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1.
The gene encoding a cold-adapted, organic solvent stable lipase from a local soil-isolate, mesophilic Staphylococcus epidermidis AT2 was expressed in a prokaryotic system. A two-step purification of AT2 lipase was achieved using butyl sepharose and DEAE sepharose column chromatography. The final recovery and purification fold were 47.09 % and 3.45, respectively. The molecular mass of the purified lipase was estimated to be 43 kDa. AT2 lipase was found to be optimally active at pH 8 and stable at pH 6–9. Interestingly, this enzyme demonstrated remarkable stability at cold temperature (<30 °C) and exhibited optimal activity at a temperature of 25 °C. A significant enhancement of the lipolytic activity was observed in the presence of Ca2+, Tween 60 and Tween 80. Phenylmethylsulfonylfluoride, a well known serine inhibitor did not cause complete inhibition of the enzymatic activity. AT2 lipase exhibited excellent preferences towards long chain triglycerides and natural oils. The lipolytic activity was stimulated by dimethylsulfoxide and diethyl ether, while more than 50 % of its activity was retained in methanol, ethanol, acetone, toluene, and n-hexane. Taken together, AT2 lipase revealed highly attractive biochemical properties especially because of its stability at low temperature and in organic solvents.  相似文献   

2.
Psychrotropic Bacillus sphaericus producing solvent stable cold-active lipase upon growth at low temperature was isolated from Gangotri glacier. Optimal parameters for lipase production were investigated and the strain was able to produce lipase even at 15 °C. An incubation period of 48 h and pH 8 was found to be conducive for cold-active lipase production. The addition of trybutyrin as substrate and lactose as additional carbon source increased lipase production. The enzyme was purified up to 17.74-fold by ammonium sulphate precipitation followed by DEAE cellulose column chromatography. The optimum temperature and pH for lipase activity were found to be 15 °C and 8.0, respectively. The lipase was found to be stable in the temperature range 20–30 °C and the pH range 6.0–9.0. The protein retained more than 83 % of its initial activity after exposure to organic solvents. The lipase exhibited significant stability in presence of acetone and DMSO retaining >90 % activity. The enzyme activity was inhibited by 10 mM CuSO4 and EDTA but showed no loss in activity after incubation with other metals or inhibitors examined in this study.  相似文献   

3.
A halophilic strain W33 showing lipolytic activity was isolated from the saline soil of Yuncheng Salt Lake, China. Biochemical and physiological characterization along with 16S rRNA gene sequence analysis placed the isolate in the genus Idiomarina. The extracellular lipase was purified to homogeneity by 75 % ammonium sulphate precipitation, DEAE-Sepharose anion exchange and Sephacryl S-200 gel filtration chromatography. The molecular mass of the purified lipase was estimated to be 67 kDa by SDS-PAGE. Substrate specificity test indicated that it preferred long-chain p-nitrophenyl esters. Optimal lipase activity was found to be at 60 °C, pH 7.0–9.0 and 10 % NaCl, and it was highly active and stable over broad temperature (30–90 °C), pH (7.0–11.0) and NaCl concentration (0–25 %) ranges, showing excellent thermostable, alkali-stable and halotolerant properties. Significant inhibition by diethyl pyrocarbonate and phenylarsine oxide was observed, implying histidine and cysteine residues were essential for enzyme catalysis. In addition, the lipase displayed high stability and activity in the presence of hydrophobic organic solvents with log P ow ≥ 2.13. The free and immobilized lipases produced by Idiomarina sp. W33 were applied for biodiesel production using Jatropha oil, and about 84 and 91 % of yields were achieved, respectively. This study formed the basic trials conducted to test the feasibility of using lipases from halophile for biodiesel production.  相似文献   

