共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
The phylogenetic tree of the partial elongation factor-1 alpha gene fits better than the partial 18S rDNA for generic classification. From the results of the molecular tree and analysis of morphological characters, Petriella setifera LH was identified. It can be induced to produce carboxymethyl cellulase (CMCase). The crude CMCase only shows a 44.1-kDa band by activity staining after SDS-PAGE. It is optimally active at 55°C and pH 6.0, and is stable from pH 5.0–8.0 and at 45°C or below. The crude CMCase, which is not affected by Co2+, is strongly activated in the presence of 10 mM Na+, K+, Ca2+, Mg2+, EDTA, and Mn2+. It is strongly inhibited by 10 mM Fe2+, Pb2+, Al3+, Zn2+, Ag+, Fe3+, and Cu2+. When compared with denim treatment by Novoprime A800 (a commercial neutral cellulase), crude CMCase exhibits a similar fabric weight loss and indigo dye removal. These results indicate that crude CMCase has potential application in denim biostoning. 相似文献
3.
Asparaginase production by a mesophilic strain ofErwinia sp. was examined; the maximum of activity was found at 40°C and pH 8.5. Among the various carbon sources, mannitol was shown
to be the best for production of activity. Inorganic nitrogen sources were better than the organic ones. The enzyme activity
was not inhibited by 10 mmol/L metal ions (Na+, K+, Mg2+, Ca2+, Ba2+, Co2+, Ni2+, Zn2+); the activity was strongly inhibited by addition of EDTA.l-Arginine,dl-alanine,l-asparagine andl-glutamine stimulated thel-asparaginase production by 3.9, 1.7, 4.3 and 4.0 fold, respectively. The combination ofl-arginine,l-asparagine andl-glutamine synergistically stimulated the asparaginase up to 5.8 fold. 相似文献
4.
Yukio Fujisawa ShirafujiHideo Shirafuji Toshihiko Kanzaki 《Bioscience, biotechnology, and biochemistry》2013,77(6):1303-1309
Cephalosporin C acetyl-hydrolase, which had not yet been found in Cephalosporium acremonium cultures, was partially purified from the culture fluid of the mutant No. 81 by ammonium sulfate fractionation, dialysis and DEAE-cellulose column chromatography. The optimum pH and temperature of the enzyme reaction were found to be about 8.0 and 50°C, respectively. The enzyme activity was hardly affected by Mg2+, Mn2+, Zn2+, Co2+, Ni2+, Na+, K+, EDTA, PCMB and 2,4-dinitrophenol, but markedly inhibited by diisopropylfluoro-phosphate at 1 mm. The product formed from cephalosporin C by the enzyme reaction was proved to be deacetylcephalosporin C by physical and chemical analyses and chromatographic behaviors. 相似文献
5.
Purpose of work The purpose of this study is to report a thermostable λ-carrageenase that can degrade λ-carrageenan yielding neo-λ-carrabiose at 75 °C. A thermophilic strain Lc50-1 producing λ-carrageenase was isolated from a hot spring in Indonesia and identified as a Bacillus sp. The λ-carrageenase, Cga-L50, with an apparent molecular weight of 37 kDa and a specific activity of 105 U/mg was purified from the culture supernatant. The optimum pH and temperature of Cga-L50 were 8.0 and 75 °C, respectively. The enzyme was stable from pH 6–9 and retained ~50 % activity after holding at 85 °C for 10 min. Significant activation of Cga-L50 was observed with K+, Ca2+, Co2+, and Na+; whereas, the enzyme activity was inhibited by Sr2+, Mn2+, Fe2+, Cu2+,Cd2+, Mg2+, and EDTA. Cga-L50 is an endo-type λ-carrageenase that hydrolyzes β-1,4-linkages of λ-carrageenan, yielding neo-λ-carrabiose as the main product. This study is the first to present evidence of thermostable λ-carrageenase from hot spring bacteria. 相似文献
6.
