Nitrophenyl Palmitate Research Articles

Screening of lipase carriers for reactions in water, biphasic and pure organic solvent systems.

In bioprocesses lipases are typically used in immobilized form, irrespective of type of reaction systems, to ensure an even distribution of catalysts in water restricted media and/or to facilitate separation and reuse. In these studies we report on the selection of appropriate enzyme-carrier preparation for hydrolysis reaction in aqueous and biphasic systems and transesterification in organic solvent. For this Candida rugosa lipase was bound by adsorption or covalent attachment onto various carriers to give 24 preparations. Selection of proper preparation was based on reactivity, thermal stability (4 h at 60°C), possibility of drying and operational stability in 17-23 successive batch processes of 4-nitrophenyl palmitate hydrolysis in water. Activity of preparations varied from 20 to 5100 U∙mL(-1) but the most stable preparations were those of moderate activity: bound by adsorption or covalent attachment to NH₂-Kieselgel or acrylic carrier (retained activity over 90%). Selected preparations were used for hydrolysis of ethyl (1-butyryloxyethyl)-phenylphosphinate in biphasic system, and, after drying, in ethyl (1-hydroxyethyl)-phenyl-phosphinate transesterification. In this study operational stability was the principal criterion of selection. In water system, lipase covalently bound to NH₂-Kieselgel was the best - preserved 50% of initial activity in consecutive batch processes. In biphasic system and lipase covalently bound to acrylic and NH₂-Kieselgel the values were 90 or 77%, respectively, whereas in organic solvent, when lipase was immobilized on NH₂-Kieselgel by adsorption, it was 50%. Thus, NH₂-Kieselgel appears to be an universal matrix for investigated lipase immobilization and can be used in all reaction systems.

Isolation identification and biochemical characterization of a novel halo-tolerant lipase from the metagenome of the marine sponge Haliclona simulans

BackgroundLipases (EC 3.1.1.3) catalyze the hydrolysis of triacyl glycerol to glycerol and are involved in the synthesis of both short chain and long chain acylglycerols. They are widely used industrially in various applications, such as baking, laundry detergents and as biocatalysts in alternative energy strategies. Marine ecosystems are known to represent a large reservoir of biodiversity with respect to industrially useful enzymes. However the vast majority of microorganisms within these ecosystems are not readily culturable. Functional metagenomic based approaches provide a solution to this problem by facilitating the identification of novel enzymes such as the halo-tolerant lipase identified in this study from a marine sponge metagenome.ResultsA metagenomic library was constructed from the marine sponge Haliclona simulans in the pCC1fos vector, containing approximately 48,000 fosmid clones. High throughput plate screening on 1% tributyrin agar resulted in the identification of 58 positive lipase clones. Following sequence analysis of the 10 most highly active fosmid clones the pCC1fos53E1 clone was found to contain a putative lipase gene lpc53E1, encoded by 387 amino acids and with a predicted molecular mass of 41.87 kDa. Sequence analysis of the predicted amino acid sequence of Lpc53E1 revealed that it is a member of the group VIII family of lipases possessing the SXTK motif, related to type C β-lactamases. Heterologous expression of lpc53E1 in E. coli and the subsequent biochemical characterization of the recombinant protein, showed an enzyme with the highest substrate specificity for long chain fatty acyl esters. Optimal activity was observed with p- nitrophenyl palmitate (C16) at 40°C, in the presence of 5 M NaCl at pH 7; while in addition the recombinant enzyme displayed activity across broad pH (3–12) and temperature (4 -60°C) ranges and high levels of stability in the presence of various solvents at NaCl concentrations as high as 5 M and at temperatures ranging from 10 to 80°C. A maximum lipase activity of 2,700 U/mg was observed with 10 mM p-nitrophenyl palmitate as substrate, in the presence of 5 mM Ca2+ and 5 M NaCl, and a reaction time of 15 min at pH 7 and 40°C; while KM and Vmax values were calculated to be 1.093 mM-1 and 50 μmol/min, respectively.ConclusionWe have isolated a novel halo tolerant lipase following a functional screen of a marine sponge fosmid metagenomic library. The activity and stability profile of the recombinant enzyme over a wide range of salinity, pH and temperature; and in the presence of organic solvent and metal ions suggests a utility for this enzyme in a variety of industrial applications.