4.
A thermo-alkaliphilic lipase from Bacillus subtilis DR8806 was functionally expressed as an N-terminal 6xHis-tagged recombinant enzyme in Escherichia coli BL21 using pET-28a(+) expression vector. Sequence analysis revealed an open reading frame of 639 bp encoding a 212-amino acid protein containing the well-conserved Ala-His-Ser-Met-Gly motif. One-step purification of the His-tagged recombinant lipase was achieved using Ni-NTA affinity chromatography with a specific activity of 1364 U/mg. The purified enzyme with an apparent molecular mass of 26.8 kDa demonstrated the maximum activity at 70 °C and pH 8.0 for hydrolysis of p-nitrophenylbutyrate as substrate. The enzyme activity was strongly inhibited by divalent ions of heavy metals such as Hg2+ and Cu2+, while retained over 90% of the original activity in the presence of several reagents including DTNB (5,5′-dithiobis-(2-nitrobenzoic acid)), SDS (sodium dodecyl sulfate), urea, DMF (dimethylformamide), DTT (dithiothreitol), glycerol and Triton X-100. While being considerably stable in organic solvents, imidazolium-based ionic liquids (ILs) had stimulatory effects on the activity of purified lipase. Remarkable stabilization of enzyme at alkaline pH and in ionic liquids as well as its thermostability/thermoactivity are among the most fundamental characteristics which offer great potential for various biotechnological applications including detergent formulation, bioremediation processes and biotransformation in non-aqueous media.  相似文献   

5.
A novel lipase gene from an organic solvent degradable strain Pseudomonas fluorescens JCM5963 was cloned, sequenced, and overexpressed as an N-terminus His-tag fusion protein in E. coli. The alignment of amino acid sequences revealed that the protein contained a lipase motif and shared a medium or high similarity with lipases from other Pseudomonas strains. It could be defined as a member of subfamily I.1 lipase. Most of the recombinant proteins expressed as enzymatically active aggregates soluble in 20 mM Tris–HCl buffer (pH 8.0) containing sodium deoxycholate are remarkably different from most subfamily I.1 and I.2 members of Pseudomonas lipases expressed as inactive inclusion body formerly described in E. coli. The recombinant lipase (rPFL) was purified to homogeneity by Ni-NTA affinity chromatography and Sephacryl S-200 gel filtration chromatography. The purified lipase was stable in broad ranges of temperatures and pH values, with the optimal temperature and pH value being 55 °C and 9.0, respectively. Its activity was found to increase in the presence of metal ions such as Ca2+, Sn2+ and some non-ionic surfactants. In addition, rPFL was activated by and remained stable in a series of water-miscible organic solvents solutions and highly tolerant to some water-immiscible organic solvents. These features render this novel lipase attraction for biotechnological applications in the field of organic synthesis and detergent additives.  相似文献   

6.
An extracellular haloalkaliphilic thermostable α-amylase producing archaeon was isolated from the saltwater Lake Urmia and identified as Halorubrum xinjiangense on the basis of morphological, biochemical, and molecular properties. The enzyme was purified to an electrophoretically homogenous state by 80 % cold ethanol precipitation, followed by affinity chromatography. The concentrated pure amylase was eluted as a single peak on fast protein liquid chromatography. The molecular mass of the purified enzyme was about 60 kDa, with a pI value of 4.5. Maximum amylase activity was at 4 M NaCl or 4.5 M KCl, 70 °C, and pH 8.5. The K m and V max of the enzyme were determined as 3.8 mg ml?1 and 12.4 U mg?1, respectively. The pure amylase was stable in the presence of SDS, detergents, and organic solvents. In addition, the enzyme (20 U) hydrolyzed 69 % of the wheat starch after a 2-h incubation at 70 °C in an aqueous/hexadecane two-phase system.  相似文献   

