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1.
An extracellular, halophilic, alkalithermophilic serine protease from the halo-alkaliphilic Alkalibacillus sp. NM-Da2 was purified to homogeneity by ethanol precipitation and anion-exchange chromatography. The purified protease was a monomeric enzyme with an approximate molecular mass of 35 kDa and exhibited maximal activity at 2.7 M NaCl, pH55 °C 9 and 56 °C. The protease showed great temperature stability, retaining greater than 80 % of initial activity after 2 h incubation at 55 °C. The protease was also extremely pH tolerant, retaining 80 % of initial activity at pH55 °C 10.5 after 30 min incubation. Protease hydrolyzed complex substrates, displaying activity on yeast extract, tryptone, casein, gelatin and peptone. Protease activity was inhibited at casein concentrations greater than 1.2 mg/mL. The enzyme was stable and active in 40 % (v/v) solutions of isopropanol, ethanol and benzene and was stable in the presence of the polysorbate surfactant Tween 80. Activity was stimulated with the oxidizing agent hydrogen peroxide. Inhibition with phenyl methylsulfonylfluoride indicates it is a serine protease. Synthetic saline wastewater treated with the protease showed 50 % protein removal after 5 h. Being halophilic, alkaliphilic and thermophilic, in addition to being resistant to organic solvents, this protease has potential for various applications in biotechnological and pharmaceutical industries.  相似文献   

2.
In this study, a potent fibrinolytic enzyme-producing bacterium was isolated from soybean flour and identified as Bacillus subtilis K42 and assayed in vitro for its thrombolytic potential. The molecular weight of the purified enzyme was 20.5 kDa and purification increased its specific activity 390-fold with a recovery of 14%. Maximal activity was attained at a temperature of 40°C (stable up to 65°C) and pH of 9.4 (range: 6.5–10.5). The enzyme retained up to 80% of its original activity after pre-incubation for a month at 4°C with organic solvents such as diethyl ether (DE), toluene (TO), acetonitrile (AN), butanol (BU), ethyl acetate (EA), ethanol (ET), acetone (AC), methanol (ME), isopropanol (IP), diisopropyl fluorophosphate (DFP), tosyl-lysyl-chloromethylketose (TLCK), tosyl-phenylalanyl chloromethylketose (TPCK), phenylmethylsulfonylfluoride (PMSF) and soybean trypsin inhibitor (SBTI). Aprotinin had little effect on this activity. The presence of ethylene diaminetetraacetic acid (EDTA), a metal-chelating agent and two metallo protease inhibitors, 2,2′-bipyridine and o-phenanthroline, repressed the enzymatic activity significantly. This, however, could be restored by adding Co2+ to the medium. The clotting time of human blood serum in the presence of this enzyme reached a relative PTT of 241.7% with a 3.4-fold increase, suggesting that this enzyme could be an effective antithrombotic agent.  相似文献   

3.
Analysis of the Thermoplasma acidophilum DSM 1728 genome identified two putative alcohol dehydrogenase (ADH) open reading frames showing 50.4% identity against each other. The corresponding genes Ta0841 and Ta1316 encode proteins of 336 and 328 amino acids with molecular masses of 36.48 and 36.01 kDa, respectively. The genes were expressed in Escherichia coli and the recombinant enzymes were functionally assessed for activity. Throughout the study only Ta1316 ADH resulted active in the oxidative reaction in the pH range 2–8 (optimal pH 5.0) and temperatures from 25 to 90°C (optimal 75°C). This ADH catalyzes the oxidation of several alcohols such as ethanol, methanol, 2-propanol, butanol, and pentanol during the reduction of the cofactor NAD+. The highest activity was found in the presence of ethanol producing optically pure acetaldehyde. The specific enzyme activity of the purified Ta1316 ADH with ethanol as a substrate in the optimal conditions was 628.7 U/mg.  相似文献   

4.
An anionic trypsin (TRY-EP) was purified from North Pacific krill (Euphausia pacifica) by ammonium sulfate precipitation, ion-exchange and gel-filtration chromatography. The purified enzyme was identified as a trypsin by LC-ESI-MS/MS analysis. The relative molecular mass of TRY-EP was 33 kDa, with isoelectric point of 4.5. The histidine, tryptophan, arginine, lysine, aspartic acid and glutamic acid residues were functional groups to TRY-EP. TRY-EP was activated by Ca2+ and Mg2+ and inhibited by some heavy metal ions (Zn2+, Cu2+, Pb2+ and Hg2+), organic solvents (ethanol, glycerin, DMSO and acetone) and specific trypsin inhibitors (benzamidine, CEOM, SBTI and TLCK). TRY-EP was active over a wide pH (6.0–11.0) and temperature (10–70°C) range, with optimum of pH 9.0 and 40–50°C. TRY-EP was stable between pH 6.0 and 11.0 and below 30°C. Compared with some trypsins from the Temperate and Tropical Zone organisms, TRY-EP and other trypsins from the Frigid Zone organisms have higher affinity to substrate and 2–42-fold physiological efficiency.  相似文献   

