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1.
Of 18 commercially used textile dyes, eight were degraded by the white rot fungus,Phanerochaete chrysosporium, by 40 to 73% based on decrease of colour. Both the lignin-degrading enzyme system ofP. chrysosporium and adsorption to its cell mass were involved in the degradation of the diazo dye, Reactofix Gold Yellow. Degradation was best achieved by adding the dye to the medium and then inoculating with pre-grown mycelium; inoculation with spores resulted mainly in dye adsorption.  相似文献   

2.
An arginine specific protease, Sp-protease, was purified by column chromatography from freeze-dried Spirulina platensis using a five-step process. Purified Sp-protease has a molecular weight of 80 kDa. It hydrolyzed the synthetic substrates containing arginine residue in the P1 position but did not hydrolyze synthetic substrates containing other amino acid residues, including lysine residue in the P1 position. Among the synthetic substrates tested, a substrate of plasminogen activator (Pyr-Gly-Arg-MCA) was hydrolyzed most effectively with the enzyme (Km = 5.5 × 10−6 M), and fibrin gel was solubilized via activation of intrinsic plasminogen to plasmin with the enzyme. Activity was inhibited completely with camostat mesilate (Ki = 1.1 × 10−8 M) and leupeptin (Ki = 3.9 × 10−8 M) but was not inhibited with Nα-tosyl-L-lysine chloromethyl ketone (TLCK). The optimum pH of the enzyme has a range of pH 9.0 to pH 11.0. The optimum temperature was 50°C; the enzyme was stable at 0–50°C.  相似文献   

3.
Summary The ability of Pseudomonas aeruginosa to accumulate Cd(II) ions from wastewater industries was experimentally investigated and mathematically modelled. From the potentiometric titration and non-ideal competitive analysis (NICA) model, it was found that the biomass contains three acidic sites. The values of proton binding (pK i =1.66±3.26×10−3, 1.92±1.63×10−4 and 2.16±3.79×10−4) and binding constant of cadmium metal ions (pK M1=1.99±2.45×10−3 and pK M2=1.67±4.08×10−3) on the whole surface of biomass showed that protonated functional groups and biosorption of Cd(II) ions could be attributed to a monodentate binding to one acidic site, mainly the carboxylic group. From the isothermal sorption experimental data and Langmuir model, it was also found that the value of Langmuir equilibrium (pK f) constant is 2.04±2.1×10−5 suggesting that the carboxyl group is the main active binding site. In addition, results showed that the maximum cadmium capacity (q max) and affinity of biomass towards cadmium metal ions (b) at pH 5.1 and 20 min were 96.5±0.06 mg/g and 3.40×10−3± 2.10×10−3, respectively. Finally, interfering metal ions such as Pb(II), Cu(II), Cr(III), Zn(II), Fe(II), Mn(II), Ca(II) and Mg(II) inhibited Cd(II) uptake. Comparing the biosorption of Cd(II) by various Pseudomonas isolates from contaminated environment samples (soil and sewage treatment plant) showed that maximum capacities and equilibrium times were different, indicating that there was a discrepancy in the chemical composition between biomasses of different strains.  相似文献   

4.
Biotreatment of bagasse effluent using Phanerochaete chrysosporium (white rot fungus) is investigated. This study confirmed that lignin is the major pollutant component in this effluent followed by different carbohydrates. The treatment conditions must be very proper, especially in terms of biomass culture to achieve a successful treatment. The best conditions of temperature, biomass concentration, pH and duration for biotreatment of this effluent were 35°C, 552 mg l−1, 6 and 5 to 9 days, respectively. Under these conditions, a 9 days long treatment reduced by 98.7% the original biochemical oxygen demand (of 2,780 mg l−1) and by 98.5% the dissolved chemical oxygen demand (initial 4,200 mg l−1). Moreover, fungal treatment reduced total dissolved solids from 3,950 to 575 mg l−1 and color from 560 mg l−1 PtCo to 111 mg l−1 PtCo.  相似文献   