Purification and characterization of a secretory lipolytic enzyme, MgLIP2, from Malassezia globosa

Malassezia globosa is a lipid-dependent yeast that is found on the human skin and is associated with various skin disorders, including dandruff and seborrhoeic dermatitis (SD). Despite its important role in skin diseases, the molecular basis for its pathogenicity is poorly understood. The current hypothesis is that dandruff and SD are linked to fatty acid metabolism and secretory lipolytic enzymes, which hydrolyse sebaceous lipids and release irritating free fatty acids. A previous genomic analysis of M. globosa identified a family of 13 homologous genes predicted to encode secreted lipases. We have also reported that M. globosa had significantly higher extracellular lipase activity compared with other species. To identify the major secretory lipases of this yeast during its growth, we successfully purified and characterized an extracellular lipase MgLIP2. Based on MALDI-TOF MS, the peptide mass fingerprint of a tryptically digested protein MgLIP2 corresponded to ORF MGL_4054 of M. globosa. This lipase showed high esterase activity against 4-nitrophenyl palmitate and 1-naphthyl palmitate but not 1-naphthyl acetate. This enzyme had optimal activity at 30 °C and pH 5.0. Furthermore, the activity significantly increased in the presence of Triton X-100 and was partially inhibited by PMSF but was unaffected by univalent and divalent metal ions.

Ester synthesis using Candida rugosa lipase immobilized on magnetic nanoparticles

Magnetic nanoparticles were synthesized by co-precipitation under hydrothermal conditions. The average diameter of the magnetic nanoparticles was found to be in the range of 15 ± 5 nm with an average surface area of 112.15 m2 g−1. Immobilization of lipase on magnetite nanoparticles was confirmed by FTIR, differential scanning calorimetry and thermal gravimetric analysis. The activation energy of the free enzyme was 1.9-fold higher than that of the immobilized lipase for hydrolytic reactions. Additionally, the lower KM and higher Vmax values of the immobilized enzyme for hydrolysis of 4-nitrophenyl palmitate indicated an increased efficiency of the immobilized lipase. The immobilized lipase exhibited higher esterification efficiency compared with free lipase for synthesis of ethyl isovalerate. It also exhibited fairly good reusability, with about 8.5% reduction in esterification efficiency for ethyl isovalerate synthesis over ten cycles of reuse.

An extra-cellular alkaline metallolipase from Bacillus licheniformisMTCC 6824: Purification and biochemical characterization

An extra-cellular lipase produced by Bacillus licheniformis MTCC 6824 was purified to homogeneity by ammonium sulphate fractionation, ethanol/ether precipitation, dialysis, followed by anion-exchange chromatography on Amberlite IRA 410 (Cl− form) and gel exclusion chromatography on Sephadex G 100 using Tris–HCl buffer (pH 8.0). The crude lipase extract had an activity of 41.7LU/ml of culture medium when the bacterium was cultured for 48h at 37°C and pH 8.0 with nutrient broth supplemented with sardine oil as carbon source. The enzyme was purified 208-fold with 8.36% recovery and a specific activity of 520LU/mg after gel exclusion chromatography. The pure enzyme is a monomeric protein and has an apparent molecular mass of 74.8kDa. The lipase had a Vmax and Km of 0.64mM/mg/min and 29mM, respectively, with 4-nitro phenylpalmitate as a substrate, as calculated from the Lineweaver–Burk plot. The lipase exhibited optimum activity at 45°C and pH 8.0, respectively. The enzyme had half-lives (T1/2) of 82min at 45°C, and 48min at 55°C. The catalytic activity was enhanced by Ca2+ (18%) and Mg2+ (12%) at 30mM. The lipase was inhibited by Co2+, Cu2+, Zn2+, Fe2 even at low concentration (10mM). EDTA, at 70mM concentration, significantly inhibited the activity of lipase. Phenyl methyl sulfonyl fluoride (PMSF, 70mM) completely inactivated the original lipase. A combination of Ca2+ and sorbitol induced a synergistic effect on the activity of lipase with a significantly high residual activity (100%), even after 45min, as compared to 91.5% when incubated with Ca2+ alone. The lipase was found to be hydrolytically resistant toward triacylglycerols with more double bonds.