5.
An extracellular thermostable alkaline protease isolated from Bacillus laterosporus-AK1 was purified by sephadex G-200 gel filtration and DEAE cellulose ion-exchange chromatography techniques. The purified protease showed a maximum relative activity of 100% on casein substrate and appeared as a single band on SDS-PAGE with the molecular mass of 86.29 kDa. The protease was purified to 11.1-folds with a yield of 34.3%. Gelatin zymogram also revealed a clear hydrolytic zone due to proteolytic activity, which corresponded to the band obtained with SDS-PAGE. The protease enzyme had on optimum pH of 9.0 and exhibited highest activity at 75°C. The enzyme activity was highly susceptible to the specific serine protease inhibitor PMSF, suggesting the presence of serine residues at the active sites. Enzyme activity strongly enhanced by the metal ions Ca2+ and Mg2+ and this enzyme compatible with aril detergent stability retained 75% even 1-h incubation. The purified protease remove bloodstain completely when used with Wheel detergent.  相似文献   

6.
The production of a protease was investigated under conditions of high salinity by the moderately halophilic bacterium Halobacillus karajensis strain MA-2 in a basal medium containing peptone, beef extract, maltose and NaCl when the culture reached the stationary growth phase. Effect of various temperatures, initial pH, salt and different nutrient sources on protease production revealed that the maximum secretion occurred at 34°C, pH 8.0–8.5, and in the presence of gelatin. Replacement of NaCl by various concentrations of sodium nitrate in the basal medium also increased the protease production. The secreted protease was purified 24-fold with 68% recovery by a simple approach including a combination of acetone precipitation and Q-Sepharose ion exchange chromatography. The enzyme revealed a monomeric structure with a relative molecular mass of 36 kDa by running on SDS-PAGE. Maximum caseinolytic activity of the enzyme was observed at 50°C, pH 9.0 and 0.5 M NaCl, although at higher salinities (up to 3 M) activity still remained. The maximum enzyme activity was obtained at a broad pH range of 8.0–10.0, with 55 and 50% activity remaining at pH 6 and 11, respectively. Moreover, the enzyme activity was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF), Pefabloc SC and EDTA; indicating that it probably belongs to the subclass of serine metalloproteases. These findings suggest that the protease secreted by Halobacillus karajensis has a potential for biotechnological applications from its haloalkaline properties point of view.  相似文献   

7.
Proteases are now recognized as the most indispensable industrial biocatalyst owing to their diverse microbial sources and innovative applications. In the present investigation, a thermostable, organic solvent-tolerant, alkaline serine protease from Bacillus circulans MTCC 7942, was purified and characterized. The protease was purified to 37-fold by a three-step purification scheme with 39% recovery. The optimum pH and temperature for protease was 10 and 60°C, respectively. The apparent molecular mass of the purified enzyme was 43 kD as revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The Km and Vmax values using casein-substrate were 3.1 mg/mL and 1.8 µmol/min, respectively. The protease remained stable in the presence of organic solvents with higher (>3.2) log P value (cyclohexane, n-octane, n-hexadecane, n-decane, and n-dodecane), as compared to organic solvents with lower (<3.2) log P value (acetone, butanol, benzene, chloroform, toluene). Remarkably, the protease showed profound stability even in the presence of organic solvents with less log P values (glycerol, dimethyl sulfate [DMSO], p-xylene), indicating the possibility of nonaqueous enzymatic applications. Also, protease activity was improved in the presence of metal ions (Ca2+, Mg2+, Mn2+); enhanced by biosurfactants; hardly affected by bleaching agents, oxidizing agents, and chemical surfactants; and stable in commercial detergents. In addition, a protease–detergent formulation effectively washed out egg and blood stains as compared to detergent alone. The protease was suitable for various commercial applications like processing of gelatinous film and as a compatible additive to detergent formulation with its operative utility in hard water.  相似文献   