5.
Prospects of using marine actinobacteria as probiotics in aquaculture   总被引:1,自引:0,他引:1  
In the present study, optimum culture conditions for the production of extracellular polysaccharides (EPS) in submerged culture of an edible mushroom, Laetiporus sulphureus var. miniatus and their stimulatory effects on insulinoma cell (RINm5F) proliferation and insulin secretion were investigated. The maximum mycelial growth (4.1 g l−1) and EPS production (0.6 g l−1) in submerged flask culture were achieved in a medium containing 30 g l−1 maltose, 2 g l−1 soy peptone, and 2 mM MnSO4·5H2O at an initial pH 2.0 and temperature 25°C. In the stirred-tank fermenter under optimized medium, the concentrations of mycelial biomass and EPS reached a maximum level of 8.1 and 3.9 g l−1, respectively. Interestingly, supplementation of deep sea water (DSW) into the culture medium significantly increased both mycelial biomass and EPS production by 4- and 6.7-fold at 70% (v/v) DSW medium, respectively. The EPS were proved to be glucose-rich polysaccharides and were able to increase proliferation and insulin secretary function of rat insulinoma RINm5F cells, in a dose-dependent manner. In addition, EPS also strikingly reduced the streptozotocin-induced apoptosis in RINm5F cells indicating the mode of the cytoprotective role of EPS on RINm5F cells.  相似文献   

6.
Extracellular laccase from Panus tigrinus CBS 577.79 was produced in a bubble-column reactor using glucose-containing medium supplemented with 2,5-xylidine under conditions of nitrogen sufficiency. The main laccase isoenzyme was purified to apparent homogeneity by ultra-filtration, anion-exchange chromatography and gel filtration that led to a purified enzyme with a specific activity of 317 IU (mg protein)−1 and a final yield of 66%. Laccase was found to be a monomeric protein with a molecular mass of 69.1 kDa, pI of 3.15 and 6.9% N-glycosylation of the high mannose type. Temperature and pH optima were 55°C and 3.75 (2,6-dimethoxyphenol as substrate). At 50 and 60°C, the enzyme half-lives were 281 and 25 min, respectively. The P. tigrinus laccase oxidized a wide range of both naturally occurring and synthetic aromatic compounds: the highest catalytic efficiencies were for 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic) acid and 2,6-dimethoxyphenol (5.99 × 106 and 3.07 × 106 M−1 s−1, respectively). Catalytic rate constants for typical N–OH redox mediators, such as 1-hydroxybenzotriazole (2.6 s−1), violuric acid (8.4 s−1) and 2,2,6,6-tetramethylpiperidin-N-oxide radical (7.8 s−1), were found to be higher than those reported for other high redox potential fungal laccases.  相似文献   

7.
A chemically defined medium for mycelial growth and exopolysaccharide (EPS) production by submerged culture of Phellinus igniarius was investigated. The mainly defined medium compositions were optimized by using orthogonal matrix method. The optimal defined medium (per liter) was 40.0 g glucose, 4.0 g. glutamic acid, 4.0 g (NH4)2SO4, and initial pH 6.0. Under the optimal medium, the maximal mycelial biomass and EPS production were 12.33 ± 0.89 and 1.21 ± 0.08 g l−1 at 192 h in shake flask, while the maximal mycelial biomass and EPS production reached 13.86 ± 0.52 and 1.92 ± 0.07 g l−1 at 168 h in 3 l fermenter, respectively. The molecular weights (g mol−1) of four fractions isolated from EPS by gel permeation were about 6.4 × 106, 3.3 × 105, 2.7 × 105 and 2.9 × 103. This study should be widely applied to other secondary metabolites production from higher fungus in a chemically defined medium and quantitative regulation of the metabolic flux in polysaccharide biosynthesis.  相似文献   

8.
A medicinal mushroom, Phellinus linteus, was successfully cultivated using a cheese-processing waste, whey, and the optimal bioconversion conditions for the maximum mycelial growth rate was also estimated through solid-state cultivation experiments. Response surface analysis with a face-centered design (center point replication = 5) was applied to statistically approximate the simultaneous effects of the three variables, i.e., substrate concentration (10–30 g lactose l−1), temperature (20–30°C), and pH (4–6), on the mycelial growth rate of P. linteus. The following is a partial cubic model where η is the mycelial growth rate (K r ) and x k is the corresponding variable term (k = substrate concentration, temperature, and pH in order): η = −23.8 + 8.67 × 10−2 x 1 + 1.48x 2 + 1.77x 3 + 8.00 × 10−4 x 1 x 2 + 7.25 × 10−2 x 1 x 3 + 5.13 × 10−2 x 2 x 3 −1.28 × 10−2 x 12 –3.18 × 10−2 x 22. −2.64 × 10−1 x 32 −3.28 × 10−3 x 1 x 2 x 3 + 4.68 × 10−4 x 12 x 2. The produced response surface model proved to be significant (r 2 > 0.99, P-value <0.0001, coefficient of variation <5%) to describe the explored space. Temperature was found to be the most significant factor of dominant effects on the mycelial growth rate, and other variables such as temperature2, pH, pH2, and (substrate concentration2 × temperature) also showed significant effects on the model output. The maximum mycelial growth rate was predicted to be 2.80 mm d−1 at 29.7 g lactose l−1, 26.2°C, and pH 5. Our results proved a good potential of whey to serve as an alternative growth medium for cultivating P. linteus mycelia. This may provide another potential for managing this nutrient-rich waste in a cost-effective way.  相似文献   

