Showing papers on "Lipase published in 2007"
TL;DR: It was found, using a batch system, that enzyme inhibition caused by undissolved methanol was eliminated by adding t-butanol to the reaction medium, which also gave a noticeable increase of reaction rate and ester yield.
461 citations
TL;DR: The results showed that the higher the enzyme concentration, the more accentuated was the inhibition of methane production and the process was able to recover from the inhibition.
411 citations
TL;DR: In this article, a comparison between conventional processes and enzymatic processes and different possible feedstocks for biodiesel production is presented, and possible ways to overcome the problems facing the use of lipase are described.
Abstract: Biodiesel, defined as monoalkyl fatty acid ester (preferentially methyl and ethyl esters), represents a promising alternative fuel for use in compression-ignition (diesel) engines. Biodiesel fuel comes from renewable sources as it is plant- not petroleum-derived and as such it is biodegradable and less toxic. In addition, relative to conventional diesel, its combustion products have reduced levels of particulates, carbon oxides, sulphur oxides and, under some conditions, nitrogen oxides. Enzymatic production of biodiesel has been proposed to overcome the drawbacks of the conventional chemically catalyzed processes. The main obstacle facing full exploitation of the enzyme, lipase, potential is its cost. Therefore, reuse of lipase is essential from the economic point of view, which can be achieved by using the lipase in immobilized form. In addition, immobilized lipase displays improved stability and activity. Common immobilization techniques include attachment to solid supports and entrapment within the matrix of a polymer. This article presents a comparison between conventional processes and enzymatic processes and different possible feedstocks for biodiesel production. In addition, possible ways to overcome the problems facing the use of lipase are described. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd
368 citations
TL;DR: In this article, the monoethyl esters of the long chain fatty acids (biodiesel) were prepared by alcoholysis of Jatropha oil, a non-edible oil, by a lipase.
334 citations
TL;DR: It proved that tea polyphenols were capable of binding and precipitating protein, suggesting a potential ability of TP to denature digestive enzymes, suggesting that TP might possess antinutritional properties.
319 citations
TL;DR: The relative activity of lipase could be well maintained over twelve repeated cycles with ethyl acetate while it reached to zero by 6th cycle when ethanol was used as an acyl acceptor and reusability of the lipase over repeated cycles in interesterification and ethanolysis was investigated.
268 citations
Journal Article•
TL;DR: The present article extends the frontier of lipase technology towards food processing applications and discusses the important characteristics of lipases and its sources.
Abstract: Lipases are the most pliable biocatalyst and bring about a wide range of bioconversion reactions, such as hydrolysis, interesterification, esterification, alcoholysis, acidolysis and aminolysis. Lipases can act on a variety of substrates including natural oils, synthetic triglycerides and esters of fatty acids. They are resistant to solvents and are exploited in a broad spectrum of biotechnological applications. Lipase catalyzed transesterification, hydrolysis and esterification are the important class of reactions for food technology applications in fats and oil industry, dairy industry, pharmaceuticals and bakery industry. Lipases are very peculiar as they hydrolyse fats into fatty acids and glycerol at the water-lipid interface and can reverse the reaction in non-aqueous media. Novel biotechnological applications, like biopolymer synthesis, biodiesel production, treatment of fat-containing waste effluents, enantiopure synthesis of pharmaceuticals and nutraceutical agents, have been established successfully. The present article extends the frontier of lipase technology towards food processing applications and discusses the important characteristics of lipases and its sources. Various methods of lipase immobilization for food technology applications, various assay methods for lipase, production of lipase by submerged and solid state fermentation strategies, and various purification methods available have been discussed in detail.
255 citations
TL;DR: In this article, a chitosan nanofibrous membrane with stabilized morphology was used for enzyme immobilization and the results showed that the observed lipase loading on this membrane was up to 63.6 mg/g and activity retention of the immobilized lipase was 49.8% under the optimum condition.
238 citations
TL;DR: In this paper, the power of transcriptional profiling to uncover novel PPARα-regulated genes and pathways in liver was illustrated, using an in silico screening approach, one or more PPAR response elements were identified in each of these genes.
