共查询到20条相似文献,搜索用时 273 毫秒
1.
Sangeeta Yadav Pramod Kumar Yadav Dinesh Yadav Kapil Deo Singh Yadav 《Applied biochemistry and biotechnology》2009,159(1):270-283
An indigenously isolated fungal strain identified as Aspergillus terricola with assigned fungal strain number MTCC 7588 has been used as source for pectin lyase production. The extracellular pectin
lyase was purified to homogeneity from the culture filtrate of A. terricola by ion exchange and gel filtration chromatography. The determined molecular weight was 35 ± 01 kDa. The K
m and k
cat (turnover) values of the purified enzyme at 37 °C using citrus pectin as the substrate were found to be 1.0 mg/ml and 110.0 s−1, respectively. The pH and temperature optima of the enzyme were 8.0 and 50 °C, respectively. The retting ability of the purified
pectin lyase for natural fibers viz. Cannabis sativa and Linum usitatissimum has been demonstrated for the first time. 相似文献
2.
Andre Ricardo de Lima Damásio Tony Márcio da Silva Alexandre Maller Jo?o Atílio Jorge Hector Francisco Terenzi Maria de Lourdes Teixeira de Moraes Polizeli 《Applied biochemistry and biotechnology》2010,160(5):1496-1507
An extracellular polygalacturonase (PG) produced from Paecilomyces variotii was purified to homogeneity through two chromatography steps using DEAE-Fractogel and Sephadex G-100. The molecular weight
of P. variotii PG was 77,300 Da by gel filtration and SDS-PAGE. PG had isoelectric point of 4.37 and optimum pH 4.0. PG was very stable
from pH 3.0 to 6.0. The extent of hydrolysis of different pectins by the purified enzyme was decreased with an increase in
the degree of esterification. PG had no activity toward non-pectic polysaccharides. The apparent K
m and V
max values for hydrolyzing sodium polypectate were 1.84 mg/mL and 432 μmol/min/mg, respectively. PG was found to have temperature
optimum at 65 °C and was totally stable at 45 °C for 90 min. Half-life at 55 °C was 50.6 min. Almost all the examined metal
cations showed partial inhibitory effects under enzymatic activity, except for Na+1, K+1, and Co+2 (1 mM) and Cu+2 (1 and 10 mM). 相似文献
3.
Yi Wang Jian Zhao Jian-He Xu Li-Qiang Fan Su-Xia Li Li-Li Zhao Xiao-Bo Mao 《Applied biochemistry and biotechnology》2010,162(8):2387-2399
A lipase gene from Serratia marcescens ECU1010 was cloned into expression vector pET28a, sequenced, and overexpressed as an N terminus His-tag fusion protein in
Escherichia coli. Through the optimization of culture conditions in shake flask, the lipase activity was improved up to 1.09 × 105 U/l, which is a great improvement compared to our previous reports. It was purified to homogeneity by Ni-NTA affinity chromatography
with an overall yield of 59.4% and a purification factor of 2.4-fold. This recombinant lipase displayed excellent stability
below 30 °C and within the pH range of 5.0−6.8, giving temperature and pH optima at 40 °C and pH 9.0, respectively. The lipase
activity was found to increase in the presence of metal ions such as Ca2+, Cu2+, and some nonionic surfactants such as PEG series. In addition, among p-nitrophenyl esters of fatty acids with varied chain length, the recombinant lipase showed the maximum activity on p-nitrophenyl laurate (C12). Using racemic trans-3-(4′-methoxy-phenyl)-glycidyl methyl ester [(±)-MPGM] as substrate, which is a key chiral synthon for production of diltiazem,
a 50% conversion yield was achieved after 4 h in toluene–water (100 mM KPB phosphate buffer, pH 7.5) biphasic system (5:5 ml)
at 30 °C under shaking condition (160 rpm), affording (−)-MPGM in nearly 100% ee. The K
m and V
max values of the lipase for (±)-MPGM were 222 mM and 1.24 mmol min−1 mg−1, respectively. The above-mentioned features make the highly enantioselective lipase from Serratia marcescens ECU1010 a robust biocatalyst for practical use in large-scale production of diltiazem intermediate. 相似文献
4.