9.
The little studied white rot fungus Ischnoderma resinosum was tested for its ability to decolorize seven different synthetic dyes. The strain efficiently decolorized Orange G, Amaranth, Remazol Brilliant Blue R, Cu-phthalocyanin and Poly R-478 on agar plates and in liquid culture at a relatively high concentration of 2–4 and 0.5–1 g l−1, respectively. Malachite Green and Crystal Violet were decolorized to a lower extent up to the concentration of 0.1 g l−1. Decolorization capacity of I. resinosum was higher than that in Phanerochaete chrysosporium, Pleurotus ostreatus or Trametes versicolor. In contrast with these thoroughly examined fungi, I. resinosum was able to degrade a wide spectrum of chemically and structurally different synthetic dyes. I. resinosum also efficiently decolorized dye mixtures. In liquid culture, Orange G and Remazol Brilliant Blue R were decolorized most rapidly; the process was not affected by different nitrogen content in the media. Shaken cultivation strongly inhibited the decolorization of Orange G.  相似文献   

10.
Zhang SJ  Yang M  Yang QX  Zhang Y  Xin BP  Pan F 《Biotechnology letters》2003,25(17):1479-1482
Three reactive dyes were rapidly adsorbed by the mycelium pellets of Penicillium oxalicum. Dye removal of Reactive Blue 19 was up to 60% in 10 min and 91% in 80 min. Dye adsorption isotherms fitted Langmuir model well and the maximum adsorption capacities at 20 °C were calculated to be 160 mg g–1 for Reactive Blue 19, 122 mg g–1 for Reactive Red 241 and 137 mg g–1 for Reactive Yellow 145, respectively. The pellets exhibited a high dye adsorption capacity (80–180 mg g–1) for all of the 3 dyes over a wide pH range (pH 2–10), and the maximum adsorption was obtained at pH 2. The adsorption capacity was mildly increased by increasing salinity.  相似文献   

11.
Aureobasidium pullulans (de Bary) Arnaud (Ach 1-1) was grown in a glucose fed-batch fermentor to 106 g dry wt l−1 in 48 h. The cells were dried in a fluidized bed dryer with a final viability of 62%. After 7 months at 4°C, the viability was 28% of the initial value (= 2.3 × 1010 c.f.u. g−1 dry matter). A protection level of 89% was achieved with the biomass preparation at 1 × 108 c.f.u. ml−1 after 28 and 7 days for apples stored respectively at 5 and 25°C against Penicillium expansum. Our process is suitable to produce large quantities of the strain Ach 1-1 as biological control agent for apple preservation.  相似文献   

12.
In this study Aspergillus oryzae was utilized to remove azo dyes from aqueous solution. Physically induced in its paramorphogenic form to produce standardized mycelial pellets, the non-autoclaved and autoclaved hyphae biomass was applied to biosorb the reactive dyes Procion Red HE7B (PR-HE7B) and Procion Violet H3R (PV-H3R) at different pH values (2.50, 4.50, and 6.50). The best pH for biosorption was 2.50, though the autoclaved demonstrated a higher biosorption capacity than the non-autoclaved pellets. The toxicity level was determined using the Trimmed Spearman–Karber method with Daphnia similis in all bioassays. The calculated toxicity of PV-H3R (LC100 62.50 μg mL−1) was higher than to PR-HE7B (LC100 300.00 μg mL−1), and its results brought out that the decrease of toxicity levels to zero might be accomplished by adding small quantities of pelletized A. oryzae to the solutions.  相似文献   

13.
Summary Three laboratory-scale water pipe systems were set up to study the effects of adding two levels of acetic acid (10 and 50 μg acetate eq-C l−1) on the bacterial regrowth in water pipes. The results of the water pipe test showed that nearly all carbon in the acetic acid could be readily utilized by bacteria and resulted in an increase in biomass concentration. The maximum heterotrophic plate counts in biofilm were equal to 3.5 × 104, 8.9 × 105 and 2.9 × 107 c.f.u. cm−2 while the maximum heterotrophic plate counts of free bacteria were equal to 1.2 × 103, 5.0 × 103 and 6.8 × 104 c.f.u. ml−1 for the blank and with addition of 10 and 50 μg acetate eq-C l−1. These results showed that addition of acetic acid to drinking water has a positive effect on the assimilable organic carbon content of drinking water and bacterial regrowth in the distribution system. This effect is enhanced with addition of high-level acetic acid. Batch tests were also conducted using water samples collected from a Taiwanese drinking water distribution system. The bacterial regrowth potentials of the blank were equal to 4.3 × 103, 1.5 × 104, 4.9 × 104 and 7.5 × 104 c.f.u. ml−1 for water samples collected from treatment plant effluent, commercial area, mixed area, and residential area, respectively. These results showed that the biological stability of drinking water is the highest in treatment plant effluent, followed by distributed water of the commercial area, distributed water of the mixed area, and then the distributed water of residential area.  相似文献   

