds in thermostatically controlled glass reactor led to conversion of 82–91% of holocellulose to fermentable sugars in just 24 h as evident from HPLC analysis, showing promise for the reported enzyme in bioprocessing applications. [ABSTRACT FROM AUTHOR]

The objective of this paper is to report liquefaction of pretreated and sterilized sugarcane bagasse for enhancing endoglucanase production through submerged fermentation by Aspergillus niger . After initial solid state fermentation of steam pretreated bagasse solids by A. niger , fed-batch addition of the substrate to cellulase in buffer over a 12 h period, followed by 36 h reaction, resulted in a liquid slurry with a viscosity of 0.30 ± 0.07 Pa s at 30% (w/v) solids. Addition of A. niger for submerged fermentation of sterile liquefied bagasse at 23% w/v solids resulted in an enzyme titer of 2.5 IU mL −1 or about 15× higher productivity than solid-state fermentation of non-liquefied bagasse (final activity of 0.17 IU mL −1 ). Bagasse not treated by initial solid-state fermentation but liquefied with enzyme gave 2 IU mL −1 . These results show the utility of liquefied bagasse as a culture medium for enzyme production in submerged fermentations. [ABSTRACT FROM AUTHOR]

• In-package aerosolization technology associated with antimicrobials system was designed. • Aerosolized ɛ-PL and ClO 2 could inhibit postharvest black mold caused by aspergillus niger (A. niger) on apple fruit. • Aerosolized antimicrobials increased corresponding defense-related enzyme activity of apples. • Aerosolized antimicrobials produced higher phenolic levels of apples. • Aerosolized antimicrobials improved apple's shelf life and quality. The present study aimed to investigate the inhibition of in-package aerosolized aqueous antimicrobials against postharvest black mold caused by Aspergillus niger (A. niger) on apple fruit and in maintaining fruit quality. Apple fruit is susceptible to A. niger infection during storage, resulting in a significant decline in its quality. In this paper, the ability of chlorine dioxide (ClO 2), Epsilon-polylysine (ɛ-PL), hydrogen peroxide (H 2 O 2) and ozone (O 3) to prevent and control Aspergillus infection in postharvest apples was evaluated. Results indicated that the treatments of 400 mg L−1ClO 2 , 500 mg L−1 and 1000 mg L−1 ɛ-PL could effectively alleviate the severity of postharvest black mold (A. niger) of apples and inhibit mycelial growth of A. niger. In addition, 0.5 mg L−1 O 3 and 5% H 2 O 2 also inhibited the mycelial growth of A. niger in treated apples. Further studies indicated that aerosolized ClO 2 and ε-PL increased corresponding defense-related enzyme activity and produced higher phenolic levels to improve disease-resistant of apples. Moreover, aerosolized ClO 2 , ε-PL, H 2 O 2 and O 3 could be effective for maintaining quality of apple fruit during 24 days of storage at 20 °C. The present study gives a first insight into the A. niger control effect of in-package aerosolization technology associated with antimicrobials, which may be a potential method for the inhibition of A. niger on apple fruit. [Display omitted] [ABSTRACT FROM AUTHOR]

The cellulase enzyme is used for various industrial applications such as textile, paper, food and biofuel industries. Industrially, the fungal strain, Aspergillus niger , is widely used to produce cellulase enzymes. Emerging evidence has indicated the possible role of magnetic nanocomposites in enhancing cellulase production by A. niger. The cellulase/iron oxide nanocomposites are already reported to be an eco-friendly method for modulating microbial biochemical characteristics. The present study was used to assess the efficacy of cellulase/iron oxide magnetic composites (CMNPS) for the enhanced production of cellulase enzyme. The fungal strain Aspergillus niger was isolated from the soil samples by using standard techniques. The fungi were then transfected with CMNPS and further evaluated for the production of cellulase enzyme. Synthesis of the cellulase/iron oxide magnetic composites was characterized by UV, FTIR, and XRD. The produced CMNPS was used as substrate and enzyme production. The cellulase enzyme production by Aspergillus niger was analyzed by CMC (0.82 IU/ml enzyme activity) and FPA assay (0.039 IU/ml enzyme activity). CMNPS was also analyzed by CMC (0.74 IU/ml enzyme activity) and FPA assay (0.039 IU/ml enzyme activity). Reuse of CMNPS is the ultimate application and ecofriendly approach for the synthesis of cellulase enzymes. The study concludes that the cellulase/ iron oxide nanocomposites may be a useful tool for the enhanced production of cellulase enzyme from the soil fungus A. niger. [ABSTRACT FROM AUTHOR]

Abstract: Microbial transformation stands out among the many possible semi-synthetic strategies employed to increase the variety of chemical structures that can be applied in the search for novel bioactive compounds. In this paper we obtained ent-pimaradienoic acid (1, PA, ent-pimara-8(14),15-dien-19-oic acid) derivatives by fungal biotransformation using Aspergillus niger strains. To assess the ability of such compounds to inhibit vascular smooth muscle contraction, we also investigated their spasmolytic effect, along with another five PA derivatives previously obtained in our laboratory, on aortic rings isolated from male Wistar rats. The microbial transformation experiments were conducted at 30°C using submerged shaken liquid culture (120rpm) for 10days. One known compound, 7α-hydroxy ent-pimara-8(14),15-dien-19-oic acid (2), and three new derivatives, 1β-hydroxy ent-pimara-6,8(14),15-trien-19-oic acid (3), 1α,6β,14β-trihydroxy ent-pimara-7,15-dien-19-oic acid (4), and 1α,6β,7α,11α-tetrahydroxy ent-pimara-8(14),15-dien-19-oic acid (5), were isolated and identified on the basis of spectroscopic analyses and computational studies. The compounds obtained through biotransformation (2–5) did not display a significant antispasmodic activity (values ranging from 0% to 16.8% of inhibition); however the previously obtained diterpene, methyl 7α-hydroxy ent-pimara-8(14),15-dien-19-oate (8), showed to be very effective (82.5% of inhibition). In addition, our biological results highlight the importance to study the antispasmodic potential of a large number of novel diterpenes, to conduct further structure–activity relationship investigations. [Copyright &y& Elsevier]