7.
Microorganisms associated with marine sponges are potential resources for marine enzymes. In this study, culture-independent metagenomic approach was used to isolate lipases from the complex microbiome of the sponge Ircinia sp. obtained from the South China Sea. A metagenomic library was constructed, containing 6568 clones, and functional screening on 1 % tributyrin agar resulted in the identification of a positive lipase clone (35F4). Following sequence analysis 35F4 clone was found to contain a putative lipase gene lipA. Sequence analysis of the predicted amino acid sequence of LipA revealed that it is a member of subfamily I.1 of lipases, with 63 % amino acid similarity to the lactonizing lipase from Aeromonas veronii (WP_021231793). Based on the predicted secondary structure, LipA was predicted to be an alkaline enzyme by sequence/structure analysis. Heterologous expression of lipA in E. coli BL21 (DE3) was performed and the characterization of the recombinant enzyme LipA showed that it is an alkaline enzyme with high tolerance to organic solvents. The isolated lipase LipA was active in the broad alkaline range, with the highest activity at pH 9.0, and had a high level of stability over a pH range of 7.0–12.0. The activity of LipA was increased in the presence of 5 mM Ca2+ and some organic solvents, e.g. methanol, acetone and isopropanol. The optimum temperature for the activity of LipA is 40 °C and the molecular weight of LipA was determined to be ~30 kDa by SDS-PAGE. LipA is an alkaline lipase and shows good tolerance to some organic solvents, which make it of potential utility in the detergent industry and enzyme mediated organic synthesis. The result of this study has broadened the diversity of known lipolytic genes and demonstrated that marine sponges are an important source for new enzymes.  相似文献   

8.
The study was done to isolate, identify, and characterize a good lipolytic strain from soil. Lipolytic strain isolation was done using tributyrin agar medium. The biochemical testing and 16S rRNA gene sequencing analysis was done for identification. The enzyme was purified using ammonium sulfate precipitation and column chromatography. Results have shown a novel high lipolytic strain of P. aeruginosa JCM5962(T), isolated from soil of sugarcane field. The 16S rRNA sequence analysis confirmed the strain as P. aeruginosa JCM5962(T); further, the sequence was submitted to Genbank (KX946966.1). The isolate produced an extracellular lipase which was purified as single band of 31 kDa. Maximum lipase activity was observed at 50 °C and pH 8.0. Activity was enhanced in the presence of cobalt and benzene solvent, whereas mercury, sodium dodecyl sulfate, and chloroform inhibited it. The enzyme’s marked stability and activity at high temperature, alkaline pH and organic solvents suggest that this can be effectively used in a variety of applications in industries and as biotechnological tools.  相似文献   

9.
Using enrichment procedures, a lipolytic strain was isolated from a stinky tofu brine and was identified as Bacillus amyloliquefaciens (named B. amyloliquefaciens Nsic-8) by morphological, physiological, biochemical tests and 16S rDNA sequence analysis. Meanwhile, the key enzyme gene (named lip BA) involved in ester metabolism was obtained from Nsic-8 with the assistance of homology analysis. The novel gene has an open reading frame of 645 bp, and encodes a 214-amino-acid lipase (LipBA). The deduced amino acid sequence shows the highest identity with the lipase from B. amyloliquefaciens IT-45 (NCBI database) and belongs to the family of triacylglycerol lipase (EC 3.1.1.3). The lipase gene was expressed in Escherichia coli BL21(DE3) using plasmid pET-28a. The enzyme activity and specific activity were 250 ± 16 U/ml and 1750 ± 153 U/mg, respectively. The optimum pH and temperature of the recombinant enzyme were 9.0 and 40 °C respectively. LipBA showed much higher stability under alkaline conditions and was stable at pH 7.0–11.0. The Km and Vmax values of purified LipBA using 4-nitrophenyl palmitate as the substrate were 1.04 ± 0.06 mM and 119.05 ± 7.16 μmol/(ml min), respectively. After purification, recombinant lipase was immobilized with the optimal conditions (immobilization time 3 h at 30 °C, with 92 % enzyme recovery) and the immobilized enzyme was applied in biodiesel production. This is the first report of the lipase activity and lipase gene obtained from B. amyloliquefaciens (including wild strain and recombinant strain) and the recombinant LipBA with the detailed enzymatic properties. Also the preliminary study of the transesterification shows the potential value in biodiesel production applications.  相似文献   

