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1.
Ali Nel-H Hmidet N Ghorbel-Bellaaj O Fakhfakh-Zouari N Bougatef A Nasri M 《Applied biochemistry and biotechnology》2011,164(7):1096-1110
Alkaline proteases from the viscera of the striped seabream (Lithognathus mormyrus) were extracted and characterized. Interestingly, the crude enzyme was active over a wide range of pH from 6.0 to 11.0, with
an optimum pH at the range of 8.0–10.0. In addition, the crude protease was stable over a broad pH range (5.0–12.0). The optimum
temperature for enzyme activity was 50 °C. The crude alkaline proteases showed stability towards various surfactants and bleach
agents and compatibility with some commercial detergents. It was stable towards several organic solvents and retained more
than 50% of its original activity after 30 days of incubation at 30 °C in the presence of 25% (v/v) dimethyl sulfoxide, N,N-dimethylformamide, diethyl ether, and hexane. The crude enzyme extract was also tested for shrimp waste deproteinization
in the preparation of chitin. The protein removal with a ratio enzyme/substrate of 10 was about 79%. 相似文献
2.
Laila Manni Kemel Jellouli Olfa Ghorbel-Bellaaj Rym Agrebi Anissa Haddar Alya Sellami-Kamoun Moncef Nasri 《Applied biochemistry and biotechnology》2010,160(8):2308-2321
The current increase in amount of shrimp wastes produced by the shrimp industry has led to the need in finding new methods
for shrimp wastes disposal. In this study, an extracellular organic solvent- and oxidant-stable metalloprotease was produced
by Bacillus cereus SV1. Maximum protease activity (5,900 U/mL) was obtained when the strain was grown in medium containing 40 g/L shrimp wastes
powder as a sole carbon source. The optimum pH, optimum temperature, pH stability, and thermal stability of the crude enzyme
preparation were pH 8.0, 60 °C, pH 6–9.5, and <55 °C, respectively. The crude protease was extremely stable toward several
organic solvents. No loss of activity was observed even after 60 days of incubation at 30 °C in the presence of 50% (v/v) dimethyl sulfoxide and ethyl ether; the enzyme retained more than 70% of its original activity in the presence of ethanol
and N,N-dimethylformamide. The protease showed high stability toward anionic (SDS) and non-ionic (Tween 80, Tween 20, and Triton
X-100) surfactants. Interestingly, the activity of the enzyme was significantly enhanced by oxidizing agents. In addition,
the enzyme showed excellent compatibility with some commercial liquid detergents. The protease of B. cereus SV1, produced under the optimal culture conditions, was tested for shrimp waste deproteinization in the preparation of chitin.
The protein removal with a ratio E/S of 20 was about 88%. The novelties of the SV1 protease include its high stability to organic solvents and surfactants. These
unique properties make it an ideal choice for application in detergent formulations and enzymatic peptide synthesis. In addition,
the enzyme may find potential applications in the deproteinization of shrimp wastes to produce chitin. 相似文献
3.
Rym Agrebi Noomen Hmidet Mohamed Hajji Nawrez Ktari Anissa Haddar Nahed Fakhfakh-Zouari Moncef Nasri 《Applied biochemistry and biotechnology》2010,162(1):75-88
In this study, Mirabilis jalapa tuber powder (MJTP) was used as a new complex organic substrate for the growth and production of fibrinolytic enzymes by
a newly isolated Bacillus amyloliquefaciens An6. Maximum protease activity (1,057 U/ml) with casein as a substrate was obtained when the strain was grown in medium containing
(grams per liter) MJTP 30, yeast extract 6, CaCl2 1, K2HPO4 0.1, and K2HPO4 0.1. The strain was also found to grow and produce extracellular proteases in a medium containing only MJTP, indicating that
it can obtain its carbon, nitrogen, and salts requirements directly from MJTP. The B. amyloliquefaciens An6 fibrinase (BAF1) was partially purified, and fibrinolytic activity was assayed in a test tube with an artificial fibrin
clot. The molecular weight of the partially purified BAF1 fibrinolytic protease was estimated to be 30 kDa by sodium dodecyl
sulfate polyacrylamide gel electrophoresis and gel filtration. The optimum temperature and pH for the caseinolytic activity
were 60 °C and 9.0, respectively. The enzyme was highly stable from pH 6.0 to 11.0 and retained 62% of its initial activity
after 1 h incubation at 50 °C. However, the enzyme was inactivated at higher temperatures. The activity of the enzyme was
totally lost in the presence of phenylmethylsulfonyl fluoride, suggesting that BAF1 is a serine protease. 相似文献
4.