Effects of the ionophore A23187 on isolated broken and intact chloroplasts in the pH range of 6.2 to 7.6 have been studied. In both types of chloroplasts, uncoupling of photosynthetic electron transport by A23187 (6–10 μm) was mediated either by Mg2+ or—in the absence of divalent cations (i.e., when EDTA was added to the medium)—by high concentrations of Na+, but not of K+ ions. At increased concentrations of the ionophore (above about 10 μm) and high pH (7.2 to 7.6), uncoupling in broken chloroplasts was also mediated by K+ ions. The inhibition of the energy-dependent slow decline of chlorophyll fluorescence in intact chloroplasts by the ionophore (which denotes uncoupling) is reversed by EDTA in the presence of K+, but not of Na+ ions. In 3-(3′,4′-dichlorophenyl)1,1-dimethylurea-poisoned intact chloroplasts, the yield of variable chlorophyll fluorescence is lowered by A23187 + EDTA and increased again by addition of NaCl or KCl. Chlorophyll fluorescence spectra at 77 °K of intact chloroplasts incubated with A23187 + EDTA indicated that the distribution of excitation energy had changed in favor of photosystem I, as expected from a depletion of Mg2+. This change was reversed by MgCl2+, KCl, or NaCl. From a comparison of low-temperature fluorescence spectra of broken and intact chloroplasts at different levels of Mg2+ in the medium, the concentration of free Mg2+ in the stroma of the intact chloroplasts at pH 7.6 in the dark was estimated at 1 to 4 mm. The results show that in chloroplasts the specificity of A23187 for divalent cations is limited. In the presence of EDTA, the ionophore mediates fast exchange across thylakoid membranes, whereas K+ is transferred much less efficiently. Both Na+ and K+ ions seem to be transported readily across the chloroplast envelope by the action of the ionophore, leading to an exchange of Mg2+ for monovalent cations at the thylakoid membrane surfaces in intact chloroplasts. 相似文献
7.
An extracellular α-amylase produced by a cassava-fermenting strain ofMicrococcus luteus was purified 26-fold by gel filtration and ion-exchange chromatography. The molar mass was estimated to be approximately
56 kDa. The optimum temperature of the enzyme was 30°C, optimum pH 6.0 and optimum substrate concentration was 0.6% (W/V). Treatment of the enzyme at 70°C for 10 min resulted in 70% loss of activity. The activation energy was determined to be
34.8 kJ/mol. The activity of the enzyme was enhanced by Mg2+, Ca2+, K+, Na+ and inhibited by EDTA, KCN and citric acid. The enzyme may find some application in local food processing. 相似文献
8.
Gramicidin S (GS) inhibition of germination outgrowth ofBacillus brevis spores was reversed completely by a short pretreatment with sodium dodecyl sulfate, moderately by ethanol or by incubation at pH 10 but not by incubation at pH 4. Of five metal ions tested (Na+, Mg2+, Fe2+, Cu2+, Ca2+), only Ca2+ reversed GS inhibition. When Ca2+ (but not the other four metal ions) was added to the growth medium, there was a considerable portion of the biosynthesized GS found in the extracellular fluid. These findings are interpreted in terms of the binding of GS to the external layers of theB. brevis spore. 相似文献
9.
