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1.
Chunqiao Xiao Huaxiang Zhang Yujuan Fang Ruan Chi 《Applied biochemistry and biotechnology》2013,169(1):123-133
A strain WHAK1, identified as Aspergillus niger, was isolated from Yichang phosphate mines in Hubei province of China. The fungus developed a phosphate solubilization zone on modified National Botanical Research Institute’s phosphate growth (NBRIP) agar medium, supplemented with tricalcium phosphate. The fungus was applied in a repeated-batch fermentation process in order to test its effect on solubilization of rock phosphate (RP). The results showed that A. niger WHAK1 could effectively solubilize RP in NBRIP liquid medium and released soluble phosphate in the broth, which can be illustrated by the observation of scanning electron microscope, energy-dispersive X-ray microanalysis, and Fourier transform infrared spectroscopy. Acidification of the broth seemed to be the major mechanism for RP solubilization by the fungus. Indeed, multiple organic acids (mainly gluconic acid) were detected in the broth by high-performance liquid chromatography analysis. These organic acids caused a significant drop of pH and an obvious rise of titratable acidity in the broth. The fungus also exhibited high levels of tolerance against temperature, pH, salinity, and desiccation stresses, although a significant decline in the fungal growth and release of soluble phosphate was marked under increasing intensity of stress parameters. Further, the fungus was introduced into the soil supplemented with RP to analyze its effect on plant growth and phosphate uptake of wheat plants. The result revealed that inoculation of A. niger WHAK1 significantly increased the growth and phosphate uptake of wheat plants in the RP-amended soil compared to the control soil. 相似文献
2.
The objective of this work was to evaluate the preservative effectiveness of liquid crystalline systems containing retynil palmitate (RP) by the challenge test (CT) and D-value. A system was developed containing water, silicon glycol copolymer, and polyether functional siloxane with 1% RP added. The analyses were carried out by methods in the U.S. Pharmacopeia (USP 31, 2008) using the microorganisms Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. The CT showed that after 7 days, all microorganisms were eliminated except A. niger, which maintained viability for at least 28 days after inoculation. Moreover, the microorganisms E. coli, P. aeruginosa, S. aureus, C. albicans, and A. niger presented different growth behaviors, evidenced by differences among the D-values calculated. It was concluded that the CT and D-value were efficient methods for evaluation of the preservative property of these formulations. 相似文献
3.
Evaluation of a PEG/hydroxypropyl starch aqueous two‐phase system for the separation of monoclonal antibodies from cell culture supernatant 下载免费PDF全文
Qiang Wu Dong‐Qiang Lin Qi‐Lei Zhang Dong Gao Shan‐Jing Yao 《Journal of separation science》2014,37(4):447-453
In this study, an aqueous two‐phase system (ATPS) with PEG and hydroxypropyl starch (HPS) was used to separate monoclonal antibody (mAb) from Chinese hamster ovary cell culture supernatant. The phase diagram of the PEG/HPS ATPS was determined, and the effects of NaCl addition were investigated. The results showed that NaCl addition could lead to a shift of the binodal curve and that phase separation would occur at higher PEG and HPS concentrations. The effects of NaCl addition, pH, and the load of cell supernatant on the partitioning of mAb in a PEG/HPS ATPS were investigated. It was found that with 6% cell supernatant and 15% NaCl addition at pH 6.0, the yield of mAb in the upper phase was 96.7% with a purity of 96.0%. The back‐extraction of mAb with a PEG/phosphate ATPS were also studied, and the results showed that after the two‐step extraction with ATPSs the purity of mAb could reach 97.6 ± 0.5% with a yield of 86.8 ± 1.0%, which was comparable to the purification with Protein A chromatography. These results indicate that the two‐step extraction with PEG/HPS and PEG/phosphate ATPSs might be a promising alternative for the separation of mAb from cell culture supernatant. 相似文献
4.