Xiao-Yu Tang Bin Wu Han-Jie Ying Bing-Fang He 《Applied biochemistry and biotechnology》2010,160(4):1017-1031
An organic solvent-stable protease from Pseudomonas aeruginosa PT121 was purified in a single step with 55% recovery by hydrophobic interaction chromatography on a Phenyl Sepharose High
Performance matrix. The purified protease was homogenous on SDS-PAGE and had an estimated molecular mass of 33 kDa. The optimal
pH and temperature conditions for enzyme activity were 8.0 and 60°C, respectively. The enzyme was classified as a metalloprotease
based on its strong inhibition by EDTA and 1,10-phenanthroline and exhibited good stability across a broad pH range (6.0–11.0).
The protease was quite stable in the presence of various water-miscible organic solvents. This is a unique property of the
protease which makes it an ideal choice for application in aqueous-organic phase organic synthesis including peptides synthesis.
The synthetic activity of the protease was tested using N-carbobenzoxy-l-asparagine (Z-Asp) and l-phenylalaninamide (Phe-NH2) as substrate in the presence of various water-miscible organic solvents for aspartame precursor synthesis. The highest yield
was obtained in the presence of 50% DMSO (91%). The synthesis rate in the presence of DMSO was also much higher than the rates
in the other tested organic solvents, and the initial rates of Z-Asp-Phe-NH2 synthesis in mixtures of various water-miscible organic solvents, with the exception of ethanol, correlated with the yields
of Z-Asp-Phe-NH2. Furthermore, the PT121 protease was able to use various carboxyl components (Z-AA) and Phe-NH2 as substrates to catalyze the syntheses of the dipeptides, indicating that this protease has a broad specificity for carboxylic
acid residue. 相似文献
5.
Ali A. El‐Bardan Gehan M. El‐Subruiti Fatma El‐Zahraa M. El‐Hegazy Ezzat A. Hamed 《国际化学动力学杂志》2002,34(11):645-650
The kinetics of the reaction of substituted anilines with 2‐chloro‐5‐nitropyridine were studied in dimethyl sulfonide (DMSO) and dimethyl formamide (DMF) at different amine concentrations and temperatures in the range 45–60°C. In both solvents the reaction was not a base‐catalyzed one. A plot of ΔH# versus ΔS# for the reaction in DMSO and DMF gave good straight lines with isokinetic temperatures 128°C and 105°C, respectively. Good linear relationships were obtained from the plots of log k1 against σ° values at all temperatures with negative ρ values (?1.63 to ?1.28 in DMSO) and (?1.26 to ?0.90 in DMF). © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 645–650, 2002 相似文献
6.
Renganathan Jayakumar Shanmugam Jayashree Balumuri Annapurna Sundaram Seshadri 《Applied biochemistry and biotechnology》2012,168(7):1849-1866
This study describes the characterization and optimization of medium components for an extracellular detergent, surfactant, organic solvent and thermostable serine alkaline protease produced by alkaliphilic Bacillus pumilus MCAS8 strain isolated from Pulicat lake sediments, Tamil Nadu, India. The strain yielded maximum protease (2,214?U/ml) under optimized conditions: carbon source, citric acid??1.5?% (w/w); inducer, soyabean meal??2?% (w/w); pH?11.0; shaking condition 37?°C for 48?h. The enzyme had pH and temperature optima of 9.0 and 60?°C, respectively. The enzyme displayed the molecular mass of 36?kDa in sodium dodecyl sulphate?Cpolyacrylamide gel electrophoresis study and exhibited activity at a wide range of pH (6.0?C11.0) and thermostability (20?C70?°C). More than 70?% residual activity was observed when the enzyme was incubated with dithiothreitol, ethylenediaminetetraacetic acid, ethylene glycol tetraacetic acid and H2O2 for 30?min. The protease activity was also enhanced by divalent cations such as Ba2+, Ca2+ and Mg2+ and was strongly inhibited by Fe2+, Zn2+, Sr2+, Hg2+ and urea. The enzyme retained more than 50?% of its initial activity after pre-incubation for 1?h in the presence of 5?% (v/v) organic solvents such as dimethyl sulphoxide and acetone. The protease could hydrolyse various native proteinaceous substrates (1?%?w/v) such as bovine serum albumin, casein, skim milk, gelatine, azocasein and haemoglobin. Wash performance analysis of enzyme revealed that it could effectively remove blood stains from the cotton fabric, thus making it suitable to use as an effective detergent additive. The protease enzyme also exhibited promising result in the dehairing of goat skin. The potency of the eco-friendly enzyme without using any chemicals against washing and dehairing showed that the enzyme could be used for various industrial applications. 相似文献
7.