14.
Changes of polyol contents in the mycelium and fruit-bodies ofFlammulina velutipes were measured. The results suggested that arabinitol is accumulated in the fruit-bodies as the end-product after its translocation from the mycelium, while mannitol in the fruit-bodies is converted into fructose by the action of mannitol dehydrogenase (MDH). The development of fruit-bodies was promoted by feeding of mannitol to the mycelial colony. A14C tracer experiment indicated that half of mannitol translocated from mycelium to fruit-bodies was utilized for fruit-body development. NAD-linked MDH andd-arabinitol dehydroganase (D-ADH) were detected in both mycelium and fruit-bodies. The activities of MDH and ADH in the mycelium reached their maximum levels in the inital stage of fruit-body development and decreased thereafter. In contrast, the activity of MDH in the fruit-bodies showed a peak in the middle stage of development. The activity of ADH in the fruit-bodies was less than half of that of MDH. MDH showed a lower Km value for mannitol (1.3 ×10−3M) than for fructose (6.0×10−2 M). The Km value of ADH for arabinitol was extremely high (1.3×10−1M).  相似文献   

15.
This work was aimed at producing inulinase by solid-state fermentation of sugarcane bagasse, using factorial design to identify the effect of corn steep liquor (CSL) and soybean bran concentration, particle size of bagasse and size of inoculum. Maximum inulinase activity achieved was 250 U per g of dry substrate (gds) at 20% (w/w) of CSL, 5% (w/w) of soybean bran, 1 × 1010 cells mL−1 and particle size of bagasse in the range 9/32 mesh. The use of soybean bran decreased the time to reach maximum activity from 96 to 24 h and the maximum productivity achieved was 8.87 U gds−1 h−1. The maximum activity was obtained at pH 5.0 and 55.0°C. Within the investigated range, the enzyme extract was more thermostable at 50.0°C, showing a D-value of 123.1 h and deactivation energy of 343.9 kJ gmol−1. The extract showed highest stability from pH 4.5 to 4.8. Apparent K m and V max are 7.1 mM and 17.79 M min−1, respectively.  相似文献   

16.
The fungal strain A. niger SA1 isolated from textile wastewater pond proved to be an important source of remediation (decolorization/degradation) for textile dye, AR 151 (Reactive diazo dye) under different physicochemical conditions. Decolorization assays of AR 151 were carried out in Simulated textile effluent under shake flask condition for 8 days. Decolorization (at 20 mg l−1 of dye) and related biomass production overall decreased with increase in pH from 5 to 9, at 30°C. It was maximum (95.71%) at pH 5 with highest amount of three residual products (36.91 (α-naphthol = 5.72) (sulfanilic acid = 24.81) (aniline = 6.38)) besides 2.05 mg ml−1 of biomass production at an optimum concentration 6 and 0.1 mg l−1 of glucose and urea respectively. The formation of the three products followed a quite different pattern at different pH values, however, it was considerably low (Total = 2.81 mg l−1) compared to the amount of decolorization (67.26%) at pH 8. Decolorization (95–97%) was most favored under mesophilic temperature (25–45°C). It increased i.e., 90–98% with subsequent increase in dye from 10 to 100 mg l−1, kept ≥50% below 400 mg l−1 and drastically declined to 17% at 500 mg l−1 of dye. Apparently, decolorization is found to be associated with fungal growth and hyphal uptake mechanism (Biosorption/Bioadsorption), however, mineralization of AR 151 and related products under different operational conditions also suggested a metabolically mediated decolorization/degradation.  相似文献   

17.
Isolation and characterization of extra-(PE-1) and intra-cellular (PE-2) metal proteinases produced during the spawn-running process ofHypsizygus marmoreus were carried out. These enzymes were the most active toward Hammarsten casein at pH 7.0 (PE-1) and pH 6.5–7.5 (PE-2). The molecular weight and pl value of PE-1 were 29,500, 8.8 and those of PE-2 were 21,500, 8.4. Km values against the synthetic peptide substrate Z-Gly-l-Leu-NH2 were 0.9×10−3M (PE-1) and 1.2×10−3M (PE-2). PE-1 was strongly inhibited by phosphoramidon, whereas PE-2 was weakly inhibited. These enzymes are considered to play an important role in providing nitrogenous substrates during fruit-body formation.  相似文献   