B. Szajáni Aranka Molnár Gabriella Klámar M. Kálmán 《Applied biochemistry and biotechnology》1987,14(1):37-47
A simple, one-step process, using 0.25Mp-benzoquinone dissolved in 20% dioxane at 50°C for 24 h was applied to the activation of polyacrylamide beads. The activated
beads were reacted with glucose oxidase isolated fromAspergillus niger. The coupling reaction was performed in 0.1M potassium phosphate at pH 8.5 and 0–4°C for 24 h. The protein concentration was
50 mg/mL. In such conditions, the highest activity achieved was about 100 U/g solid. The optimum pH for the catalytic activity
was shifted by about 1 pH unit in the acidic direction to pH 5.5. Between 35 and 50°C, the activity of the immobilized form
depends on the temperature to a smaller extent than that of the soluble form. Above 50°C, the activity of immobilized glucose
oxidase shows a sharper heat dependence. The enzyme-substrate interaction was not profoundly altered by the immobilization
of the enzyme. The heat resistance of the immobilized enzyme was enhanced. The immobilized glucose oxidase is most stable
at pH 5.5. The practical use of the immobilized glucose oxidase was tested in preliminary experiments for determination of
the glucose concentration in blood sera. 相似文献
5.
L. A. Harrison J. B. Parry J. M. Lynch J. H. Slater 《Applied biochemistry and biotechnology》1984,9(4):361-362
A microbial community capable of degrading pure cellulose has been isolated from soil using a continuous flow chemostat. The
component organisms have been identified as Penicillium nigricans, Paecilomyces liliacinus, Fusarium oxysporum (3 strains),
Aspergillus fumigatus, Gliocladium roseum, and Penicillium simplicissimum.
Extracellular enzyme production (exoglucanase, endoglucanase, and (Β-glucosidase) and cellulose breakdown by the whole community
and the component organisms in pure culture was measured during growth on pure cellulose in batch culture.
After 30 d, 50–60% degradation was achieved by Penicillium simplicissimum, Aspergillus fumigatus, and the mixed culture. These
cultures also produced the highest levels of extracellular endo- and exoglucanase and were able to produce the full enzyme
complex necessary for the degradation of crystalline cellulose. The other isolates were capable of 0–20% degradation and produced
lower levels of enzyme activity. Most were unable to produce the full enzyme complex.
The results indicated that the whole community was no better at degrading pure cellulose than two members in pure culture.
Since the full potential of the community may not be expressed on pure cellulose, breakdown and enzyme production was investigated
during growth on lignocellulose. A large proportion of lignocellulosic material consists of xylan and enzymes capable of degrading
this component were investigated.
The highest percentage degradation and enzyme production (with the exception of Β-glucosidase) after 15 d growth on straw
was achieved by the same three cultures. Studies of their growth on hay and straw were extended over a 60-d period. The rate
and extent of degradation of hay by P. simplicissimum and A. fumigatus was similar to that of the mixed culture, more than
40% degradation occurring in 40 d. However, differences in levels of enzyme activity were observed. The mixed culture produced
lower levels of enzyme activity (with the exception of Β-glucosidase) particularly during the initial states of degradation.
Differences in enzyme production by A. fumigatus and P. simplicissimum were also observed. A. fumigatus produced high levels
of xylanase and endoglucanase while P. simplicissimum produced high levels of exoglucanase. Similar results were observed
on straw.
The composition of the lignocellulosic material was measured by sequential chemical extraction of the solubles, hemicellulose,
cellulose, and lignin. Changes in the composition during degradation were investigated. During the growth of all three cultures
on hay, the total percentage of hemicellulose and cellulose decreased from 84% to less than 45% in 40 d.
Despite significant differences in the enzyme activity, P. simplicissimum, A. fumigatus and the mixed culture were capable
of degrading lignocellulosic material at the same rate. The production of a full cellulase complex appears to be more important
than the production of high levels of individual enzymes. 相似文献
6.