A haloalkaliphilic bacterium was isolated from salt-enriched soil of Mithapur, Gujarat (India) and identified as Bacillus agaradhaerens Mi-10-62 based on 16S rRNA sequence analysis (NCBI gene bank accession, GQ121032). The bacterium was studied for its α-amylase characteristic
in the presence of organic solvents. The enzyme was quite active and it retained considerable activity in 30% (v/v) organic solvents, dodecane, decane, heptane, n-hexane, methanol, and propanol. At lower concentrations of solvents, the catalysis was quite comparable to control. Enzyme
catalysis at wide range of alkanes and alcohol was an interesting finding of the study. Mi-10-62 amylase retained activity over a broader alkaline pH range, with the optimal pH at 10–11. Two molars of salt was optimum
for catalysis in the presence of most of the tested solvents, though the enzyme retained significant activity even at 4 M
salt. With dodecane, the optimum temperature shifted from 50 °C to 60 °C, while the enzyme was active up to 80 °C. Over all,
the present study focused on the effect of organic solvents on an extracellular α-amylase from haloalkaliphilic bacteria under
varying conditions of pH, temperature, and salt. 相似文献
8.
J Deepa Arul Priya K Divakar M Suryia Prabha G Panneer Selvam Pennathur Gautam 《Applied biochemistry and biotechnology》2014,172(2):910-932
A new organic solvent-tolerant strain Bacillus megaterium AU02 which secretes an organic solvent-tolerant protease was isolated from milk industry waste. Statistical methods were employed to achieve optimum protease production of 43.6 U/ml in shake flask cultures. The productivity of the protease was increased to 53 U/ml when cultivated under controlled conditions in a 7-L fermentor. The protease was purified to homogeneity by a three-step process with 24 % yield and specific activity of 5,375 U/mg. The molecular mass of the protease was found to be 59 kDa. The enzyme was active over a wide range of pH (6.0–9.0), with an optimum activity at pH 7.0 and temperature from 40 to 70 °C having an optimum activity at 50 °C. The thermal stability of the enzyme increased significantly in the presence of CaCl2, and it retained 90 % activity at 50 °C for 3 h. The K m and V max values were determined as 0.722 mg/ml and 0.018 U/mg respectively. The metalloprotease exhibited significant stability in the presence of organic solvents with log P values more than 2.5, nonionic detergents and oxidising agent. An attempt was made to test the synthesis of aspartame precursor (Cbz-Asp-Phe-NH2) which was catalysed by AU02 protease in the presence of 50 % DMSO. These properties of AU02 protease make it an ideal choice for enzymatic peptide synthesis in organic media. 相似文献
9.
K. K. Spektor G. L. Starova Yu. M. Skripkin L. V. Stepakova 《Russian Journal of General Chemistry》2011,81(9):1772-1777
Structures of copper dihalide solvates with dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) were determined by XRD single crystal analysis. The existence of two DMSO solvates with CuBr2, but only one with CuCl2, was attributed to a lower Cu-Br bond strength in comparison with Cu-Cl, and, as a consequence, by its easier breaking to
form a bond with a solvent molecule. Fundamentally different structures of CuX2·2DMF (X = Br, Cl) solvates are caused by different donor power of the acido ligands. 相似文献
10.
Eltayib Hassan Ahmed Tripti Raghavendra Datta Madamwar 《Applied biochemistry and biotechnology》2010,160(7):2102-2113
A mesophilic bacterial culture producing a novel thermostable alkaline lipase was isolated from oil rich soil sample and identified
as Bacillus subtilis EH 37. The lipase was partially purified by ammonium sulfate precipitation and hydrophobic interaction chromatography with
17.8-fold purification and 41.9 U/ml specific activity. The partially purified enzyme exhibited maximum activity at pH 8.0
and at 60 °C. It retained 100% of activity at 50 °C and 60 °C for 60 min. The presence of Ca+2, Mg+2, and Zn2+ exhibited stimulatory effect on lipase activity, whereas Fe+3 and Co+2 reduced its activity. The enzyme retained more than 80% of its initial activity upon exposure to organic solvents, exhibited
107% and 115% activity in the presence of 15% isopropyl alcohol and 30% n-hexane, respectively. The EH 37 lipase also proved
to be an efficient catalyst in synthesis of ethyl caprylate in organic solvent, thus providing a concept of application of
B. subtilis lipase in non-aqueous catalysis. 相似文献
11.
