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Smichi N.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Fendri A.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Chaabouni R.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Rebah F.B.,Institute National Des Science Et Technologies Of La Mer | And 2 more authors.
Applied Biochemistry and Biotechnology | Year: 2010

A lipolytic activity was located in the sardine digestive glands (pyloric caeca), from which a sardine digestive lipase (SaDL) was purified. Pure SaDL has a molecular mass of 43 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The enzyme was found to be more active on short-chain triacylglycerols than on long-chain ones. SaDL does not present the interfacial activation phenomenon. Control experiments were performed under the same experimental conditions, with dromedary and turkey pancreatic lipases and showed a positive interfacial activation phenomenon. Sodium deoxycholate (NaDC) has an inhibitory effect on the lipase activity. The pure enzyme lost 40% of its activity in presence of 8 mM NaDC. SaDL was found to be mostly stable at low pH values. Interestingly, no colipase was detected in the sardine pyloric caeca. Analogous results were reported for the scorpion and the crab digestive systems. This is in line with the idea that colipase might has evolved in mammal animals simultaneously with the appearance of an exocrine pancreas. No similarity was found between the NH2-terminal amino acid residues of SaDL and those of lipases from the digestive tract of other species. Altogether, these results suggest that SaDL is a member of a new group of lipases belonging to aquatic species. © 2010 Springer Science+Business Media, LLC.


Kharrat N.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Ali Y.B.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Marzouk S.,Laboratoire Of Chimie Industrielle Ii | Gargouri Y.-T.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Karra-Chaabouni M.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases
Process Biochemistry | Year: 2011

Rhizopus oryzae lipase (ROL) was immobilized by physical adsorption onto silica aerogels. The functional properties of immobilized lipase were determined and compared to the soluble lipase ones. The optimum temperature for both free and immobilized lipase activities was 37 °C. We found that the immobilization of R. oryzae lipase onto silica aerogels increased remarkably its stability at high temperatures and within a wade pH range. Besides the immobilized enzyme exhibited a high tolerance to apolar solvent and retained its fully activity in suspension after 4 months of storage at 4 °C. This immobilized biocatalyst is applied in n-butyl oleate synthesis by esterification of oleic acid with n-butanol, using hexane as an organic solvent. The best conversion yield of the ester butyl oleate was obtained with the immobilized lipase (80% versus 35% with the free lipase). This catalytic esterification has been carried on the presence of hexane at 37 °C with oleic acid to butanol molar ratio of 1:1 and 450 IU of immobilized lipase. Furthermore, the reuse of the lipase immobilized by adsorption allowed us to observe that its can achieved 12 successive cycles, without a significant loss of its catalytic activity. Such results revealed good potential for recycling under non-aqueous system. © 2011 Elsevier Ltd. All rights reserved.


Aissa I.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Sellami M.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Kamoun A.,Laboratoire Of Chimie Industrielle Ii | Gargouri Y.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Miled N.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases
Current Chemical Biology | Year: 2012

Wax esters have a variety of biotechnological usage in cosmetic and pharmaceutical products. Synthesized wax esters can be an alternative to sperm whale being rare. The ability of a non-commercial immobilized lipase from Rhizopus oryzae to catalyze the synthesis of wax esters was investigated in organic media. Wax esters were obtained by esterification of myristic, palmitic, stearic or oleic acids with cetyl alcohol. Response surface methodology was used to evaluate the effects of the temperature, the enzyme amount and the volume of hexane on the wax esters production yields. Under optimal conditions, high conversion yields (92-95%) of saturated fatty acids were reached within a reaction time of 30 min whereas a yield of 93.5% was obtained for cetyl oleate after 60 min. The synthesized esters were purified using a silica gel column. The immobilized Rhizopus oryzae lipase was successfully reused in 20 repeated cycles with no significant decrease in the final conversion yields. This makes it a promising candidate for the development of a highly effective set-up for the production of wax esters. © 2012 Bentham Science Publishers.