A3钢在缓蚀颜料提取液中的EIS研究 总被引:1,自引:0,他引:1
应用EIS研究了A3钢在不同 pH值的磷酸锌或三聚磷酸铝 3.5 %NaCl提取液中的腐蚀行为 .结果显示 ,相同条件下 ,A3钢的电阻值随溶液 pH值增加而增加 ,电容值则相反 .在磷酸锌3.5 %NaCl提取液中 ,因磷酸锌的溶解度太小 ,没有足够的量对金属基底A3钢进行有效的保护 .在 pH值为 6的三聚磷酸铝 3.5 %NaCl提取液中 ,A3钢表现出较明显的缓蚀现象 ,可能是因为三聚磷酸根离子与腐蚀产物Fe2 + 、Fe3+ 络合并在钢表面形成了一层致密的保护膜 ,从而有效地阻止了腐蚀介质的进一步入侵 .防蚀颜料的溶解度大小是决定它的缓蚀性能优劣的重要因素之一 相似文献
7.
《Journal of Saudi Chemical Society》2021,25(12):101395
The kinetic model of the hydrolysis of lactose by β-galactosidase from Aspergillus niger immobilized on a commercial ceramic monoliths was estimated in the attendance of lactose and its hydrolysis reaction products galactose and glucose. The aim of this work was to developing kinetic model of lactase hydrolysis by Aspergillus niger. The variables in this study are temperature, pH, enzyme concentration, substrate concentration and final product. The optimum temperature used to achieve the best hydrolysis performance in the kinetic model selection was 55 and 60 °C. The optimum pH used for enzyme activity was about 3.5 to 4. Five kinetic models were proposed to confirm experimental data the enzymatic reaction of the lactose hydrolysis by the β-galactosidase. The kinetics of lactose hydrolysis by both Immobilized and soluble lactases were scrutinized in a batch reactor system in the lack of any mass conduction restriction. In both instance the galactose inhibition kinetic models predicted the experimental data. The model is capable to fit the experimental data correctly in the extensive experimental span studied. 相似文献
8.
Application of central composite design to the optimisation of aqueous two-phase extraction of human antibodies 总被引:1,自引:0,他引:1
The partition of human antibodies in aqueous two-phase systems (ATPSs) of polyethylene glycol (PEG) and phosphate was systematically studied using first pure proteins systems and then an artificial mixture of proteins containing 1mg/ml human immunoglobulin G (IgG), 10mg/ml serum albumin and 2mg/ml myoglobin. Preliminary results obtained using pure proteins systems indicated that the PEG molecular weight and concentration, the pH value and the salts concentration had a pronounced effect on the partitioning behaviour of all proteins. For high ionic strengths and pH values higher than the isoelectric point (pI) of the contaminant proteins, IgG could be selectively recovered on the top phase. According to these results, a face centred composite design was performed in order to optimise the purification of IgG from the mixture of proteins. The optimal conditions for the isolation of IgG were observed for high concentrations of NaCl and low concentrations of both phase forming components. The best purification was achieved using an ATPS containing 8% (w/w) PEG 3350, 10% (w/w) phosphate pH 6 and 15% (w/w) NaCl. A recovery yield of 101+/-7%, a purity of 99+/-0% and a yield of native IgG of 97+/-4% were obtained. Back extraction studies of IgG to a new phosphate phase were performed and higher yields were obtained using 10% phosphate buffer at pH 6. The total extraction yield was 76% and the purity 100%. 相似文献
9.
A new extracellular ribonuclease (RNase) from a mutant of Aspergillus niger, named A. niger SA-13-20 RNase, was purified to homogeneity by (NH4)2SO4 fractionation (50-85%), DEAE-cellulose anion-exchange chromatography, ultrafiltration and Sephacryl HR-200 chromatography. The enzyme was purified up to 54.4-fold with a final yield of 24.5%. There were differences in the molecular weight, pI value and some physico-chemical properties between A. niger SA-13-20 RNase and that from the parent strain. The enzyme is monomeric and its molecular weight and isoelectric point were 40.1 kDa and 5.3, respectively. The N-terminal amino acid sequence of A. niger SA-13-20 RNase was TIDTYSSDSP. The optimum pH, temperature and buffer concentration for the enzymatic reaction were 3.5, 65 degrees C, and 0.175 M, respectively. Metal ions, such as K+, NH4+, Mg2+, and Ca2+ at the concentration of 1.0 mM had a slight activation effect on the enzyme activity and (NH4)2SO4 activated the enzyme significantly. The enzyme was stable at pH lower than 8.5 and was easy to inactivate in strong alkali solution. 相似文献
10.