Min-Yuan Wan Hai-Yan Wang Yi-Zheng Zhang Hong Feng 《Applied biochemistry and biotechnology》2009,159(2):394-403
An alkaline protease (DHAP) from Bacillus pumilus has shown great potential in hide dehairing. To get better insights on its catalytic properties for application, the substrate
specificity and thermostability were investigated using five natural proteins and nine synthetic peptides. The results showed
that DHAP could hydrolyze five proteins tested here in different specificity. Collagen, a component of animal skin, was more
resistant to hydrolysis than casein, fibrin, and gelatin. Among the synthetic peptides, the enzyme showed activity mainly
with tetrapeptide substrates with the catalytic efficiency in order of Phe>Leu>Ala at P1 site, although k
m value for AAVA-pN is much lower than that for AAPL-pN and AAPF-pN. With tripeptide substrates, smaller side-chain group (Gly)
at P1 site was not hydrolyzed by DHAP. The enzyme showed good thermostability below 60 °C, and lost activity so quickly above
70 °C. The thermostability was largely dependent on metal ion, especially Ca2+, although other ions, like Mg2+, Mn2+, and Co2+, could sustain stability at certain extent within limited time. Cu2+, Fe2+, as well as Al3+, did not support the enzyme to retain activity at 60 °C even in 5 min. In addition, the selected metal ions could coordinate
calcium in improvement or destruction of thermostability for DHAP. 相似文献
12.
Qi Wu Chen Li Chenglei Li Hui Chen Liu Shuliang 《Applied biochemistry and biotechnology》2010,160(1):129-139
The collagenase, produced extracellular by Bacillus pumilus Col-J, was purified by ammonium sulfate precipitation followed by two gel filtrations, involving Sephadex G-100 column and
Sepharose Fast Flow column. Purified collagenase has a 31.53-fold increase in specific activity of 87.33 U/mg and 7.00% recovery.
The collagenase has a relative molecular weight of 58.64 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
The optimal temperature for the enzyme reaction was 45 °C. More than 50% of the original activity still remained after 5 min
of incubation at 70 °C or 10 min at 60 °C. The maximal enzyme activity of collagenase was obtained at pH 7.5, and it was stable
over a pH range of 6.5–8.0. The collagenase activity was strongly inhibited by Mn2+, Pb2+, ethylenediamine tetraacetic acid, ethylene glycol tetraacetic acid, and β-mercaptoethanol. However, Ca2+ and Mg2+ greatly increased its activity. The collagenase from B. pumilus Col-J showed highly specific activity towards the native collagen from calf skin. The K
m and V
max of the enzyme for collagen were 0.79 mg/mL and 129.5 U, respectively. 相似文献
13.
Hamid Reza Karbalaei-Heidari Mahnaz Shahbazi Ghodratollah Absalan 《Applied biochemistry and biotechnology》2013,170(3):573-586
An extracellular protease was purified from a novel moderately halophilic bacterium Salinivibrio sp. strain MS-7 by the combination of an acetone precipitation (40–80 %) step and a DEAE-cellulose anion exchange column chromatography. Kinetic parameters of the enzyme exhibited V max and K m of 130 U/mg and 1.14 mg/ml, respectively, using casein as a substrate. The biochemical properties of the enzyme revealed that the 21-kDa protease had a temperature and pH optimum of 50 °C and 8.0, respectively. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride, Pefabloc SC, chymostatin, and also EDTA, indicating that it belongs to the class of serine metalloproteases. Interestingly, Ba2+ and Ca2+ (2 mM) strongly enhanced the enzyme activity, while Fe2+ and Mg2+ activated moderately and Zn2+, Ni2+, and Hg2+ decreased the enzyme activity. The effect of organic solvents with different logP on the purified protease revealed complete stability in toluene, ethyl acetate, chloroform, and n-hexane at 10 and 50 % (v/v) and moderate stability even in 50 % of DMSO and ethanol. The behavior of the MS-7 protease in three imidazolium-based ionic liquids exhibited suitable activity in these green solvent systems, especially in 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]). Comparison of the purified protease with other previously reported proteases suggests that strain MS-7 secrets a novel organic solvent-tolerant protease with outstanding activity in organic solvents and imidazolium-based ionic liquids, which could be applied in low water synthetic section of industrial biotechnology. 相似文献
14.