10.
Microorganisms can produce lipases with different biochemical characteristics making necessary the screening of new lipase-producing strains for different industrial applications. In this study, 90 microbial strains were screened as potential lipase producers using a sensitive agar plate method with a suitable medium supplemented with Tween 20 and also a liquid culture supplemented with olive oil. The highest cell growth and lipase production for Candida viswanathii were observed in triolein and oleic acid when used as the only pure carbon source. Renewable low-cost triacylglycerols supported the best cell growth, and olive oil was found to be the best inducer for lipase production (19.50 g/L and 58.50 U). The selected conditions for enzyme production were found with yeast extract as nitrogen source and 1.5 % (w/v) olive oil (85.70 U) that resulted in a good cell growth yield (YX/S?=?1.234 g/g) and lipase productivity (1.204 U/h) after 72 h of shake-flask cultivation. C. viswanathii lipase presented high hydrolytic activity on esters bonds of triacylglycerols of long-chain, and this strain can be considered an important candidate for future applications in chemical industries.  相似文献   

11.
A thermophilic lipase gene of Geobacillus stearothermophilus JC was cloned and expressed in a pET 28-a (+) expression vector. The biochemical properties of the recombinant enzyme and its enantioselective hydrolysis of (RS)-1-phenylethyl acetate were studied. Removal of the signal peptide greatly increased the enzyme’s expression level by 4.3 times. The purified JC lipase had an optimum temperature of 55°C and optimum pH of 9. Furthermore, comparisons with other enzymes suggest that a few amino acid alterations may significantly change the thermostability of this enzyme. The hydrolysis of (RS)-1-phenylethyl acetate with the crude recombinant JC lipase at 25°C produce (R)-1-phenylethanol in 97.7% e.e. and 46.1% yield after 24 h, corresponding to an E value of 237.  相似文献   

12.
The human oral metagenomic DNA cloned into plasmid pUC19 was used to construct a DNA library in Escherichia coli. Functional screening of 40,000 metagenomic clones led to identification of a clone LIP2 that exhibited halo on tributyrin agar plate. Sequence analysis of LIP2 insert DNA revealed a 939 bp ORF (omlip1) which showed homology to lipase 1 of Acinetobacter junii SH205. The omlip1 ORF was cloned and expressed in E. coli BL21 (DE3) using pET expression system. The recombinant enzyme was purified to homogeneity and the biochemical properties were studied. The purified OMLip1 hydrolyzed p-nitrophenyl esters and triacylglycerol esters of medium and long chain fatty acids, indicating the enzyme is a true lipase. The purified protein exhibited a pH and temperature optima of 7 and 37 °C respectively. The lipase was found to be stable at pH range of 6–7 and at temperatures lower than 40 °C. Importantly, the enzyme activity was unaltered, by the presence or absence of many divalent cations. The metal ion insensitivity of OMLip1offers its potential use in industrial processes.  相似文献   

13.
An extracellular lipase-producing bacterium was isolated from a fecal sample of lion-tailed macaque (Macaca silenus), an endangered Old World monkey that is endemic to the Western Ghats of South India. Morphological, biochemical and molecular analyses identified the bacterium as Serratia marcescens. Production of lipase was investigated in shake-flask culture. Optimum tributyrin concentration of 1.5 % was found to be the most suitable triglyceride to increase lipase production (13.3 U ml?1). The next best lipid source observed was olive oil (11.94 U ml?1), followed by castor oil, coconut oil and palm oil. Analyzing the effect of different carbon sources on lipase production revealed that 2 % glucose yielded higher lipase production than the other tested carbon sources. Investigations on suitable nitrogen source for lipase production revealed that 2 % meat extract yielded higher lipase production. The most suitable trace element for maximum lipase production was zinc sulfate, followed by magnesium sulfate and copper sulfate. Partial characterization of the crude lipase revealed that pH 7.0 and a temperature of 40 °C gave optimal lipase activity. Enzymatic activity of the crude sample was retained over a wide temperature range (20–75 °C), and 70 % of enzyme activity was retained at 60 °C. Testing the effect of various organic solvents on lipase activity revealed that hexadecane increased lipase activity by 85 % over the control.  相似文献   