A phosphite dehydrogenase gene (ptdhK) consisting of 1,011-bp nucleotides which encoding a peptide of 336 amino acid residues was cloned from Pseudomonas sp. K. gene ptdhK was expressed in Escherichia coli BL21 (DE3) and the corresponding recombinant enzyme was purified by metal affinity chromatography. The recombinant protein
is a homodimer with a monomeric molecular mass of 37.2 kDa. The specific activity of PTDH-K was 3.49 U mg−1 at 25 °C. The recombinant PTDH-K exhibited maximum activity at pH 3.0 and at 40 °C and displayed high stability within a
wide range of pHs (5.0 to 10.5). PTDH-K had a high affinity to its natural substrates, with K
m values for sodium phosphite and NAD of 0.475 ± 0.073 and 0.022 ± 0.007 mM, respectively. The activity of PTDH-K was enhanced
by Na+, NH4+, Mg2+, Fe2+, Fe3+, Co2+, and EDTA, and PTDH-K exhibited different tolerance to various organic solvents. 相似文献
5.
Yihang Li Bo Zhang Xiang Chen Yiqun Chen Yunhe Cao 《Applied biochemistry and biotechnology》2010,160(5):1321-1331
The gene xynB from Aspergillus sulphureus encoding the endo-β-1,4-xylanase was de novo synthesized by splicing overlap extension polymerase chain reaction according
to Pichia pastoris protein’s codon bias. The synthetic DNA and wild-type DNA were placed under the control of a glyceraldehyde-3-phosphate dehydrogenase
gene promoter (GAP) in the constitutive expression vector plasmid pGAPzαA and electrotransformed into the P. pastoris X-33 strain, respectively. The transformants screened by Zeocin were able to constitutively secrete the xylanase in YPD liquid
medium. The maximum yield of the recombinant xylanase produced by the synthetic DNA was 105 U ml−1, which was about 5-fold higher than that by wild-type DNA under the flask culture at 28 °C for 3 days. The enzyme showed
optimal activity at 50 °C and pH 5.0. The residual activity remained above 90% after the recombinant xylanase was pretreated
in Na2HPO4–citric acid buffer (pH 2.4) for 2 h. The xylanase activity was significantly improved by Zn2+. These biochemical characteristics suggest that the recombinant xylanase has a prospective application in feed industry as
an additive. 相似文献
6.
Jong Il Lee Yun Jae Kim Heejin Bae Sung Suk Cho Jung-Hyun Lee Suk-Tae Kwon 《Applied biochemistry and biotechnology》2010,160(6):1585-1599
The Thermococcus peptonophilus (Tpe) DNA polymerase gene was expressed under the control of the T7lac promoter on pET-22b(+) in Escherichia coli BL21-CodonPlus(DE3)-RIL in order to fully elucidate its biochemical properties and evaluate its feasibility in polymerase
chain reaction (PCR) application. The expressed enzyme was then purified by heat treatment followed by two steps of column
chromatography after which optimum pH and temperature of the enzyme were evaluated to be 7.0 and 75 °C, respectively. The
optimal buffer for PCR with Tpe DNA polymerase consisted of 50 mM Tris–HCl (pH 8.0), 2 mM MgCl2, 80 mM KCl, and 0.02% Triton X-100. Tpe DNA polymerase revealed a 3.6-fold higher fidelity (3.37 × 10−6) than Taq DNA polymerase (12.13 × 10−6) and performed significantly more efficiently in PCR amplification than both Taq and Pfu DNA polymerases. Ratios of 31:1 of Taq to Tpe DNA polymerases allowed PCR amplification of targets up to 15 kb in length with a 2.2-fold higher fidelity than Taq DNA polymerase. The results of the PCR experiments indicate that Tpe DNA polymerase may provide a higher fidelity DNA amplification in a shorter reaction time. 相似文献
7.