New Thermostable Amylase from <Emphasis Type="Italic">Bacillus cohnii</Emphasis> US147 with a Broad pH Applicability 总被引:1,自引:0,他引:1
Ghorbel RE Maktouf S Massoud EB Bejar S Chaabouni SE 《Applied biochemistry and biotechnology》2009,157(1):50-60
A new thermophilic bacterial strain identified as Bacillus cohnii US147 was isolated from the southern Tunisian soil. The identification was based on physiological tests and molecular techniques
related to the 16S ribosomal ribonucleic acid. The isolated strain produced amylase, which was purified. This amylase had
an apparent molecular mass of 30 kDa as estimated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Amylase
US147 showed K
m and V
max values of 0.7 mg/ml and 2.2 U/ml, respectively, with starch as the substrate. The enzyme was active in acid and basic pH
and had a maximal activity on starch at pH 9 and 70 °C. The enzyme was stable at pH 9 for 72 h and retained half of its activity
after incubation at 70 °C for 150 min. A partially inhibition (15%, 25%, 23%, 20%, and 22%) was obtained with 1 mM SDS, 1 mM
NaBO3, 1 mM H2O2, 1 mM Zn+2, and 5 mM ethylenediamine tetraacetic acid (EDTA), respectively. The amylase recovered its original activity by the addition
of 10 mM Ca 2+ to the 5 mM EDTA. These properties indicated a possible use of this amylase in starch saccharification, in detergent, and
in other industrial applications. 相似文献
15.
Shu ZY Wu JG Cheng LX Chen D Jiang YM Li X Huang JZ 《Applied biochemistry and biotechnology》2012,166(3):536-548
The thermostable and organic solvent tolerant whole-cell lipase (WCL) was produced by Burkholderia sp. ZYB002 with broad spectrum organic solvent tolerance. The production medium of the WCL was primarily optimized, which
resulted in the maximum activity of 22.8 U/mL and the 5.1-fold increase of the WCL yield. The optimized culture medium was
as follows (% w/v or v/v): soybean meal 2, soybean oil 0.5, manganese sulfate 0.1, K2HPO4 0.1, olive oil 0.5, initial pH 6.0, inoculum density 2, liquid volume 35 mL in 250-mL Erlenmeyer flask, and incubation time
24 h. The biochemical characterization of the WCL from Burkholderia sp. ZYB002 was determined, and the results showed that the optimal pH and temperature for lipolytic activity of the WCL was
8.0 and 65°C, respectively. The WCL was stable at temperature up to 70°C for 1 h and retained 79.2% of its original activity.
The WCL was highly stable in the pH range from 3.0 to 8.5 for 6 h. Ca2+, K+, Na+, NO3−, etc. ions stimulated its lipolytic activity, whereas Zn2+ ion caused inhibition effect. The WCL was also relatively stable in n-butanol at a final concentration of 50% (v/v) for 24 h. However, the WCL was strongly inhibited in Triton X-100 at a final concentration of 10% (v/v). The WCL with thermal resistance and organic solvent tolerance showed its great potential in various green industrial chemical
processes. 相似文献
16.
Daniela de Araújo Viana Carolina de Albuquerque Lima Rejane Pereira Neves Cristina Souza Mota Keila Aparecida Moreira José Luiz de Lima-Filho Maria Taciana Holanda Cavalcanti Attilio Converti Ana Lúcia Figueiredo Porto 《Applied biochemistry and biotechnology》2010,162(3):830-842
Cow raw milk from dairy cooperatives was examined for its microbial composition. Among the isolates identified, 17.6% were
yeasts. The most frequent genus was Candida, although members belonging to the genera Brettanomyces, Dekkera, and Geotricum were also identified. Although qualitative and quantitative tests for extracellular proteolytic activity were positive for
all the species isolated, Candida buinensis showed the highest response (23.5 U/mg); therefore, it was selected for subsequent investigation. The results of fermentations
carried out at variable temperature, pH, and soybean flour concentration, according to a 23 full factorial design, demonstrated that this yeast ensured the highest production of extracellular proteases (573 U/mL)
when cultivated at 35 °C, pH 6.5, and using soybean flour concentrations in the range 0.1–0.5% (w/v). The cell-free supernatants showed the highest activity at 25 °C and pH 7.0, and satisfactory stability in the ranges 25–30 °C
and pH 7–9. The first-order rate constants of protease inactivation in the cell-free supernatants were calculated at different
temperatures from semi-log plots of the residual activity versus time and then used in Arrhenius and Eyring plots to estimate
the main thermodynamic parameters of thermoinactivation (E* = 40.0 kJ/mol; ΔH* = 37.3 kJ/mol; ΔS* = −197.5 J/mol K; ΔG* = 101 kJ/mol). 相似文献
17.