Abstract: PPARα is a ligand-activated transcription factor involved in the regulation of nutrient metabolism and inflammation. Although much is already known about the function of PPARα in hepatic lipid metabolism, many PPARα-dependent pathways and genes have yet to be discovered. In order to obtain an overview of PPARα-regulated genes relevant to lipid metabolism, and to probe for novel candidate PPARα target genes, livers from several animal studies in which PPARα was activated and/or disabled were analyzed by Affymetrix GeneChips. Numerous novel PPARα-regulated genes relevant to lipid metabolism were identified. Out of this set of genes, eight genes were singled out for study of PPARα-dependent regulation in mouse liver and in mouse, rat, and human primary hepatocytes, including thioredoxin interacting protein (Txnip), electron-transferring-flavoprotein β polypeptide (Etfb), electron-transferring-flavoprotein dehydrogenase (Etfdh), phosphatidylcholine transfer protein (Pctp), endothelial lipase (EL, Lipg), adipose triglyceride lipase (Pnpla2), hormone-sensitive lipase (HSL, Lipe), and monoglyceride lipase (Mgll). Using an in silico screening approach, one or more PPAR response elements (PPREs) were identified in each of these genes. Regulation of Pnpla2, Lipe, and Mgll, which are involved in triglyceride hydrolysis, was studied under conditions of elevated hepatic lipids. In wild-type mice fed a high fat diet, the decrease in hepatic lipids following treatment with the PPARα agonist Wy14643 was paralleled by significant up-regulation of Pnpla2, Lipe, and Mgll, suggesting that induction of triglyceride hydrolysis may contribute to the anti-steatotic role of PPARα. Our study illustrates the power of transcriptional profiling to uncover novel PPARα-regulated genes and pathways in liver.
210 citations
TL;DR: It is demonstrated that HMMS can be efficiently employed as host materials for enzyme immobilization leading to highly enhanced stability of the immobilized enzymes with high enzyme loading and activity.
Abstract: α-chymotrypsin (CT) and lipase (LP) were immobilized in hierarchically-ordered mesocellular mesoporous silica (HMMS) in a simple but effective way for the enzyme stabilization, which was achieved by the enzyme adsorption followed by glutaraldehyde (GA) crosslinking. This resulted in the formation of nanometer scale crosslinked enzyme aggregates (CLEAs) entrapped in the mesocellular pores of HMMS (37 nm), which did not leach out of HMMS through narrow mesoporous channels (13 nm). CLEA of α-chymotrypsin (CLEA-CT) in HMMS showed a high enzyme loading capacity and significantly increased enzyme stability. No activity decrease of CLEA-CT was observed for 2 weeks under even rigorously shaking condition, while adsorbed CT in HMMS and free CT showed a rapid inactivation due to the enzyme leaching and presumably autolysis, respectively. With the CLEA-CT in HMMS, however, there was no tryptic digestion observed suggesting that the CLEA-CT is not susceptible to autolysis. Moreover, CLEA of lipase (CLEA-LP) in HMMS retained 30% specific activity of free lipase with greatly enhanced stability. This work demonstrates that HMMS can be efficiently employed as host materials for enzyme immobilization leading to highly enhanced stability of the immobilized enzymes with high enzyme loading and activity. Biotechnol. Bioeng. 2007;96: 210–218. © 2006 Wiley Periodicals, Inc.
193 citations
TL;DR: A commercial preparation of lipase from Pseudomonas cepacia was used as a catalyst for converting this oil into ethyl esters, and modified biocatalyst formulations called cross-linked enzyme aggregates (CLEAs) and protein-coated microcrystals (PCMCs) obtained the best results.
Abstract: The oil from Madhuca indica has a high free fatty acid content, and hence, it is difficult to convert it into biodiesel by using a chemical catalyst. In this work, a commercial preparation of lipase from Pseudomonas cepacia was used as a catalyst for converting this oil into ethyl esters. Solvent-free media were used for this process. The process optimization consisted of varying parameters, such as water content in the reaction medium and salt present during the drying of lipase prior to its use as powder. The lipase immobilized on accurel gave 96% conversion in 6 h. The best results were obtained using modified biocatalyst formulations, which are called cross-linked enzyme aggregates (CLEAs) and protein-coated microcrystals (PCMCs). While free enzyme powder after process optimization gave 98% conversion in 6 h using 50 mg of lipase, CLEAs gave 92% conversion in 2.5 h (using an equivalent of 50 mg of enzyme) and PCMCs gave 99% conversion in 2.5 h using the same amount of enzyme. In the case of PCMCs, 99%...
TL;DR: In this article, hydrotalcite and four different types of zeolites were used as metarial metarial agents, and the size and type of the zeolite particles did not affect the amount of protein adsorbed.
TL;DR: The resulting glycerol carbonate from 60 °C reaction has shown the low enantiomeric excess (13% ee) as configuration of (R)-enantiomer.
Abstract: Glycerol carbonate is a key multifunctional compound employed as solvent, additive, monomer, and chemical intermediate. Enzymatic synthesis of glycerol carbonate from renewable starting materials (glycerol and dimethyl carbonate) was successfully achieved by immobilized lipase from Candida antarctica (CALB, Novozym 435). Addition of molecular sieves as scavenger for the removal of methanol, which was generated from dimethyl carbonate during the reaction, accelerated a reaction rate. After the optimization, the equimolar use of glycerol and dimethyl carbonate in the Novozym 435-catalyzed reaction yielded a glycerol carbonate with almost quantitative yield. The resulting glycerol carbonate from 60 °C reaction has shown the low enantiomeric excess (13% ee) as configuration of (R)-enantiomer.