14.
An organic solvent-tolerant lipase from newly isolated Pseudomonas aeruginosa LX1 has been purified by ammonium sulfate precipitation and ion-exchange chromatography leading to 4.3-fold purification and 41.1% recovery. The purified lipase from P. aeruginosa LX1 was homogeneous as determined by SDS-PAGE, and the molecular mass was estimated to be 56 kDa. The optimum pH and temperature for lipase activity were found to be 7.0 and 40 °C, respectively. The lipase was stable in the pH range 4.5–12.0 and at temperatures below 50 °C. Its hydrolytic activity was found to be highest towards p-nitrophenyl palmitate (C16) among the various p-nitrophenol esters investigated. The lipase displayed higher stability in the presence of various organic solvents, such as n-hexadecane, isooctane, n-hexane, DMSO, and DMF, than in the absence of an organic solvent. The immobilized lipase was more stable in the presence of n-hexadecane, tert-butanol, and acetonitrile. The transesterification activity of the lipase from P. aeruginosa LX1 indicated that it is a potential biocatalyst for biodiesel production.  相似文献   

15.
The mature ARM lipase gene was cloned into the pTrcHis expression vector and over-expressed in Escherichia coli TOP10 host. The optimum lipase expression was obtained after 18 h post induction incubation with 1.0 mM IPTG, where the lipase activity was approximately 1623-fold higher than wild type. A rapid, high efficient, one-step purification of the His-tagged recombinant lipase was achieved using immobilized metal affinity chromatography with 63.2% recovery and purification factor of 14.6. The purified lipase was characterized as a high active (7092 U mg−1), serine-hydrolase, thermostable, organic solvent tolerant, 1,3-specific lipase with a molecular weight of about 44 kDa. The enzyme was a monomer with disulfide bond(s) in its structure, but was not a metalloenzyme. ARM lipase was active in a broad range of temperature and pH with optimum lipolytic activity at pH 8.0 and 65 °C. The enzyme retained 50% residual activity at pH 6.0-7.0, 50 °C for more than 150 min.  相似文献   

16.
Phenylalanine ammonia-lyase is the first enzyme of general phenylpropanoid pathway. A PAL gene, designated as BoPAL1, was cloned from a Bambusa oldhamii cDNA library. The open reading frame of BoPAL1 was 2,139 bp in size and predicted to encode a 712-amino acid polypeptide. BoPAL1 was the first intronless PAL gene found in angiosperm plant. Several putative cis-acting elements such as P box, GT-1motif, and SOLIPs involved in light responsiveness were found in the 5??-flanking sequence of BoPAL1 which was obtained by TAIL-PCR method. Recombinant BoPAL1 protein expressed in Pichia pastoris was active. The optimum temperature and pH for BoPAL1 activity was 50°C and 9.0, respectively. The molecular mass of recombinant BoPAL1 was estimated as 323 kDa using gel filtration chromatography and the molecular mass of full-length BoPAL was about 80 kDa, indicating that BoPAL1 presents as a homotetramer. The K m and k cat values of BoPAL1 for L-Phe were 1.01 mM and 10.11 s?1, respectively. The recombinant protein had similar biochemical properties with PALs reported in other plants.  相似文献   

17.
Extracellular lipase from Bacillus coagulans BTS-3 was immobilized on (3 Å × 1.5 mm) molecular sieve. The molecular sieve showed approximately 68.48% binding efficiency for lipase (specific activity 55 IU mg?1). The immobilized enzyme achieved approx 90% conversion of acetic acid and 4-nitrophenol (100 mM each) into 4-nitrophenyl acetate in n-heptane at 65°C in 3 h. When alkane of C-chain length other than n-heptane was used as the organic solvent, the conversion of 4-nitrophenol and acetic acid was found to decrease. About 88.6% conversion of the reactants into ester was achieved when reactants were used at molar ratio of 1:1. The immobilized lipase brought about conversion of approximately 58% for esterification of 4-nitrophenol and acetic acid into 4-nitrophenyl acetate at a temperature of 65°C after reuse for 5 cycles.  相似文献   