8.
Synergistes sp. DQ560074 produced a protease in submerged fermentation (SmF) at 400–420 U/mL and in solid‐state fermentation (SSF) at 745–755 U/g. The protease, which belongs to the aspartic protease class, was active over a wide range of pH (5–7) and at high temperatures (25–45°C). The protease is stable and active in various polar protic solvents (50% v/v) like ethanol, isopropanol, n–butanol, in polar aprotic solvents (50% v/v) like acetonitrile, and in non‐polar solvents (50% v/v) such as ethylacetate and toluene, but not in hydrophilic organic solvents (methyl alcohol and acetone). As far as we know, this is the first contribution to the production of a mesophilic protease with solvent stability in SSF using a proteinaceous solid waste.  相似文献   

9.
Totally 191 different marine actinomycetes were isolated from 256 different marine samples collected from the Bay of Bengal and its associated Pulicat lake and Pichavaram mangrove, India. Among them, 157 produced caseinase, 113 produced gelatinase and 108 produced both the protease enzymes. An isolate coded as MML1614 was selected for further study as it exhibited high proteolytic activity. The MML1614 was identified as Streptomyces fungicidicus based on polyphasic taxonomical approach including 16S rRNA sequence analysis. The culture conditions were standardized for the growth and protease production in S. fungicidicus MML1614. The protease was isolated from a 6-day-old culture filtrate of S. fungicidicus MML1614 and partially purified up to 4.5-fold. The protease was optimally active at pH 9 and 40 °C and it was stable up to pH 11 and 60 °C. PMSF and NaCl inhibited the enzyme activity up to 22 and 11%, respectively. The partially purified protease removed the blood stain more effectively when combined with different detergents than the detergents alone.  相似文献   

10.
A study on the feasibility of using improved computer-controlled HPLC and GC systems was carried out to shorten the time needed for measuring levels of the substrates (glucose, maltose, and glycerol) and products (acetone, butanol ethanol, acetic acid, and butyric acid) produced byClostridium saccharobutylicum DSM 13864 during direct fermentation of sago starch to solvent. The use of HPLC system with a single injection to analyse the composition of culture broth (substrates and products) during solvent fermentation was achieved by raising the column temperature to 80°C. Although good separation of the components in the mixture was achieved, a slight overlap was observed in the peaks for butyric acid and acetone. The shape of the peak obtained and the analysis time of 26.66 min were satisfactory at a fixed flow rate of 0.8 mL/min. An improved GC system was developed, that was able to measure the products of solvent fermentation (acetone, butanol, ethanol, acetic acid, and butyric acid) within 19.28 min. Excellent resolution for each peak was achieved by adjusting the oven temperature to 65°C.  相似文献   

11.
12.
A bacterium that secretes maltooligosaccharide-forming amylase in a medium containing 12.5% (vol/vol) dimethylsulfoxide (DMSO) was isolated and identified as Brachybacterium sp. strain LB25. The amylase of the strain was purified from the culture supernatant, and its molecular mass was 60 kDa. The enzyme was stable at pH 7.0–8.5 and active at pH 6.0–7.5. The optimum temperature at pH 7.0 was 35°C in the presence of 5 mM CaCl2. The enzyme hydrolyzed starch to produce maltotriose primarily. The enzyme was active in the presence of various organic solvents. Its yield and product selectivity of maltooligosaccharides in the presence of DMSO or ethanol were compared with those of the industrial maltotriose-forming amylase from Microbacterium imperiale. Both enzymes improved the production selectivity of maltotriose by the addition of DMSO or ethanol. However, the total maltooligosaccharide yield in the presence of the solvents was higher for LB25 amylase than for M. imperiale amylase.  相似文献   

13.
A protease-producing bacterium was isolated from an alkaline wastewater of the soap industry and identified as Vibrio metschnikovii J1 on the basis of the 16S rRNA gene sequencing and biochemical properties. The strain was found to over-produce proteases when it was grown at 30°C in media containing casein as carbon source (14,000 U ml−1). J1 enzyme, the major protease produced by V. metschnikovii J1, was purified by a three-step procedure, with a 2.1-fold increase in specific activity and 33.3% recovery. The molecular weight of the purified protease was estimated to be 30 kDa by SDS-PAGE and gel filtration. The N-terminal amino acid sequence of the first 20 amino acids of the purified J1 protease was AQQTPYGIRMVQADQLSDVY. The enzyme was highly active over a wide range of pH from 9.0 to 12.0, with an optimum at pH 11.0. The optimum temperature for the purified enzyme was 60°C. The activity of the enzyme was totally lost in the presence of PMSF, suggesting that the purified enzyme is a serine protease. The kinetic constants K m and K cat of the purified enzyme using N-succinyl-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide were 0.158 mM and 1.14 × 105 min−1, respectively. The catalytic efficiency (K cat /K m) was 7.23 × 108 min−1 M−1. The enzyme showed extreme stability toward non-ionic surfactants and oxidizing agents. In addition, it showed high stability and compatibility with some commercial liquid and solid detergents. The aprJ1 gene, which encodes the alkaline protease from V. metschnikovii J1, was isolated, and its DNA sequence was determined. The deduced amino acid sequence of the preproenzyme differs from that of V. metschnikovii RH530 detergent-stable protease by 12 amino acids, 7 located in the propeptide and 5 in the mature enzyme.  相似文献   