Patent•
22 Jan 2007TL;DR: In this article, a bleach catalyst that is capable of accepting an oxygen atom from a peroxy acid and transferring the oxygen atom to an oxidizeable substrate is described. But the present paper relates to a composition comprising: (i) a lipase; and (ii) a bleach catalyzer.
Abstract: The present invention relates to a composition comprising: (i) a lipase; and (ii) a bleach catalyst that is capable of accepting an oxygen atom from a peroxyacid and transferring the oxygen atom to an oxidizeable substrate.
TL;DR: In this article, the effect of temperature, water content, enzyme amount, solvent and three-step methanolysis on biodiesel production from lard was investigated using Candida sp. 99-125, and the optimal conditions for processing 1 g of lard were: 0.2 g immobilized lipase, 8 ml n-hexane as solvent, 20% water based on the fat weight, temperature 40 °C, and three step addition of methanol.
TL;DR: The data demonstrate that ATGL is important for efficient TG lipase activity in humans, and demonstrate reduced ATGL protein expression and TG lip enzyme activity despite increased mRNA expression of ATGL and other novel lipolytic enzymes in obesity.
Abstract: We have investigated the gene and protein expression of adipose triglyceride lipase (ATGL) and triglyceride (TG) lipase activity from subcutaneous and visceral adipose tissue of lean and obese subjects. Visceral and subcutaneous adipose tissue was obtained from 16 age-matched lean and obese subjects during abdominal surgery. Tissues were analyzed for mRNA expression of lipolytic enzymes by real-time quantitative PCR. ATGL protein content was assessed by Western blot and TG lipase activity by radiometric assessment. Subcutaneous and visceral adipose tissue of obese subjects had elevated mRNA expression of PNPLA2 (ATGL) and other lipases including PNPLA3, PNPLA4, CES1, and LYPLAL1 (P < 0.05). Surprisingly, ATGL protein expression and TG lipase activity were reduced in subcutaneous adipose tissue of obese subjects. Immunoprecipitation of ATGL reduced total TG lipase activity in adipose lysates by 70% in obese and 83% in lean subjects. No significant differences in the ATGL activator CGI-58 mRNA levels (ABHD5) were associated with obesity. These data demonstrate that ATGL is important for efficient TG lipase activity in humans. They also demonstrate reduced ATGL protein expression and TG lipase activity despite increased mRNA expression of ATGL and other novel lipolytic enzymes in obesity. The lack of correlation between ATGL protein content and in vitro TG lipase activity indicates that small decrements in ATGL protein expression are not responsible for the reduction in TG lipase activity observed here in obesity, and that posttranslational modifications may be important.
TL;DR: This lipase immobilization method shows the best performance among various immobilized lipase systems using the same source of lipase and substrate when considering protein loading, activity retention, and kinetic parameters.
Abstract: Polyacrylonitrile (PAN) nanofibers could be fabricated by electrospinning with fiber diameter in the range of 150–300 nm, providing huge surface area for enzyme immobilization and catalytic reactions. Lipase from Candida rugosa was covalently immobilized onto PAN nanofibers by amidination reaction. Aggregates of enzyme molecules were found on nanofiber surface from field emission scanning electron microscopy and covalent bond formation between enzyme molecule and the nanofiber was confirmed from FTIR measurements. After 5 min activation and 60 min reaction with enzyme-containing solution, the protein loading efficiency was quantitative and the activity retention of the immobilized lipase was 81% that of free enzyme. The mechanical strength of the NFM improved after lipase immobilization where tensile stress at break and Young's modulus were almost doubled. The immobilized lipase retained >95% of its initial activity when stored in buffer at 30 °C for 20 days, whereas free lipase lost 80% of its initial activity. The immobilized lipase still retained 70% of its specific activity after 10 repeated batches of reaction. This lipase immobilization method shows the best performance among various immobilized lipase systems using the same source of lipase and substrate when considering protein loading, activity retention, and kinetic parameters.
TL;DR: The bacteria that could grow on media containing olive mill wastewater (OMW) were isolated and their lipase production capacities were investigated, and the strain possessing the highest lipase activity among 17 strains grown on tributyrin agar medium was identified as Bacillus sp.
TL;DR: An overall 12-fold enhanced production was achieved after medium optimization following the "one-variable-at-a-time" and the statistical approaches after alkaline lipase production was produced within 15 h of growth in a 14 L bioreactor.