Taibi Z Saoudi B Boudelaa M Trigui H Belghith H Gargouri A Ladjama A 《Applied biochemistry and biotechnology》2012,166(3):663-679
An extracellular thermostable xylanase from a newly isolated thermophilic Actinomadura sp. strain Cpt20 was purified and characterized. Based on matrix-assisted laser desorption–ionization time-of-flight mass
spectrometry analysis, the purified enzyme is a monomer with a molecular mass of 20,110.13 Da. The 19 residue N-terminal sequence
of the enzyme showed 84% homology with those of actinomycete endoxylanases. The optimum pH and temperature values for xylanase
activity were pH 10 and 80 °C, respectively. This xylanase was stable within a pH range of 5–10 and up to a temperature of
90 °C. It showed high thermostability at 60 °C for 5 days and half-life times at 90 °C and 100 °C were 2 and 1 h, respectively.
The xylanase was specific for xylans, showing higher specific activity on soluble oat-spelt xylan followed by beechwood xylan.
This enzyme obeyed the Michaelis–Menten kinetics, with the K
m and k
cat values being 1.55 mg soluble oat-spelt xylan/ml and 388 min−1, respectively. While the xylanase from Actinomadura sp. Cpt20 was activated by Mn2+, Ca2+, and Cu2+, it was, strongly inhibited by Hg2+, Zn2+, and Ba2+. These properties make this enzyme a potential candidate for future use in biotechnological applications particularly in
the pulp and paper industry. 相似文献
8.
Wei Zhao Aisheng Xiong Xiaoyan Fu Feng Gao Yongsheng Tian Rihe Peng 《Applied biochemistry and biotechnology》2010,162(8):2157-2165
To obtain a high level expression of phytase with favorable characteristics, a codon-optimized phytase gene from Citrobacter freundii was synthesized and transferred into Pichia pastoris. Small-scale expression experiments and activity assays were used to screen positive colonies. After purified by Ni2+–NTA agarose affinity column, the characterizations of the recombinant phytase were determined. The recombinant phytase (r-phyC)
had two distinct pH optima at 2.5 and 4.5 and an optimal temperature at 50 °C. It retained more than 80% activity after being
incubated under various buffer (pH 1.5–8.0) at 37 °C for 1 h. The specific activity, Km, and Vmax values of r-phyC for sodium phytate were 2,072 ± 18 U mg−1, 0.52 ± 0.04 mM, and 2,380 ± 84 U mg−1 min−1, respectively. The enzyme activity was significantly improved by 1 mM of K+, Ca2+, and Mg2+. These characteristics contribute to its potential application in feed industry. 相似文献
9.
Fu Qiang KeNing Sun NaiQing Zhang ShiRu Le XiaoDong Zhu JinHuo Piao 《Journal of Solid State Electrochemistry》2009,13(3):455-467
A-site-deficient perovskite cathode material La0.58Sr0.4Co0.2Fe0.8O3 − δ
(L58SCF) is coated on the yttria-stabilized zirconia electrolyte by screen-printing technique. Several key fabrication parameters
including selection of additives (binder and pore former), effect of coating thickness, sintering temperature and time on
the microstructure, and electrochemical performance of cathode are investigated by scanning electron microscopy and electrochemical
impedance spectroscopy. We study the microstructure and the electrochemical property of the cathode with different kinds of
additives. Results show that the cathode possesses fine microstructure, enough porosity, and ideal electrochemical property
when polyvinyl butyral serves as both binder and pore former in the cathode. The cathode with three screen-printing coats
(thickness 28 ± 7 μm, weight 6.07 ± 0.72 mg cm−2) sintering at 1,000 °C for 2 h shows lower polarization resistance of 0.183 Ω cm2 at 800 °C. Based on the optimized parameters, the polarization resistances of the L58SCF–Ce0.8Gd0.2O1.9 – δ
composite cathode display the R
p values of 0.067 Ω cm2 at 800 °C, 0.106 Ω cm2 at 750 °C, 0.225 Ω cm2 at 700 °C, and 0.550 Ω cm2 at 650 °C. 相似文献
10.