18.
Maltose and yeast extract were the most favourable carbon and nitrogen sources for exopolysaccharide production by submerged culture of Shiraia bambusicola WZ-003, and initial maltose and yeast extract concentrations were at 30 and 3 g l−1, respectively. Plant oils could increase the mycelial growth and exopolysaccharide production in tested concentration. K+ and Mg2+ could enhance the mycelial growth and exopolysaccharide biosynthesis. The optimal cultivation temperature and initial pH were found to be 26°C and 6.0, respectively. Exopolysaccharide concentration reached 0.53 g l−1 in 15-l fermenter under optimal nutritional conditions.  相似文献   

19.
Four different β-galactosidases (previously named BbgI, BbgII, BbgIII and BbgIV) from Bifidobacterium bifidum NCIMB41171 were overexpressed in Escherichia coli, purified to homogeneity and their biochemical properties and substrate preferences comparatively analysed. BbgI was forming a hexameric protein complex of 875 kDa, whereas BbgII, BbgIII and BbgIV were dimers with native molecular masses of 178, 351 and 248 kDa, respectively. BbgII was the only enzyme that preferred acidic conditions for optimal activity (pH 5.4–5.8), whereas the other three exhibited optima in more neutral pH ranges (pH 6.4–6.8). Na+ and/or K+ ions were prerequisite for BbgI and BbgIV activity in Bis–Tris-buffered solutions, whereas Mg++ was strongly activating them in phosphate-buffered solutions. BbgII and BbgIII were slightly influenced from the presence or absence of cations, with Mg++, Mn++ and Ca++ ions exerting the most positive effect. Determination of the specificity constants (k cat/K m) clearly indicated that BbgI (6.11 × 104 s−1 M−1), BbgIII (2.36 × 104 s−1 M−1) and especially BbgIV (4.01 × 105 s−1 M−1) are highly specialised in the hydrolysis of lactose, whereas BbgII is more specific for β-d-(1→6) galactobiose (5.59 × 104 s−1 M−1) than lactose (1.48 × 103 s−1 M−1). Activity measurements towards other substrates (e.g. β-d-(1→6) galactobiose, β-d-(1→4) galactobiose, β-d-(1→4) galactosyllactose, N-acetyllactosamine, etc.) indicated that the β-galactosidases were complementary to each other by hydrolysing different substrates and thus contributing in a different way to the bacterial physiology.  相似文献   

20.
Purple Loosestrife is rapidly displacing native vegetation in North American wetlands. Associated changes in wetland plant communities are well understood. Effects of Loosestrife invasion on nutrient cycling and decomposition rates in affected wetlands are unknown, though potentially of significance to wetland function. We used litter bag methods to quantify decomposition rates and phosphorus concentrations of purple Loosestrife (Lythrum salicaria) and native cattails (Typha spp.) in fourteen Minnesota wetlands. A 170-day study that began in autumn modeled decomposition of Loosestrife leaves. Loosestrife stems andTypha shoots that had overwintered and fragmented were measured in a 280- day study that began in spring. In general, Loosestrife leaves decomposed most rapidly of the three;Typha shoots decomposed faster than Loosestrife stems. Significant decay coefficients (k-values) were determined by F-testing single exponential model regressions of different vegetation types in the fourteen wetlands. Significant decay coefficients were:k = 2.5 × 10−3 and 4.32 × 10−3 for all Loosestrife leaves (170 d);k = 7.2 × 10−4 and 1.11 × 10−3 for overwintered Loosestrife stems (280-d) andk = 7.9 × 10−4, 1.42 × 10−3 and 2.24 × 10−3 for overwinteredTypha shoots (280-d). Phosphorus concentrations of plant tissue showed an initial leaching followed by stabilization or increase probably associated with microbial growth. Loosestrife leaves had twice the phosphorus concentration of Loosestrife stems andTypha shoots. Our results indicate that conversion of wetland vegetation from cattails to Loosestrife may result in significant change in wetland function by altering timing of litter input and downstream phosphorus loads. Conversion of a riverine, flow- through wetland fromTypha to Loosestrife may effectively accelerate eutrophication of downstream water bodies. Impacts of Loosestrife invasion must be considered when wetlands are managed for wildlife or for improvement of downstream water quality.  相似文献   

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