TL;DR: An alignment of amino acid sequences of the pancreatic lipase gene family members revealed two molecular characteristics of PLA1s in the two surface loops that appear to be involved in the ligand recognition.
TL;DR: It is found that norepinephrine-induced lipolysis was positively correlated with HSL protein levels (P < 0.0001) but not with ATGL protein, and ATGL expression, unlike HSL, is not influenced by obesity or PCOS.
Abstract: Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) regulate adipocyte lipolysis in rodents. The purpose of this study was to compare the roles of these lipases for lipolysis in h...
TL;DR: Analysis of the initial rate data showed that reaction followed a Ping-Pong Bi-Bi mechanism with inhibition by acetic anhydride, and equation predictions and experimental reaction rate values matched very well at conditions where acetic acid concentration in the medium was low.
TL;DR: The enzyme source showed strong influence on the transesterification yields, and the best performance was attained with the lipase from Pseudomonas fluorescens that reached almost full conversion (≅98%) in less than 24 h of reaction.
Abstract: This work deals with the transesterification of palm oil with ethanol in a solvent free system using lipase from different sources (Thermomyces lanuginosus, Pseudomonas fluorescens, Burkholderia cepacia, Penicillium camembertii, and Candida antarctica, porcine pancreatic) immobilized on hybrid support polysiloxane–poly(vinyl alcohol). This is an exceptional option for the Brazilian biodiesel production, because both palm oil and ethanol are readily available in the country. The enzyme source showed strong influence on the transesterification yields, and the best performance was attained with the lipase from Pseudomonas fluorescens that reached almost full conversion (≅98 %) in less than 24 h of reaction. The purified product (biodiesel) was straw yellow in color and essentially odorless. Purity of the fatty acid ethyl ester was found to be high having no glycerol bound as verified by NMR 13C (APT, attached proton test). In addition, the other properties such as low water content (0.02%), specific gravity ...
TL;DR: It is shown that C. parapsilosis-secreted lipase is involved in disease pathogenesis and this efficient system for targeted gene deletion holds great promise for rapidly enhancing knowledge of the biology and virulence of this increasingly common invasive fungal pathogen.
Abstract: Candida parapsilosis is a major cause of human disease, yet little is known about the pathogen’s virulence. We have developed an efficient gene deletion system for C. parapsilosis based on the repeated use of the dominant nourseothricin resistance marker (caSAT1) and its subsequent deletion by FLP-mediated, site-specific recombination. Using this technique, we deleted the lipase locus in the C. parapsilosis genome consisting of adjacent genes CpLIP1 and CpLIP2. Additionally we reconstructed the CpLIP2 gene, which restored lipase activity. Lipolytic activity was absent in the null mutants, whereas the WT, heterozygous, and reconstructed mutants showed similar lipase production. Biofilm formation was inhibited with lipase-negative mutants and their growth was significantly reduced in lipid-rich media. The knockout mutants were more efficiently ingested and killed by J774.16 and RAW 264.7 macrophage-like cells. Additionally, the lipase-negative mutants were significantly less virulent in infection models that involve inoculation of reconstituted human oral epithelium or murine intraperitoneal challenge. These studies represent what we believe to be the first targeted disruption of a gene in C. parapsilosis and show that C. parapsilosis–secreted lipase is involved in disease pathogenesis. This efficient system for targeted gene deletion holds great promise for rapidly enhancing our knowledge of the biology and virulence of this increasingly common invasive fungal pathogen.
TL;DR: The results imply that temperature control and careful dosage of hydrogen peroxide would be essential in an industrial chemo-enzymatic process.
TL;DR: It is reported that lipase activity was detected in four species of Malassezia, including M. globosa, the first step in a molecular description of lipid metabolism on the scalp, ultimately leading toward a test of its role in D/SD etiology.
TL;DR: An extracellular lipase from Yarrowia lipolytica (YlLip2) has been purified by ion exchange chromatography on Q sepharose FF, followed by hydrophobic interaction chromatography in order to identify the glycosylated protein and showed a preference for long chain fatty acid methyl esters.
TL;DR: Yeast transformation efficiency and expression cassette insertion were increased by constructing a strain containing a zeta docking platform for targeted integration into the genome and the coefficient of variance of the full process was reduced.
TL;DR: Numerical models successfully simulated both conversion of substrate fat into biomass and production and subsequent hydrolysis of extra-cellular lipase and presented a satisfactory predictive ability verifying the potential for single-cell protein and lipase production by Yarrowia lipolytica ACA-DC 50109.
TL;DR: The lipolytic activity of pancreatic extracts and human pancreatic juice on Labrasol(R) is therefore mainly due to the combined action of CEH and PLRP2.