14.
Fusarium sp. BLB, which produces a strongly fibrinolytic enzyme, was isolated from plant leaf (Hibiscus). Fibrinolytic alkaline protease was purified from a culture filtrate of Fusarium sp. BLB by precipitation with (NH4)2SO4 and column chromatography with CM-Toyopearl 650M and Superdex 75. The purified enzyme was homogeneous on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight was 27,000 by SDS-PAGE. Maximum activity of protease was observed at pH 9.5 and 50°C. Purified protease was active between pH 2.5 and 11.5 and was found to be stable up to 50°C. The enzyme derived from Fusarium sp. BLB is useful for thrombolytic therapy because this enzyme showed pH resistance. The activity was inhibited by diisopropylfluorophosphate and phenylmethylsulfonyl fluoride. The N-terminal amino acid sequence of the enzyme showed a similarity to those of proteases from Fusarium sp., Streptomyces griseus, Bos taurus bovine, Katsuwo pelamis digestive tract, and Lumbricus rubellus.  相似文献   

15.
Thermotoga hypogea is an extremely thermophilic anaerobic bacterium capable of growing at 90°C. It uses carbohydrates and peptides as carbon and energy sources to produce acetate, CO2, H2, l-alanine and ethanol as end products. Alcohol dehydrogenase activity was found to be present in the soluble fraction of T. hypogea. The alcohol dehydrogenase was purified to homogeneity, which appeared to be a homodimer with a subunit molecular mass of 40 ± 1 kDa revealed by SDS-PAGE analyses. A fully active enzyme contained iron of 1.02 ± 0.06 g-atoms/subunit. It was oxygen sensitive; however, loss of enzyme activity by exposure to oxygen could be recovered by incubation with dithiothreitol and Fe2+. The enzyme was thermostable with a half-life of about 10 h at 70°C, and its catalytic activity increased along with the rise of temperature up to 95°C. Optimal pH values for production and oxidation of alcohol were 8.0 and 11.0, respectively. The enzyme had a broad specificity to use primary alcohols and aldehydes as substrates. Apparent K m values for ethanol and 1-butanol were much higher than that of acetaldehyde and butyraldehyde. It was concluded that the physiological role of this enzyme is likely to catalyze the reduction of aldehydes to alcohols.  相似文献   

16.
A new high-alkaline protease (ALTP) was purified to homogeneity from a culture of the strictly anaerobic and extremely alkaliphilic Alkaliphilus transvaalensis. The molecular mass was 30 kDa on sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The enzyme showed the maximal caseinolytic activity higher than pH 12.6 in KCl–NaOH buffer at 40°C. Hydrolysis of the oxidized insulin B-chain followed by mass spectrometric analysis of the cleaved products revealed that as many as 24 of the total 29 peptide bonds are hydrolyzed in a block-cutting manner, suggesting that ALTP has a widespread proteolytic functions. Calcium ion had no effect on the activity and stability of ALTP, unlike known subtilisins. The deduced amino acid sequence of the enzyme comprised 279 amino acids plus 97 prepropeptide amino acids. The amino acid sequence of mature ALTP was confirmed by capillary liquid chromatography coupled to tandem mass spectrometry, which was the 93% coverage of the deduced amino acid sequence. The mature enzyme showed moderate homology to subtilisin LD1 from the alkaliphilic Bacillus sp. strain KSM-LD1 with 64% identity, and both enzymes formed a new subcluster at an intermediate position among true subtilisins and high-alkaline proteases in a phylogenetic tree of subtilase family A. ALTP is the first high-alkaline protease reported from a strict anaerobe in this family.  相似文献   

17.
44 species of the genus Clostridium were examined with regard to their ability to grow on citrate. In addition to Clostridium sphenoides, a known citrate utilizer, the following species were found to utilize citrate: C. sporosphaeroides, C. symbiosum, C. rectum, C. indolis, C. subterminale and C. sporogenes. The major products formed from citrate were acetate, ethanol and carbon dioxide (not measured). Minor products were butyrate, butanol, acetone and acetoin.The enzyme citrate lyase was detectable in cell extracts of C. sporosphaeroides and C. symbiosum using an optical assay. Evidence for the presence of this enzyme in the other species was obtained in immunological experiments and in experiments with [1,5-14C]citrate.  相似文献   