18.
Lipases have found a number of commercial applications. However, thermostable lipase immobilized on nanoparticle is not extensively characterized. In this study, a recombinant thermostable lipase (designated as TtL) from Thermus thermophilus WL was expressed in Escherichia coli and immobilized onto 3-APTES-modified Fe3O4@SiO2 supermagnetic nanoparticles. Based on analyses with tricine–sodium dodecyl sulfate–polyacrylamide gel electrophoresis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer observation, the diameter of immobilized lipase nanoparticle was 18.4 (±2.4)?nm, and its saturation magnetization value was 52.3 emu/g. The immobilized lipase could be separated from the reaction medium rapidly and easily in a magnetic field. The biochemical characterizations revealed that, comparing with the free one, the immobilized lipase exhibited better resistance to temperature, pH, metal ions, enzyme inhibitors, and detergents. The K m value for the immobilized TtL (2.56 mg/mL) was found to be lower than that of the free one (3.74 mg/mL), showing that the immobilization improved the affinity of lipase for its substrate. In addition, the immobilized TtL exhibited good reusability. It retained more than 79.5 % of its initial activity after reusing for 10 cycles. Therefore, our study presented that the possibility of the efficient reuse of the thermostable lipase immobilized on supermagnetic nanoparticles made it attractive from the viewpoint of practical application.  相似文献   

19.
Bacillus smithii BTMS 11, isolated from marine sediment, produced alkaline and thermostable lipase. The enzyme was purified to homogeneity by ammonium sulfate precipitation and ion exchange chromatography which resulted in 0.51 % final yield and a 4.33 fold of purification. The purified enzyme was found to have a specific activity of 360 IU/mg protein. SDS-PAGE analyses, under non-reducing and reducing conditions, yielded a single band of 45 kDa indicating the single polypeptide nature of the enzyme and zymogram analysis using methylumbelliferyl butyrate as substrate confirmed the lipolytic activity of the protein band. The enzyme was found to have 50 °C and pH 8.0 as optimum conditions for maximal activity. However, the enzyme was active over wide range of temperatures (30–80 °C) and pH (7.0–10.0). Effect of a number of metal salts, solvents, surfactants, and other typical enzyme inhibitors on lipase activity was studied to determine the novel characteristics of the enzyme. More than 90 % of the enzyme activity was observed even after 3 h of incubation in the presence of commercial detergents Surf, Sunlight, Ariel, Henko, Tide and Ujala indicating the detergent compatibility of B. smithii lipase. The enzyme was also found to be efficient in stain removal from cotton cloths. Further it was observed that the enzyme could catalyse ester synthesis between fatty acids of varying carbon chain lengths and methanol with high preference for medium to long chain fatty acids showing 70 % of esterification. Results of the study indicated scope for application of this marine bacterial lipase in various industries.  相似文献   

20.
Expression of recombinant proteins as inclusion bodies in bacteria is one of the most efficient ways to produce cloned proteins, as long as the inclusion bodies can be successfully refolded. In this study, the different parameters were investigated and optimized on the refolding of denatured lipase. The maximum lipase activity of 5000 U/L was obtained after incubation of denatured enzyme in a refolding buffer containing 20 mM Tris–HCl (pH 7.0), 1 mM Ca2+ at 20 °C. Then, the refolded lipase was purified to homogeneity by anion exchange chromatography. The purified refolded lipase was stable in broad ranges of temperatures and pH values, as well as in a series of water-miscible organic solvents. In addition, some water-immiscible organic solvents, such as petroleum ether and isopropyl ether, could reduce the polarity and increase the nonpolarity of the refolding system. The results of Fourier transform infrared (FT-IR) microspectroscopy were the first to confirm that lipase refolding could be further improved in the presence of organic solvents. The purified refolded lipase could enantioselectively hydrolyze trans-3-(4-methoxyphenyl) glycidic acid methyl ester [(±)-MPGM]. These features render the lipase attraction for biotechnological applications in the field of organic synthesis and pharmaceutical industry.  相似文献   

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