Characterization of a recombinant thermostable xylanase from deep-sea thermophilic Geobacillus sp. MT-1 in East Pacific 总被引:1,自引:0,他引:1
A novel xylanase-producing thermophilic strain MT-1 was isolated from a deep-sea hydrothermal field in east Pacific. A xylanase gene encoding 331 amino-acid peptide from this isolate was cloned and expressed in Escherichia
coli. The recombinant xylanase exhibited maximum activity at 70°C and had an optimum pH of 7.0. It was active up to 90°C and showed activity over a wide pH ranging from 5.5 to 10.0. The crude xylanase presented similar properties in temperature and pH to those of the recombinant xylanase. The recombinant xylanase was stable in 1 mM of enzyme inhibitors (PMSF, EDTA, 2-ME or DTT) and in 0.1% detergents (Tween 20, Chaps or Triton X-100), whereas, it was strongly inhibited by sodium dodecyl sulfate (SDS) (1 mM). In addition, its catalytic function was stable in the presence of Li+, Na+ or K+. However, it was strongly inhibited by Ni2+, Mn2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+ and Al3+ (1 or 0.1 mM). The K
m and V
max of the recombinant xylanase for oat spelt xylan were calculated to be 1.579 mg/ml and 289 μmol/(min • mg), respectively. Our study, therefore, presented a rapid overexpression and purification of xylanase from deep-sea thermophile aimed at improving the enzyme yield for industrial applications and scientific research. 相似文献
10.
Low concentrations of chelating agents such as EDTA prevent the air oxidation of vanadyl (VO2+, +4 oxidation state) to vanadate (VO3?, +5 oxidation state). Under these conditions, the ionophore A23187 mediates the rapid entry of vanadyl into human erythrocytes. In the presence of A23187, vanadyl at concentrations in excess of EDTA gives rise to a dramatic increase in K+ permeability, which is very similar to the Gardos Ca2+-induced K+ permeability increase with respect to ion selectivity, response to inhibitors, effects of pH, and stimulation by external K+. In ultrapure media with very low Ca2+, however, vanadyl has no effect on K+ permeability. These experiments suggest that Ca2+ is displaced from EDTA by vanadyl and then enters the cell via A23187 where it triggers the increase in K+ permeability. This hypothesis is confirmed by experiments demonstrating that vanadyl does displace Ca2+ from EDTA. Vanadate, an inhibitor of Ca2+-ATPase, causes a selective increase in K+ permeability in metabolically depleted cells, but the increase is abolished by low concentrations of EDTA, indicating that this effect is also due to entry of extracellular Ca2+. Earlier observations of effects of vanadyl and vanadate on erythrocyte K+ permeability can thus be explained on the basis of inhibition of the Ca2+ pump by vanadium, leading to an increase in intracellular Ca2+ concentration. 相似文献
11.
Yasuo Kondo 《Bioscience, biotechnology, and biochemistry》2013,77(9):2377-2378
The physico-chemical characteristics of purified arginine kinases from prawn and swimming crab were examined. The molecular weights of prawn and swimming crab enzymes were 40,500 and 40,000, respectively. Amino acid analysis indicated that there were some differences in the contents of proline, glycine, methionine, and lysine. The other amino acid compositions of these enzymes resembled each other.Both enzymes were stable up to 20°C when they were treated for 10 min at various temperature levels. The enzymes lost their activities at temperatures higher than 25°C. They were more stable at pH 8.0 than pH 7.0. The optimum temperature for the enzyme of prawn was about 42°C and that for swimming crab was about 40°C. The pH optima for the activity of arginine kinase of prawn in the forward and in the reverse reactions were found to be 9.0 and 6.1, respectively. For the swimming crab, the similar optimum pHs at 9.2 in the forward reaction and 5.8 in the reverse reaction were observed. Both enzymes were activated most strongly with Mg2 + and Mn2 + followed by Ca2 +, Co2 +, and Fe2 +. The enzymes were not activated by Sr2 +, Cu2 +, or Zn2 +.The optimum molar ratio of Mg2 +: ATP in the forward reaction of prawn and swimming crab was found to be 1:1, and the molar ratio of Mg2 + : ADP in the reverse reaction was 4:1 in both cases. Kinetic studies indicated that dissociation constants were rather different. In the prawn, dissociation constants for arginine, ATP, AP, and ADP were 0.19,0.31, 0.67, and 0.29 mM, respectively, but in the swimming crab, they were 0.10, 0.18, 0.22, and 0.11 mM, respectively. 相似文献
12.