18.
The purification and characterization of psychro‐thermoalkalistable protease from psychrotrophic Pseudomonas putida isolate is being reported for the first time. A ~53 kDa protease was purified 21.4‐folds with 57.2% recovery by ultrafiltration and hydrophobic interaction chromatography. Kinetic analyses revealed the Km and Vmax to be 1.169 mg mL?1 and 0.833 mg mL?1 min?1, respectively. The kcat value of 3.05 × 102 s?1 indicated high affinity and catalytic efficiency toward casein. The protease was most active at pH 9.5 and 40°C, with 100% stability in pH and temperature range of 6.0–11.0 and 10–40°C, respectively. Presence of Zn2+ increased the thermostability of protease (at 70°C) by 433%. Ethylene diamine tetra acetic acid (EDTA) and 1,10‐phenanthroline were inhibitory, whereas phenyl methyl sulfonyl fluoride (PMSF), p‐chloro mercuric benzoate (PCMB), and β‐mercaptoethanol were ineffective, revealing the enzyme to be a metalloprotease. Zinc, calcium, iron, nickel, and copper at 1 mM increased the enzyme activity (102–134%). Complete reversion of enzyme inhibition (caused by Ethylene diamine tetra acetic acid [EDTA]) by Zn2+ affirmed this enzyme as zinc‐dependent metalloprotease. At 0.1% concentration, Triton X‐100 and Tween 80 slightly increased, while SDS and H2O2 reduced the protease activity. In the presence of 0.1% commercial detergents, the enzyme was fairly stable (54–81%). In the presence of organic solvent, the protease was remarkably stable exhibiting 72–191% activities. In contrast, savinase exhibited good stability in the presence of hydrophilic solvents, while chymotrypsin showed elevated activities with benzene, toluene, and xylene only. Circular dichroism analysis revealed the protease as a β‐rich protein, having large fraction (~40%) of β‐sheets. Presence of different environmental conditions altered the β‐content, which accordingly affected the protease activity. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013  相似文献   

19.
The present study was designed to isolate and identify an extremely halophilic lipase-producing bacterial strain, purify and characterize the related enzyme and evaluate its application for ethyl and methyl valerate synthesis. Among four halophilic isolates, the lipolytic ability of one isolate (identified as Bacillus atrophaeus FSHM2) was confirmed. The enzyme (designated as BaL) was purified using three sequential steps of ethanol precipitation and dialysis, Q-Sepharose XL anion-exchange chromatography and SP Sepharose cation-exchange chromatography with a final yield of 9.9% and a purification factor of 31.8. The purified BaL (Mw~85?kDa) was most active at 70?°C and pH 9 in the presence of 4 M NaCl and retained 58.7% of its initial activity after 150?min of incubation at 80?°C. The enzyme was inhibited by Cd2+ (35.6?±?1.7%) but activated by Ca2+ (132.4?±?2.2%). Evaluation of BaL's stability in the presence of organic solvents showed that xylene (25%) enhanced the relative activity of the enzyme to 334.2?±?0.6% after 1?h of incubation. The results of esterification studies using the purified BaL revealed that maximum ethyl valerate (88.5%) and methyl valerate (67.5%) synthesis occurred in the organic solvent medium (xylene) after 48?h of incubation at 50?°C.  相似文献   

20.
In this communication, we report the presence of a newly identified serine alkaline protease producing bacteria, Virgibacillus pantothenticus (MTCC 6729) in the fresh chicken meat samples and the factors affecting biosynthesis as well as characterization of protease. The strain produced only 14.3 U ml−1 protease in the standard medium after 72 h of incubation, while in optimized culture conditions the production of protease was increased up to 18.2 U ml−1. The strain was able to produce protease at 40°C at pH 9.0. The addition of dextrose and casein improved protease production. The protease was partially purified and characterized in terms of pH and temperature stability, effect of metal ions and inhibitors. The protease was found to be thermostable alkaline by retaining its 100% and 85% stability at pH 10.0 and at 50°C respectively. The protease was compatible with some of the commercial detergents tested, and was effective in removing protein stains from cotton fabrics. The V. pantothenticus, MTCC 6729 protease appears to be potentially useful as an additive in detergents as a stain remover and other bio-formulations.  相似文献   

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