Immobilization ofCandida rugosalipase on Magnetized Dacron: Kinetic Study

Candida rugosa lipase has been covalently immobilized on ferromagnetic azide polyethyleneterepthalate (Dacron) with specific activity retention of 16% for 4-nitrophenyl palmitate and 24% for hydrolysis of triolein in hexane. The immobilized enzyme was more thermal stable than the soluble one, retaining 78.8% of the activity after 1 h at 60 degrees C. Also, this immobilized derivative was stable at the storage at 4 degrees C. It has been used 5 cycles for pNPP hydrolysis without loss of activity. Soluble and immobilized Candida rugosa lipase showed a Michaelian behavior for fatty acid 4-nitrophenyl esters and different apparent K(M) values: 0.110 mM and 0.124 mM (4-nitrophenyl palmitate - C16); 0.193 mM and 0.235 mM (4-nitrophenyl laurate - C12) and 0.206 mM and 0.119 mM (4-nitrophenyl butyrate - C4), respectively. The immobilized lipase was more efficient for catalyzing the hydrolysis of 4-nitrophenyl esters with short chain length fatty acid (4-NPB - C4) than soluble enzyme. The ferromagnetic Dacron-lipase derivative was able to catalyze the synthesis of triolein from glycerol and oleic acid with 50% of conversion after 72 h at 40 degrees C.

Lipase production by yeasts from extra virgin olive oil

Newly produced olive oil has an opalescent appearance due to the presence of solid particles and micro-drops of vegetation water from the fruits. Some of our recent microbiological research has shown that a rich micro-flora is present in the suspended fraction of the freshly produced olive oil capable of improving the quality of the oil through the hydrolysis of the oleuropein. Present research however has, for the first time, demonstrated the presence of lipase-positive yeasts in some samples of extra virgin olive oil which can lower the quality of the oil through the hydrolysis of the triglycerides. The tests performed with yeasts of our collection, previously isolated from olive oil, demonstrated that two lipase-producing yeast strains named Saccharomyces cerevisiae 1525 and Williopsis californica 1639 were able to hydrolyse different specific synthetic substrates represented by p-nitrophenyl stearate, 4-nitrophenyl palmitate, tripalmitin and triolein as well as olive oil triglycerides. The lipase activity in S. cerevisiae 1525 was confined to the whole cells, whereas in W. californica 1639 it was also detected in the extracellular fraction. The enzyme activity in both yeasts was influenced by the ratio of the aqueous to the organic phase reaching its maximum value in S. cerevisiae 1525 when the water added to the olive oil was present in a ratio of 0.25% (v/v), whereas in W. californica 1639 the optimal ratio was 1% (v/v). Furthermore, the free fatty acids of olive oil proved to be good inducers of lipase activity in both yeasts. The microbiological analysis carried out on commercial extra virgin olive oil, produced in four different geographic areas, demonstrated that the presence of lipase-producing yeast varied from zero to 56% of the total yeasts detected, according to the source of oil samples. The discovery of lipase-positive yeasts in some extra virgin olive oils leads us to believe that yeasts are able to contribute in a positive or negative way towards the organological quality of the olive oil.

Activity of bile-salt-stimulated human milk lipase in the presence of liposomes and mixed taurocholate-phosphatidylcholine micelles

(1) The interaction of bile-salt-stimulated human milk lipase and liposomal membranes has been investigated in the presence or absence of sodium taurocholate. Freshly purified enzyme enhances the permeability of liposomal membranes but thermally inactivated enzyme does not. (2) The ability of the enzyme to catalyze the hydrolisys of a relatively hydrophilic substrate, 4-nitrophenyl acetate, and a more hydrophobic substrate, 4-nitrophenyl palmitate, has also been measured in media containing small unilamelar vesicles of egg phosphatidylcholine in both the absence and presence of taurocholate, and also in the presence of free taurocholate in the absence of liposomes. (3) The enzyme-catalyzed hydrolysis of 4-nitrophenyl acetate is enhanced in all of these systems, but 4-nitrophenyl palmitate is protected from enzymic attack in the phosphatidylcholine-bile salt systems. If free taurocholate be present in the system before 4-nitrophenyl palmitate is added, then, and only then, is enzymic activity observed. (4) These results have been interpreted in terms of the importance of the microenvironment around the substrate and the role played by the bile salt surfactant in stimulating the enzyme.

Screening for Fungal Lipase Using Chromogenic Lipid Substrates

(1986). Screening for Fungal Lipase Using Chromogenic Lipid Substrates. Mycologia: Vol. 78, No. 2, pp. 298-300.