Sandra Regina B. R. Sella Carla Masetti Luis Felipe M. Figueiredo Luciana P. S. Vandenberghe João Carlos Minozzo Carlos Ricardo Soccol 《Biotechnology and Bioprocess Engineering》2013,18(1):75-87
A novel cost-effective Bacillus atrophaeus Sterilization Bioindicator System (BIS) with a high quality and performance was developed from a soybean byproduct and compared with the commercial BIS. It was composed of recovery medium and dry-fermented spores with sand as the support. The BIS was developed and optimized using a sequential experimental design strategy. The recovery medium contained soluble starch (1.0 g/L), soybean molasses (30.0 g/L), tryptone (40.0 g/L), and bromothymol blue (0.02 g/L) at pH 8.5. The solid-state fermentation conditions of the bioreactor and environmental humidity had no significant effects on the spore yield and dry-heat resistance. The only substrate mineral that showed a positive effect was Mn2+, allowing Mg2+, K+, and Ca2+ to be eliminated from the formulation. Validation of optimized medium indicated D 160°C = 6.8±1.0 min (3.6 min more than the minimum) and spore yield = 2.3 ± 0.5 × 109 CFU/g dry sand (10,000 × initial values). BIS performance resulted in D 160°C = 6.6 ± 0.1 min. Sporulation and germination kinetics allowed the sporulation process to be reduced to three days, and the growth of heat-damaged spores was sufficient to achieve visual identification of a non-sterile BIS within 21 h. Process economics was a minimum of 23.9%, and process cycle time was reduced from 29 to 15 days. The new BIS parameters demonstrated compliance to all regulatory requirements. No studies have yet described a BIS production from soybean molasses. 相似文献
13.
Babu Joseph Nitisha Shrivastava Pramod W. Ramteke 《Journal of Genetic Engineering and Biotechnology》2012,10(1):137-144
A psychrophilic bacterium producing cold-active lipase upon growth at low temperature was isolated from the soil samples of Gangotri glacier and identified as Microbacterium luteolum. The bacterial strain produced maximum lipase at 15 °C, at a pH of 8.0. Beef extract served as the best organic nitrogen source and ammonium nitrate as inorganic for maximum lipase production. Castor oil served as an inducer and glucose served as an additional carbon source for production of cold-active lipase. Ferric chloride as additional mineral salt in the medium, highly influenced the lipase production with an activity of 8.01 U ml?1. The cold-active lipase was purified to 35.64-fold by DEAE-cellulose column chromatography. It showed maximum activity at 5 °C and thermostability up to 35 °C. The purified lipase was stable between pH 5 and 9 and the optimal pH for enzymatic hydrolysis was 8.0. Lipase activity was stimulated in presence of all the solvents (5%) tested except with acetonitrile. Lipase activity was inhibited in presence of Mn2+, Cu2+, and Hg2+; whereas Fe+, Na+ did not have any inhibitory effect on the enzyme activity. The purified lipase was stable in the presence of SDS; however, EDTA and dithiothreitol inhibited enzyme activity. Presence of Ca2+ along with inhibitors stabilized lipase activity. The cold active lipase thus exhibiting activity and stability at a low temperature and alkaline pH appears to be practically useful in industrial applications especially in detergent formulations. 相似文献
14.