Pietka-Ottlik M Wójtowicz-Młochowska H Kołodziejczyk K Piasecki E Młochowski J 《Chemical & pharmaceutical bulletin》2008,56(10):1423-1427
Different N-substituted benzisoselenazol-3(2H)-ones, analogues of ebselen were designed as new antiviral and antimicrobial agents. We report their synthesis, chemical properties as well as study on biological activity against broad spectrum of pathogenic microorganisms (Staphylococcus aureus, Staphylococcus simulans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, Aspergillus niger) and viruses (herpes simplex virus type 1 (HSV-1), encephalomyocarditis virus (EMCV), vesicular stomatitis virus (VSV)), in vitro. Most of them exhibited high activity against viruses (HSV-1, EMCV) and gram-positive bacteria strains (S. aureus, S. simulans), while their activity against gram-negative bacteria strains (E. coli, P. aeruginosa, K. pneumoniae) was substantially lower. Some of tested compounds were active against yeast C. albicans and filamentous fungus A. niger. 相似文献
11.
Isolation of Phosphate-Solubilizing Fungi from Phosphate Mines and Their Effect on Wheat Seedling Growth 总被引:1,自引:0,他引:1
Chunqiao Xiao Ruan Chi Huan He Guanzhou Qiu Dianzuo Wang Wenxue Zhang 《Applied biochemistry and biotechnology》2009,159(2):330-342
Three phosphate-solubilizing fungi, identified as Penicillium expansum, Mucor ramosissimus, and Candida krissii, were isolated from phosphate mines (Hubei, People’s Republic of China) and characterized. All the isolates demonstrated
diverse levels of phosphate-solubilizing capability in National Botanical Research Institute’s phosphate growth medium containing
rock phosphate as sole phosphate source. Acidification of culture medium seemed to be the main mechanism for rock phosphate
solubilization. Indeed, citric acid, oxalic acid, and gluconic acid were shown to be present in the culture medium inoculated
with these isolates. Moreover, the isolates produced acid and alkaline phosphatases in culture medium, which may also be helpful
for RP solubilization. A strong negative correlation between content of soluble phosphorus and pH (r = – 0.89; p < 0.01) in culture medium was observed in this study. All the isolates promoted growth, soil available phosphorus, phosphorus,
and nitrogen uptake of wheat seedling in field soil containing rock phosphate under pot culture conditions, thus demonstrating
the capability of these isolates to convert insoluble form of phosphorus into plant available form from rock phosphate, and
therefore hold great potential for development as biofertilizers to enhance soil fertility and promote plant growth. 相似文献
12.
Jianqiang Zhang Jijiang Ge Anzhou Feng Ping Jiang Ruidong Li 《Journal of Dispersion Science and Technology》2013,34(11):1589-1595
To solve the problem of high pressure of water injection in low permeability reservoirs, a high concentration of surfactant system was developed in this article. With the solubilization of oil in aqueous surfactant solution as a criterion, a formula was screened from anionic and nonionic-anionic surfactants, and the optimal depressurized system was obtained as follows, 13.3% surfactant HEX +2.23% n-propanol +4.47% n-butanol, the solubilization capability being up to 0.66 g/g. This system had good salt tolerance, and it exhibited water external microemulsion in the range of of 1 to 200 g/L NaCl. Core flooding results show that this high concentration of surfactant system formed water external microemulsion with the residual oil in the core, reducing the displacement pressure over 35%. Meanwhile, the effects of concentration and injection volume on depressurization were also investigated. It is indicated that a good depressurization effect was achieved after injecting 1 pore volume of the system with the salt concentration of 100 g/L. 相似文献
13.