Moradian F Khajeh K Naderi-Manesh H Ahmadvand R Sajedi RH Sadeghizadeh M 《Applied biochemistry and biotechnology》2006,134(1):77-87
Two Bacillus sp. strains, HR-08 and KR-8102, isolated from soil of the west and north parts of Iran were screened on gelatin agar medium
for their ability to produce alkaline protease. The enzymes were active in a wide pH range (6.0–11.0) and stable in the alkaline
range (7.0–12.0). The optimum temperatures for the protease from HR-08 and KR-8102 were 65 and 50°C, respectively. The irreversible
thermoinactivation of HR-08 and KR-8102 proteases showed that the stability of HR-08 enzyme was higher than that of KR-8102
and the half-lives of these enzymes were 95 and 32 min at 50°C, respectively. In the presence of 10 mM Ca2+, HR-08 retained 100, 90, and 20% of its initial activity after heating for 30 min at 50, 60, and 70°C, respectively. Enzymes
were inhibited by phenylmethylsulfonyl fluoride and iodoacetate. After inhibition by iodoacetate, both enzymes were reactivated
by dithiothreitol. These data show that the enzymes seem to be thiol-dependent serine alkaline proteases. The enzymes especially
from HR-08 were stable in the presence of H2O2, surfactants, and local detergents; their activities were enhanced in the presence of 5 mM Fe2+; and the presence of 5mM metal ions such as Mg2+, Cu2+, and Mn2+ produced almost no effect. 相似文献
18.
Lokendra Kumar Balvinder Singh Dilip Kumar Adhikari Joydeep Mukherjee Debashish Ghosh 《Applied biochemistry and biotechnology》2012,166(7):1723-1735
Purification and characterization of halotolerant, thermostable alkaline l-glutaminase from a Bacillus sp. LKG-01 (MTCC 10401), isolated from Gangotri region of Uttarakhand Himalaya, is being reported in this paper. Enzyme has
been purified 49-fold from cell-free extract with 25% recovery (specific activity 584.2 U/mg protein) by (NH4)2SO4 precipitation followed by anion exchange chromatography and gel filtration. Enzyme has a molecular weight of 66 kDa. l-Glutaminase is most active at pH 11.0 and stable in the pH range 8.0–11.0. Temperature optimum is 70 °C and is completely
stable after 3 h pre-incubation at 50 °C. Enzyme reflects more enhanced activity with 1–20% (w/v) NaCl, which is further reduced to 80% when NaCl concentration was increased up to 25%. l-Glutaminase is almost active with K+, Zn2+, and Ni2+ ions and K
m and V
max values of 240 μM and 277.77 ± 1.1 U/mg proteins, respectively. Higher specific activity, purification fold, better halo-tolerance,
and thermostability would make this enzyme more attractive for food fermentation with respect to other soil microbe derived
l-glutaminase reported so far. 相似文献
19.
A bacterial strain isolated from spoiled coconut and identified as Bacillus cereus was found capable of producing alkaline thermostable extracellular lipase. Optimum temperature, time, and pH for enzyme substrate
reaction were found to be 60 °C, 10 min, and 8.0 respectively. Common surfactants except Triton X 100 and cetyltrimethylammonium
bromide have no or very little inhibitory effects on enzyme activity. The enzyme was found to be stable in presence of oxidizing
agents and protease enzyme. The maximum lipase production was achieved at 30–33 °C, pH 8.0 on 24 h of fermentation using 50 ml
medium in a 250-ml Erlenmeyer flask. The superior carbon and nitrogen sources for lipase production were starch (2%) and ammonium
sulfate (nitrogen level 21.2 mg/100 ml), peptone (nitrogen level 297 mg/100 ml), and urea (nitrogen level 46.62 mg/100 ml)
in combination, respectively. The maximum enzyme activity obtained was 33 ± 0.567 IU/ml. 相似文献
20.
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