Chaari A.,University of Versailles | Horchani H.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Frikha F.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Verger R.,Aix - Marseille University | And 2 more authors.
International Journal of Biological Macromolecules | Year: 2013

Due to the involvement of α-Synuclein (α-Syn) in lipid transport and its role in the normal function and in the pathology of Parkinson disease, it is important to study first the surface properties of the protein at the air/water interface and second its behavior related to biological membranes. For this purpose, the monomolecular film technique was used as membrane model to compare the interactions with various phospholipids of monomeric and fibrillar forms of α-Syn. We have determined the equilibrium surface pressure of the two forms of α-Syn (monomeric and fibrillar form) at the air/water interface. The surface pressures reached by monomeric α-Syn were shown to be higher than the ones of fibrillar α-Syn and similar to the value obtained by mellitin, a lytic peptide of bee venom, which has been described as "protein detergent". The monomeric α-Syn adsorbed more rapidly at the air/water interface with a maximal adsorption rate at least 60-times higher than the fibrillar form. In the presence of a phospholipid monolayer, the surface activities of two α-Syn forms are much greater than observed at the air/water interface. Also we can show that the fibrillar form of α-Syn have a higher value of critical pressure than the monomeric one for the cow brain extract and the Phospatidyl Glycerol (an anionic phospholipid) which confirm its higher affinity for the anionic phospholipid than the monomeric form. According these results, we can suggest that this aggregate form have important implications for the pathological activity and, therefore, for the associated neurotoxicity which can results in layer disruption and cell leakage. © 2013.


Aloui F.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Maazoun B.,The Factory Confiserie TRIKI Le Moulin | Gargouri Y.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Miled N.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases
Journal of Food Science and Technology | Year: 2015

Oil bleeding during storage oleaginous seeds based confectionery products is a major problem affecting acceptance by consumers. Halva is a popular sweet food prepared from a sesame paste and a sugar mixture. The objective of this work was to improve the oil retention in this product by incorporating commercial fibers and emulsifiers: soya lecithin and monoglycerides (MG1 or MG2) during manufacturing. Oil retention yield was optimized on small batches, by response surface methodology using a central composite design applied with two factors, emulsifier concentration (0.25–2.25 %) and fibers concentration (0–2 %) at three levels. A centrifugation test was optimized to assess oil retention in halva samples. The experimental response (oil retention) was fitted with quadratic equations for each emulsifier, using multiple regression analysis. The emulsion stability increased with increasing the emulsifier concentration, particularly to 2.25 %. The oil bleeding assessed at 45 °C was slow but yielded similar results to those estimated by centrifugation test. The latter seems an attractive rapid method to quantify oil retention in oleaginous seeds and crops based food matrices. At an industrial scale, the increase of MG1 concentration to 2.25 % in halva enhances the oil retention of the product but does not affect its color or textural characteristics. Microscopic observations allowed us to explain high oil retention in this product by a homogeneous dispersion of oil droplets in the aqueous phase. © 2015 Association of Food Scientists & Technologists (India)


PubMed | Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases and The Factory Confiserie TRIKI Le Moulin
Type: Journal Article | Journal: Journal of food science and technology | Year: 2016

Oil bleeding during storage oleaginous seeds based confectionery products is a major problem affecting acceptance by consumers. Halva is a popular sweet food prepared from a sesame paste and a sugar mixture. The objective of this work was to improve the oil retention in this product by incorporating commercial fibers and emulsifiers: soya lecithin and monoglycerides (MG1 or MG2) during manufacturing. Oil retention yield was optimized on small batches, by response surface methodology using a central composite design applied with two factors, emulsifier concentration (0.25-2.25%) and fibers concentration (0-2%) at three levels. A centrifugation test was optimized to assess oil retention in halva samples. The experimental response (oil retention) was fitted with quadratic equations for each emulsifier, using multiple regression analysis. The emulsion stability increased with increasing the emulsifier concentration, particularly to 2.25%. The oil bleeding assessed at 45C was slow but yielded similar results to those estimated by centrifugation test. The latter seems an attractive rapid method to quantify oil retention in oleaginous seeds and crops based food matrices. At an industrial scale, the increase of MG1 concentration to 2.25% in halva enhances the oil retention of the product but does not affect its color or textural characteristics. Microscopic observations allowed us to explain high oil retention in this product by a homogeneous dispersion of oil droplets in the aqueous phase.