O. I. Medvedeva S. S. Kambulova N. A. Ulakhovich V. V. Vorobev V. G. Evtyugin E. V. Khaldeeva M. P. Kutyreva 《Russian Journal of General Chemistry》2017,87(9):1985-1994
New composite copper nanoparticles stabilized by hyperbranched polyesterpolyols of the second, third, and forth generations have been prepared via chemical reduction at different molar ratios of the precursors. The prepared stabilized copper nanoparticles have exhibited fungicide activity against Penicillium funiculosum, Penicillium ochro chloron, Paecilomyces variotii, Aspergillus niger, Aspergillus oryzae, and Aspergillus terreus strains. Copper nanoparticles stabilized by hyperbranched polyesterpolyols of the second and forth generations are hemocompatible. 相似文献
14.
The aim of this work was to establish optimal conditions for the maximum production of endo-β-1,4 mannanases using cheaper
sources. Eight thermotolerant fungal strains were isolated from garden soil and compost samples collected in and around the
Gulbarga University campus, India. Two strains were selected based on their ability to produce considerable endo-β-1,4 mannanases
activity while growing in liquid medium at 37 °C with locust bean gum (LBG) as the only carbon source. They were identified
as Aspergillus niger gr and Aspergillus flavus gr. The experiment to evaluate the effect of different carbon sources, nitrogen sources, temperatures and initial pH of the
medium on maximal enzyme production was studied. Enzyme productivity was influenced by the type of polysaccharide used as
the carbon source. Copra meal defatted with n-hexane showed to be a better substrate than LBG and guar gum for endo-β-1,4 mannanases production by A. niger gr (40.011 U/ml), but for A. flavus gr (33.532 U/ml), the difference was not significant. Endo-β-1,4 mannanases produced from A. niger gr and A. flavus gr have high optimum temperature (65 and 60 °C) and good thermostability in the absence of any stabilizers (maintaining 50%
of residual activity for 8 and 6 h, respectively, at 60 °C) and are stable over in a wide pH range. These new strains offer
an attractive alternative source of enzymes for the food and feed processing industries. 相似文献
15.
Nikolay Vassilev Almudena Medina Bettina Eichler-Löbermann Elena Flor-Peregrín Maria Vassileva 《Applied biochemistry and biotechnology》2012,168(5):1311-1318
Cells of Aspergillus terreus, free and immobilized in polyurethane foam, were employed in itaconic acid fermentation processes on glycerol-based media. The purpose was to assess their suitability for animal bone char solubilization and the development of a biotechnological alternative to P fertilizers chemically produced from rock phosphate. Animal bones constitute a renewable source of P that can replace the traditionally used finite, nonrenewable rock phosphate as a P source. Glycerol was an excellent substrate for growth (10.2 g biomass L?1) and itaconic acid production (26.9 g?L?1) by free fungal cells after 120-h fermentation. Simultaneously, A. terreus solubilized the insoluble phosphate to a yield of 23 to 50 %, depending on the particle size and concentration. Polyurethane foam cut into cubes of 0.5–0.6 cm per side, with 0.3 mm pore size and applied at 2.0 g?L?1 proved to be an excellent cell carrier. In repeated batch fermentation, the immobilized mycelium showed a high capacity to solubilize animal bone char, which resulted on average in 168.8 mg?L–1 soluble phosphate per 48-h cycle and 59.4 % yield (percent of total phosphate) registered in the fourth batch. 相似文献
16.
Manwar AV Khandelwal SR Chaudhari BL Meyer JM Chincholkar SB 《Applied biochemistry and biotechnology》2004,118(1-3):243-251
A marine isolate of fluorescent Pseudomonas sp. having the ability to produce the pyoverdine type of siderophores under low iron stress (up to 10 μM iron in the succinate medium) was identified as Pseudomonas aeruginosa by using BIOLOG Breathprint and siderotyping. Pyoverdine production was optimum at 0.2% (w/v) succinate, pH 6.0, in an iron-deficient
medium. Studies carried out in vitro revealed that purified siderophores and Pseudomonas culture have good antifungal activity against the plant deleterious fungi, namely, Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Fusarium oxysporum, and Sclerotium rolfsii. Siderophore-based maximum inhibition was observed against A. niger. These in vitro antagonistic actions of marine Pseudomonas against phytopathogens suggest the potential of the organism to serve as a biocontrol agent. 相似文献
17.