Carel J. van Oss 《Preparative biochemistry & biotechnology》2013,43(2):187-188
An ionically unbound and thermostable polyphenol oxidase (PPO) was extracted from the leaf of Musa paradisiaca. The enzyme was purified 2.54-fold with a total yield of 9.5% by ammonium sulfate precipitation followed by Sephadex G-100 gel filtration chromatography. The purified enzyme exhibited a clear single band on native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate (SDS) PAGE. It was found to be monomeric protein with molecular mass of about 40 kD. The zymographic study using crude extract as enzyme source showed a very clear band around 40 kD and a faint band at around 15 kD, which might be isozymes. The enzyme was optimally active at pH 7.0 and 50°C temperature. The enzyme was active in wide range of pH (4.0–9.0) and temperature (30–90°C). From the thermal inactivation studies in the range 60–75°C, the half-life (t1/2) values of the enzyme ranged from 17 to 77 min. The inactivation energy (Ea) value of PPO was estimated to be 91.3 kJ mol?1. It showed higher specificity with catechol (Km = 8 mM) as compared to 4-methylcatechol (Km = 10 mM). Among metal ions and reagents tested, Cu2+, Fe2+, Hg2+, Mn2+, Ni2+, protocatechuic acid, and ferrulic acid enhanced the enzyme activity, while K+, Na+, Co2+, kojic acid, ascorbic acid, ethylenediamine tetraacetic acid (EDTA), sodium azide, β-mercaptoethanol, and L-cysteine inhibited the activity of the enzyme. 相似文献
15.
Jin-Beom Si Eun-Ju Jang Dimitris Charalampopoulos Young-Jung Wee 《Biotechnology and Bioprocess Engineering》2018,23(2):176-182
An ammonium sulfate precipitation of fermentation broth produced by Bacillus subtilis FBL-1 resulted in 2.9-fold increase of specific protease activity. An eluted protein fraction from the column chromatographies using DEAE-Cellulose and Sephadex G-75 had 94.2- and 94.9-fold higher specific protease activity, respectively. An SDS-PAGE revealed a band of purified protease at approximately 37.6 kDa. Although purified protease showed the highest activity at 45°C and pH 9.0, the activity remained stable in temperature range from 30 to 50°C and pH range from 7.0 to 9.0. Protease activity was activated by metal ions such as Ca2+, Mg2+, Mn2+, Fe2+, Ca2+ and K+, but 10 mM Fe3+ significantly inhibited enzyme activity (53%). Protease activity was inhibited by 2 mM EDTA as a metalloprotease inhibitor, but it showed good stability against surfactants and organic solvents. The preferred substrates for protease activity were found to be casein (100%) and soybean flour (71.6%). 相似文献
16.
Nguyen Thi Minh H Durand A Loison P Perrier-Cornet JM Gervais P 《Applied microbiology and biotechnology》2011,90(4):1409-1417
Bacillus subtilis(B. subtilis) cells were placed in various environmental conditions to study the effects of aeration, water activity of the medium, temperature,
pH, and calcium content on spore formation and the resulting properties. Modification of the sporulation conditions lengthened
the growth period of B. subtilis and its sporulation. In some cases, it reduced the final spore concentration. The sporulation conditions significantly affected
the spore properties, including germination capacity and resistance to heat treatment in water (30 min at 97°C) or to high
pressure (60 min at 350 MPa and 40°C). The relationship between the modifications of these spore properties and the change
in the spore structure induced by different sporulation conditions is also considered. According to this study, sporulation
conditions must be carefully taken into account during settling sterilization processes applied in the food industry. 相似文献
17.
Fang Gong Tong Zhang Zhenming Chi Jun Sheng Jing Li Xianghong Wang 《Biotechnology and Bioprocess Engineering》2008,13(5):533-539
The extracellular inulinase of the marine yeast Pichia guilliermondii strain 1 was purified to homogeneity resulting in a 7.2-fold increase in specific inulinase activity. The molecular mass
of the purified enzyme was estimated to be 50.0 kDa. The optimal pH and temperature for the purified enzyme were 6.0 and 60°C,
respectively. The enzyme was activated by Mn2+, Ca2+, K+, Li+, Na+, Fe3+, Fe2+, Cu2+, and Co2+, but Mg2+, Hg2+, and Ag+ inhibited activity. The enzyme was strongly inhibited by phenylmethanesulphonyl fluoride (PMSF), iodoacetic acid, EDTA, and
1, 10-phenanthroline. The K
m and V
max values of the purified inulinase for inulin were 21.1 mg/mL and 0.08 mg/min, respectively. A large number of monosaccharides
were detected after the hydrolysis of inulin. The deduced protein sequence from the cloned P. guilliermondii strain 1 inulinase gene contained the consensus motifs R-D-P-K-V-F-W-H and W-M-N-D-P-N-G, which are conserved among the inulinases
from other microorganisms. 相似文献
18.