Wanwisa Moon-ai Ploypat Niyomploy Ruethairat Boonsombat Polkit Sangvanich Aphichart Karnchanatat 《Applied biochemistry and biotechnology》2012,166(8):2138-2155
Superoxide dismutase (SOD, EC 1.15.1.1) is a metalloenzyme or antioxidant enzyme that catalyzes the disproportionation of
the harmful superoxide anionic radical to hydrogen peroxide and molecular oxygen. Due to its antioxidative effects, SOD has
long been applied in medicinal treatment, cosmetic, and other chemical industries. Fifteen Zingiberaceae plants were tested
for SOD activity in their rhizome extracts. The crude homogenate and ammonium sulfate cut fraction of Curcuma aeruginosa were found to contain a significant level of SOD activity. The SOD enzyme was enriched 16.7-fold by sequential ammonium sulfate
precipitation, diethylaminoethyl cellulose ion exchange, and Superdex 75 gel filtration column chromatography. An overall
SOD yield of 2.51 % with a specific activity of 812.20 U/mg was obtained. The enriched SOD had an apparent MW of 31.5 kDa,
as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and a pH and temperature optima of 4.0 and 50 °C.
With nitroblue tetrazolium and riboflavin as substrates, the K
m values were 57.31 ± 0.012 and 1.51 ± 0.014 M, respectively, with corresponding V
max values of 333.7 ± 0.034 and 254.1 ± 0.022 μmol min−1 mg protein−1. This SOD likely belongs to the Fe- or Mn-SOD category due to the fact that it was insensitive to potassium cyanide or hydrogen
peroxide inhibition, but was potentially weakly stimulated by hydrogen peroxide, and stimulated by Mn2+and Fe2+ ions. Moreover, this purified SOD also exhibited inhibitory effects on lipopolysaccharide-induced nitric oxide production
in cultured mouse macrophage cell RAW 264.7 in a dose-dependent manner (IC50 = 14.36 ± 0.15 μg protein/ml). 相似文献
11.
Assamoi Allah Antoine Destain Jacqueline Philippe Thonart 《Applied biochemistry and biotechnology》2010,160(1):50-62
There is an increasing interest for the organic residues from various sectors of agriculture and industries over the past
few decades. Their application in the field of fermentation technology has resulted in the production of bulk chemicals and
value-added products such as amino acid, enzymes, mushroom, organic acids, single-cell protein, biologically active secondary
metabolites, etc. (Ramachandran et al., Bioresource Technology 98:2000–2009, 2007). In this work, the production of extracellular xylanase by the fungus Penicillium canescens was investigated in solid-state fermentation using five agro-industrial substrates (soya oil cake, soya meal, wheat bran,
whole wheat bran, and pulp beet). The best substrate was the soya oil cake. In order to optimize the production, the most
effective cultivation conditions were investigated in Erlenmeyer flasks and in plastic bags with 5 and 100 g of soya oil cake,
respectively. The initial moisture content, initial pH, and temperature of the culture affected the xylanase synthesis. The
optimal fermentation medium was composed by soya oil cake crushed to 5 mm supplemented with 3% and 4% (w/w) of casein peptone and Na2HPO4.2H2O. After 7 days of incubation at 30 °C and under 80% of initial moisture, a xylanase production level of 18,895 ± 778 U/g
(Erlenmeyer flasks) and 9,300 ± 589 U/g (plastic bags) was reached. The partially purified enzyme recovered by ammonium sulfate
fractionation was completely stable at freezing and refrigeration temperatures up to 6 months and reasonably stable at room
temperature for more than 3 months. 相似文献
12.
Anushree Purushottam Khandale Shyam Shashibhushan Bhoga 《Journal of Solid State Electrochemistry》2012,16(1):341-352
The solid solubility limit of Ce in Nd2–x
Ce
x
CuO4 ± δ
, prepared by sol–gel process, is established up to x = 0.2. The transition from negative temperature coefficient to positive temperature coefficient, within the solid solubility
region, is observed at 620 °C. The area-specific-resistance (ASR) is optimized for electrochemical cell sintered at 800 °C.