Amara S.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Fendri A.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Ben Salem N.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Gargouri Y.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Miled N.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases
Applied Biochemistry and Biotechnology | Year: 2010

Higher animal's lipases are well characterized; however, much less is known about lipases from mollusks. A lipolytic activity was located in the land snail (Eobania vermiculata) digestive glands (hepatopancreas), from which a snail digestive lipase (SnDL) was purified. Pure SnDL has a molecular mass of 60 kDa; it does not present the interfacial activation phenomenon. It was found to be more active on short-chain triacylglycerols than on long-chain triacylglycerols. The NH2-terminal sequence of the SnDL shows 66% of identity with the 17 NH2-terminal amino acids of a putative lipase from sea urchin (Strongylocentrotus purpuratus). No sequence identity was found with known lipases. Interestingly, neither colipase nor bile salts were detected in the snail hepatopancreas. This suggests that colipase evolved in vertebrates simultaneously with the appearance of an exocrine pancreas and a true liver which produces bile salts. Altogether, these results suggest that SnDL is a member of a new group of digestive lipases belonging to invertebrates. © 2009 Humana Press.


Fendri A.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Louati H.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Sellami M.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | Gargouri H.,Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases | And 5 more authors.
International Journal of Biological Macromolecules | Year: 2012

A lipolytic activity was located in the chicken uropygial glands, from which a carboxylesterase (CUE) was purified. Pure CUE has an apparent molecular mass of 50kDa. The purified esterase displayed its maximal activity (200U/mg) on short-chain triacylglycerols (tributyrin) at a temperature of 50°C. No significant lipolytic activity was found when medium chain (trioctanoin) or long chain (olive oil) triacylglycerols were used as substrates. The enzyme retained 75% of its maximal activity when incubated during 2h at 50°C. The NH2-terminal amino acid sequence showed similarities with the esterase purified recently from turkey pharyngeal tissue. Esterase activity remains stable after its incubation during 30min in presence of organic solvents such as hexane or butanol. CUE is a serine enzyme since it was inactivated by phenylmethanesulphonyl fluoride (PMSF), a serine-specific inhibitor. The purified enzyme, which tolerates the presence of some organic solvent and a high temperature, can be used in non-aqueous synthesis reactions. Hence, the uropygial esterase immobilised onto CaCO3 was tested to produce the isoamyl and the butyl acetate (flavour esters). Reactions were performed at 50°C in presence of hexane. High synthesis yields of 91 and 67.8% were obtained for isoamyl and butyl acetate, respectively. © 2012 Elsevier B.V.


PubMed | Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases
Type: | Journal: Biotechnology and applied biochemistry | Year: 2015

A lipolytic activity was located in the annular seabream pyloric caeca, from which a digestive lipase (AsDL) was purified. Pure AsDL has an apparent molecular mass of 50kDa. The purified lipase is thermoactive as it displays its maximal activity on short- and long-chain triacylglycerols at a temperature of 50C. The enzyme is alkaline resistant as it retains 90% of its maximal activity when incubated during 1H at pH 10. No colipase was detected in the annular seabream pyloric caeca. Similar results were reported for the sardine and the gray mullet digestive systems. This is in line with the idea that colipase might have evolved in mammal animals simultaneously with the appearance of an exocrine pancreas. AsDL is a serine enzyme, like all known lipases from different origins. Interestingly, the pure lipase was found to be insensitive to Triton X-100, a synthetic detergent, addition even at a concentration as high as 12mM. The purified enzyme has potential applications in detergent and food industry because of its thermal activity and alkaline nature.


PubMed | Laboratoire Of Biochimie Et Of Genie Enzymatique Des Lipases
Type: Journal Article | Journal: International journal of biological macromolecules | Year: 2016

Two lipases from Fusarium solani, FSL and FSL2, were efficiently expressed in Pichia pastoris. To check the influence of the expression on interfacial properties of FSL and to study kinetic properties of FSL2, interfacial parameters of FSL2, native FSL, untagged recombinant and tagged recombinant forms of FSL were compared using the monomolecular film technique. Kinetic study on the dependence of the stereoselectivity of these lipases on the surface pressure was performed using three dicaprin isomers spread in the form of monomolecular films at the air-water interface. The FSL2 seems to have an important penetration power with a preference for adjacent ester groups and the heterologous expression accompanied or not with the N-His-tag extension on the FSL were found to modify the pressure preference and increase the catalytic hydrolysis rate of three dicaprin isomers. The heterologous expression was found to preserve the FSL regioselectivity without affecting its stereospecificity at high and low surface pressure. The evaluation of the recombinant expression Effects on Catalysis (REC), the N-Tag Effects on Catalysis (TEC), and the N-Tag and Recombinant expression Effects on Catalysis (TREC) showed that the heterologous expression was more efficient than the presence of the N-terminal tag extension on the FSL.

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