A cold-active alkaline amylase producer Bacillus subtilis N8 was isolated from soil samples. Amylase synthesis optimally occurred at 15°C and pH 10.0 on agar plates containing starch. The molecular weight of the enzyme was found to be 205?kDa by performing SDS-PAGE. While the enzyme exhibited the highest activity at 25°C and pH 8.0, it was highly stable in alkaline media (pH 8.0–12.0) and retained 96% of its original activity at low temperatures (10–40°C) for 24?hr. While the amylase activity increased in the presence of β-mercaptoethanol (103%); Ba2+, Ca2+, Na+, Zn2+, Mn2+, H2O2, and Triton X-100 slightly inhibited the activity. The enzyme showed resistance to some denaturants: such as SDS, EDTA, and urea (52, 65, and 42%, respectively). N8 α-amylase displayed the maximum remaining activity of 56% with 3% NaCl. The major final products of starch were glucose, maltose, and maltose-derived oligosaccharides. This novel cold-active α-amylase has the potential to be used in the industries of detergent and food, bioremediation process and production of prebiotics. 相似文献
19.
Cell-free supernatant of pelleted zoospores was found to be more suitable for maintaining viable zoospores and developed cysts
than the supernatant of mature cysts. Conductivity and pH measurements indicated quantitative changes in the ionic composition
of a suspension ofP. infestans zoospores during their conversion into cysts. An increase in conductivity in the incipient cyst suspension was followed by
a decrease of conductivity in the maturing cyst suspension. The conductivity changes correlated closely with K+ fluxes which, in turn, coincided with the reverse, but stoichiometrically smaller, H+ fluxes. Zoospores treated with 1.5 μmol/L DCCD (an inhibitor of plasma membrane H+-ATPase) or 100 mmol/L Li+ (an inhibitor of cell motility) released predominantly K+ and other cations and their O2 consumption decreased. The H+/K+ exchange is therefore very probably associated with an operation of the plasma membrane H+-ATPase. The differential decrease in respiration caused by DCCD and Li+ was used to estimate the energy demand for cell motility and spore development. 相似文献
20.
Dattatray Bedade Jan Deska Sandip Bankar Samir Bejar Rekha Singhal Salem Shamekh 《Preparative biochemistry & biotechnology》2013,43(6):549-555
AbstractTruffles are symbiotic hypogeous edible fungi (form of mushroom) that form filamentous mycelia in their initial phase of the growth cycle as well as a symbiotic association with host plant roots. In the present study, Tuber maculatum mycelia were isolated and tested for extracellular amylase production at different pH on solid agar medium. Furthermore, the mycelium was subjected to submerged fermentation for amylase production under different culture conditions such as variable carbon sources and their concentrations, initial medium pH, and incubation time. The optimized conditions after the experiments included soluble starch (0.5% w/v), initial medium pH of 7.0, and incubation time of 7 days, at room temperature (22?±?2?°C) under static conditions which resulted in 1.41?U/mL of amylase. The amylase thus obtained was further characterized for its biocatalytic properties and found to have an optimum activity at pH 5.0 and a temperature of 50?°C. The enzyme showed good thermostability at 50?°C by retaining 98% of the maximal activity after 100?min of incubation. The amylase activity was marginally enhanced in presence of Cu2+ and Na+ and slightly reduced by K+, Ca2+, Fe2+, Mg2+, Co2+, Zn2+, and Mn2+ ions at 1?mM concentration. 相似文献