ASR enhances with increase in sintering temperature of cell. ASR value of 0.93 ohm cm2 at 700 °C, determined by electrochemical impedance spectroscopy is comparable against that by voltage versus current (V–I)
characteristics at 0.98 ohm cm2 at the same temperature. Electrochemical performance and ASR of Nd1.8Ce0.2CuO4 ± δ
is improved when prepared by sol–gel route over solid-state reaction, which is attributed to uniform size and shape of nanocrystalline
grains. 相似文献
13.
Yun Wang Jin-Zhu Song Qian Yang Zhi-Hua Liu Xiao-Mei Huang Yan Chen 《Applied biochemistry and biotechnology》2010,162(3):843-854
A gene encoding chitin deacetylase was cloned by polymerase chain reaction from Aspergillus nidulans. Sequencing result showed 40% homology to the corresponding gene from Colletotrichum lindemuthianum. The complete gene contains an open reading frame of 747 nucleotides encoding a sequence of 249 amino acid residues. The
chitin deacetylase gene was subcloned into a pET28a expression vector and expressed in Escherichia coli BL21 and then purified by metal affinity chromatography using a His-bind column. The purified chitin deacetylase demonstrated
an activity of 0.77 U ml−1 for the glycol chitin substrates, and its specific activity was 4.17 U mg−1 for it. The optimal temperature and pH of the purified enzyme were 50 °C and 8.0, respectively. When glycol chitin was used
as the substrate, K
m was 4.92 mg ml−1, and K
cat showed 6.25 s−1, thus the ratio of K
cat and K
m was 1.27 ml s−1 mg−1. The activity of chitin deacetylase was affected by a range of metal ions and ethylenediaminetetraacetic acid. 相似文献
14.
Wanli Liu Pengjun Shi Qiang Chen Peilong Yang Guozeng Wang Yaru Wang Huiying Luo Bin Yao 《Applied biochemistry and biotechnology》2010,162(1):1-12
A xylanase-encoding gene, xyn11F63, was isolated from Penicillium sp. F63 CGMCC1669 using degenerated polymerase chain reaction (PCR) and thermal asymmetric interlaced (TAIL)-PCR techniques.
The full-length chromosomal gene consists of 724 bp, including a 73-bp intron, and encodes a 217 amino acid polypeptide. The
deduced amino acid sequence of xyn11F63 shows the highest identity of 70% to the xylanase from Penicillium sp. strain 40, which belongs to glycosyl hydrolases family 11. The gene was overexpressed in Pichia pastoris, and its activity in the culture medium reached 516 U ml−1. After purification to electrophoretic homogeneity, the enzyme showed maximal activity at pH 4.5 and 40°C, was stable at
acidic buffers of pH 4.5–9.0, and was resistant to proteases (proteinase K, trypsin, subtilisin A, and α-chymotrypsin). The
specific activity, K
m, and V
max for oat spelt xylan substrate was 7,988 U mg−1, 22.2 mg ml−1, and 15,105.7 μmol min−1 mg−1, respectively. These properties make XYN11F63 a potential economical candidate for use in feed and food industrial applications. 相似文献
15.
Dengeti Shrinivas Gunashekaran Savitha Kumar Raviranjan Gajanan Ramchandra Naik 《Applied biochemistry and biotechnology》2010,162(7):2049-2057
A highly thermostable alkaline xylanase was purified to homogeneity from culture supernatant of Bacillus sp. JB 99 using DEAE-Sepharose and Sephadex G-100 gel filtration with 25.7-fold increase in activity and 43.5% recovery.