《Journal of heterocyclic chemistry》2017,54(4):2307-2312
A practical, two‐step synthesis of crown ether functionalized pyrimidines has been developed. The reaction conditions have been optimized, and the protocol is generalized for series of substrates. These newly synthesized compounds exhibited antimicrobial activity against bacterial strains Staphylcoccus aureus (Gram‐positive) and Escherichia coli (Gram‐negative). These compounds were also found to be potent antifungal agents Aspergillus niger and Candida albicans strains, respectively. 相似文献
18.
In an attempt to obtain suitable bacterial isolates for bioleaching of copper from chalcopyrite and covellite, soil samples
taken from areas of the metal industry were screened using an enrichment procedure specially run at acidic pH and thermophilic
temperature range, to overcome the limitations of mesophiles employed for the purpose besides having economic and environmental
advantages. Of a total of 47 isolates, the most promising 3 having resistance to copper toxicity were evolved by subjecting
them to gradually increasing concentrations of CuSO4 by acclimatization runs conducted on an environmental shaker for 125 d at 65°C. The isolates, JVCu-8, JVCu-10, and JVCu-12,
exhibited significantly enhanced bioleaching and copper tolerance ability at pH 3.5 and 60–70°C. The total solubilization
of copper recorded was 87, 89.4, and 91.2% by JVCu-8, JVCu-10, and JVCu-12, respectively, and these isolates exhibited tolerance
to CuSO4 concentrations of 6.9, 7.2, and 7.2%, respectively. The isolates morphologically resembled Thiobacillus and Sulfolobus. 相似文献
19.
Costa Silgia A. Pessoa Adalberto Roberto Inês C. 《Applied biochemistry and biotechnology》1998,(1):629-639
The partitioning of xylanase produced byPenicillium janthinellum in aqueous two-phase systems (ATPS) using poly(ethylene glycol) (PEG) and phosphate (K2HPO4/KH2PO4) was studied employing a statistical experimental design. The aim was to identify the key factors governing xylanase partitioning.
The interactions of five factors (PEG concentration molecular weight, concentration of buffer K2HPO4/KH2PO4, pH, and NaCl concentration) and their main effects on the partition coefficient (K) were evaluated by means of a 25 full-factorial experimental design with four center points. The %PEG, %NaCl, and pH were the most important factors affecting
the response variable (K). Response surface methodology (RSM) was adopted and an empirical second-order polynomial model was
constructed on the basis of the results. The optimum partition conditions were pH 7.0, PEG = 8.83% and NaCl = 6.02%. Adequacy
of the model for predicting optimum response value was tested under these conditions. The experimental xylanase partition
coefficient (K) was 2.21, whereas its value predicted by the model was 2.33. These results indicate that the predicted model
was adequate for the process. PEG molecular weight and phosphate concentration did not affect the xylanase partition coefficient. 相似文献
20.
双水相萃取结合液相色谱法分离蛋白质 总被引:1,自引:0,他引:1
建立了PEG/( NH4)2SO4双水相体系萃取富集,结合液相色谱分离分析多种蛋白质的方法.考察了无机盐种类和浓度、PEG分子量、pH值和温度等因素对双水相形成以及对细胞色素C、肌红蛋白、牛血清白蛋白、溶菌酶、胰蛋白酶分配行为的影响.结果表明,上述5种蛋白在室温、pH 3.5~9.0范围内,可在15% PEG-4000/10% (NH4)2SO4双水相体系中得到富集,且主要集中在下相.同样条件下,血清中的高丰度蛋白在上下相均有分配,下相分配量较大.通过双水相萃取分离蛋白质及对液相色谱一定时间段的色谱峰收集,可初步实现血清中高丰度蛋白质的分离去除. 相似文献