The molecular weight of the purified xylanase was found to be 20 kDA by SDS-PAGE and zymogram analysis. The enzyme was optimally
active at 70 °C, pH 8.0 and stable over pH range of 6.0–10.0.The relative activity at 9.0 and 10.0 were 90% and 85% of that
of pH 8.0, respectively. The enzyme showed high thermal stability at 60 °C with 95% of its activity after 5 h. The K
m and V
max of enzyme for oat spelt xylan were 4.8 mg/ml and 218.6 μM min−1 mg−1, respectively. Analysis of N-terminal amino acid sequence revealed that the xylanase belongs to glycosyl hydrolase family
11 from thermoalkalophilic Bacillus sp. with basic pI. Substrate specificity showed a high activity on xylan-containing substrate and cellulase-free nature. The hydrolyzed product
pattern of oat spelt xylan on thin-layer chromatography suggested xylanase as an endoxylanase. Due to these properties, xylanase
from Bacillus sp. JB 99 was found to be highly compatible for paper and pulp industry. 相似文献
16.
Columns containing immobilized low-density lipoprotein (LDL) were prepared for the analysis of drug interactions with this
agent by high-performance affinity chromatography (HPAC). R/S-Propranolol was used as a model drug for this study. The LDL columns gave reproducible binding to propranolol over 60 h of
continuous use in the presence of pH 7.4 0.067 M potassium phosphate buffer. Experiments conducted with this type of column
through frontal analysis indicated that two types of interactions were occurring between R-propranolol and LDL, while only a single type of interaction was observed between S-propranolol and LDL. The first type of interaction, which was seen for both enantiomers, involved non-saturable binding;
this interaction had an overall affinity (nK
a) of 1.9 (±0.1) × 105 M−1 for R-propranolol and 2.7 (±0.2) × 105 M−1 for S-propranolol at 37 °C. The second type of interaction was observed only for R-propranolol and involved saturable binding that had an association equilibrium constant (K
a) of 5.2 (±2.3) × 105 M−1 at 37 °C. Similar differences in binding behavior were found for the two enantiomers at 20 °C and 27 °C. This is the first
known example of stereoselective binding of drugs by LDL or other lipoproteins. This work also illustrates the ability of
HPAC to be used as a tool for characterizing mixed-mode interactions that involve LDL and related binding agents. 相似文献
17.
A new adsorbent is proposed for the solid-phase extraction of phenol and 1-naphthol from polluted water. The adsorbent (TX-SiO2) is an organosilica composite made from a bifunctional immobilized layer comprising a major fraction (91%) of hydrophilic
diol groups and minor fraction (9%) of the amphiphilic long-chain nonionic surfactant Triton X-100 (polyoxyethylated isooctylphenol)
(TX). Under static conditions phenol was quantitatively extracted onto TX-SiO2 in the form of a 4-nitrophenylazophenolate ion associate with cetyltrimethylammonium bromide. The capacity of TX-SiO2 for phenol is 2.4 mg g−1 with distribution coefficients up to 3.4 × 104 mL g−1; corresponding data for 1-naphthol are 1.5 mg g−1 and 3 × 103 mL g−1. The distribution coefficient does not change significantly for solution volumes of 0.025–0.5 L and adsorbent mass less than
0.03 g; 1–90 μg analyte can be easily eluted by 1–3 mL acetonitrile with an overall recovery of 98.2% and 78.3% for phenol
and 1-naphthol, respectively. Linear correlation between acetonitrile solution absorbance (A
540) and phenol concentration (C) in water was found according to the equation A
540 = (6 ± 1) × 10−2 + (0.9 ± 0.1)C (μmol L−1) with a detection range from 1 × 10−8 mol L−1 (0.9 μL g−1) to 2 × 10−7 mol L−1 (19 μL g−1), a limit of quantification of 1 μL g−1 (preconcentration factor 125), correlation coefficient of 0.936, and relative standard deviation of 2.5%. A solid-phase colorimetric
method was developed for quantitative determination of 1-naphthol on adsorbent phase using scanner technology and RGB numerical
analysis. The detection limit of 1-naphthol with this method is 6 μL g−1 while the quantification limit is 20 μL g−1. A test system was developed for naked eye monitoring of 1-naphthol impurities in water. The proposed test kit allows one
to observe changes in the adsorbent color when 1-naphthol concentration in water is 0.08–3.2 mL g−1. 相似文献
18.
Two xylanases from the crude culture filtrate of Penicillium sclerotiorum were purified to homogeneity by a rapid and efficient procedure, using ion-exchange and molecular exclusion chromatography.
Molecular masses estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 23.9 and 33.1 kDa for xylanase
I and II, respectively. The native enzymes’ molecular masses of 23.8 and 30.8 kDa were estimated for xylanase I and II, respectively,
by molecular exclusion chromatography. Both enzymes are glycoproteins with optimum temperature and pH of 50 °C and pH 2.5
for xylanase I and 55 °C and pH 4.5 for xylanase II. The reducing agents β-mercaptoethanol and dithio-treitol enhanced xylanase
activities, while the ions Hg2+ and Cu2+ as well the detergent SDS were strong inhibitors of both enzymes, but xylanase II was stimulated when incubated with Mn2+. The K
m value of xylanase I for birchwood xylan and for oat spelt xylan were 6.5 and 2.6 mg mL−1, respectively, whereas the K
m values of xylanase II for these substrates were 26.61 and 23.45 mg mL−1. The hydrolysis of oat spelt xylan by xylanase I released xylobiose and larger xylooligosaccharides while xylooligosaccharides
with a decreasing polymerization degree up to xylotriose were observed by the action of xylanase II. The present study is
among the first works to examine and describe an extracellular, highly acidophilic xylanase, with an unusual optimum pH at
2.5. Previously, only one work described a xylanase with optimum pH 2.0. This novel xylanase showed interesting characteristics
for biotechnological process such as feed and food industries. 相似文献
19.
To investigate the production of cellulases and xylanases from Penicillium echinulatum 9A02S1, solid-state fermentation (SSF) was performed by using different ratios of sugar cane bagasse (SCB) and wheat bran
(WB). The greatest filter paper activity obtained was 45.82 ± 1.88 U gdm−1 in a culture containing 6SCB/4WB on the third day. The greatest β-glucosidase activities were 40.13 ± 5.10 U gdm−1 obtained on the third day for the 0SCB/10WB culture and 29.17 ± 1.06 U gdm−1 for the 2SCB/8WB culture. For endoglucanase, the greatest activities were 290.47 ± 43.57 and 276.84 ± 15.47 U gdm−1, for the culture 6SCB/4WB on the fourth and fifth days of cultivation, respectively. The greatest xylanase activities were
found on the third day for the cultures 6SCB/4WB (36.38 ± 5.38 U gdm−1) and 4SCB/6WB (37.87 ± 2.26 U gdm−1). In conclusion, the results presented in this article showed that it was possible to obtain large amounts of cellulases
and xylanases enzymes using low-cost substrates, such as SCB and WB. 相似文献
20.
Yanhua Li Kelong Huang Dongming Zeng Suqin Liu Zufu Yao 《Journal of Solid State Electrochemistry》2010,14(7):1205-1211
RuO2/Co3O4 thin films with different RuO2 content were successfully prepared on fluorine-doped tin oxide coated glass plate substrates by spray pyrolysis method, and
their capacitive behavior was investigated. Electrochemical property was performed by cyclic voltammetry, constant current
charge/discharge, and electrochemical impedance spectra. The capacitive performance of RuO2/Co3O4 thin films with different RuO2 content corresponded to a contribution from a main pseudocapacitance and an additional electric double-layer capacitance.
The specific capacitance of pure Co3O4, 15.5%, 35.6%, and 62.3% RuO2 composites at the current density of 0.2 A g−1 were 394 ± 8, 453 ± 9, 520 ± 10, and 690 ± 14 F g−1, respectively; 62.3% RuO2 composite presented the highest specific capacitance value at various current densities, whereas 35.6% RuO2 composite exhibited not only the largest specific capacitance contribution from RuO2 (C
sp
RuO2) at the current density of 0.5, 1.0, 1.5, and 2.0 A g−1 but also the highest specific capacitance retention ratio (46.3 ± 2.8%) at the current density ranging from 0.2 to 2.0 A g−1. Electrochemical impedance spectra showed that the contact resistance dropped gradually with the decrease of RuO2 content, and the charge-transfer resistance (R
ct) increased gradually with the decrease of RuO2 content. 相似文献