scholarly journals Enzyme–Catalysed Synthesis of Palm-Based Wax Esters-A Kinetic Study

2012 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Erin Ryantin Gunawan ◽  
Mahiran Basri ◽  
Dedy Suhendra
Keyword(s):  
Palm Oil ◽  
Oleyl Alcohol ◽  
Wax Esters ◽  
Alcoholysis Reaction ◽  
Ping Pong ◽  
Wide Range ◽  
Chain Lengths ◽  
Menten Constant ◽  
Long Chain ◽  
Mechanism Of The Reaction

Wax esters are long chain esters that are derived from fatty acids and alcohols with chain lengths of 12 carbons or more. Wax esters havea wide range of application in industrial especially in cosmetics. The present work focuses on the synthesis of wax esters by alcoholysisreaction from palm oil and oleyl alcohol in hexane by lipase from Rhizomucor meihei (Lipozyme IM). Effect of various concentrations ofpalm oil and oleyl alcohol were studied to deduce the kinetics and mechanism of the reaction. The alcoholysis reaction followed Michaelis-Menten kinetics. The reaction follows a Ping-pong Bi-Bi mechanism. The maximum rate was estimated to be 6 x 10 -3 mmol/h. mg catalystand the Michaelis-Menten constant for palm oil and oleyl alcohol were 4.145 M and 6.120 M, respectively.

Composition of the Epicuticular Wax Esters of Picea abies (L.) Karst

1995 ◽  
Vol 50 (1-2) ◽  
pp. 11-14 ◽  
Author(s):  
Peter Sümmchen ◽  
Claus Markstädter ◽  
Otto Wienhaus
Keyword(s):  
Fatty Acids ◽  
Picea Abies ◽  
Methyl Esters ◽  
Wax Esters ◽  
Minor Components ◽  
Alkyl Esters ◽  
New Class ◽  
Gas Chromatography Mass Spectroscopy ◽  
Chain Lengths ◽  
Long Chain

Abstract The long-chain alkyl esters homologues of the cuticular needle wax of Picea abies consist of a series of isomers, which are formed by different n-fatty acids and n-alkanols of various chain lengths. Even-numbered esters are dominating. Methyl esters range from C27 to C37, even-numbered esters are only minor components. Furthermore, a new class of homologue wax esters was isolated. Examination by gas chromatography, mass spectroscopy and chemi­cal studies resulted in identification of pentenyl esters of triacontanoic, dotriacontanoic, tetratriacontanoic and hexatriacontanoic acid.

scholarly journals Burkholderia thailandensis E264 as a promising safe rhamnolipids’ producer towards a sustainable valorization of grape marcs and olive mill pomace

2021 ◽  
Author(s):  
Alif Chebbi ◽  
Massimiliano Tazzari ◽  
Cristiana Rizzi ◽  
Franco Hernan Gomez Tovar ◽  
Sara Villa ◽  
...  
Keyword(s):  
Energy Source ◽  
Olive Oil ◽  
Low Cost ◽  
Carbon Sources ◽  
Burkholderia Thailandensis ◽  
Rhamnolipid Production ◽  
Key Points ◽  
Wide Range ◽  
Long Chain ◽  
Olive Mill

Abstract Within the circular economy framework, our study aims to assess the rhamnolipid production from winery and olive oil residues as low-cost carbon sources by nonpathogenic strains. After evaluating various agricultural residues from those two sectors, Burkholderia thailandensis E264 was found to use the raw soluble fraction of nonfermented (white) grape marcs (NF), as the sole carbon and energy source, and simultaneously, reducing the surface tension to around 35 mN/m. Interestingly, this strain showed a rhamnolipid production up to 1070 mg/L (13.37 mg/g of NF), with a higher purity, on those grape marcs, predominately Rha-Rha C14-C14, in MSM medium. On olive oil residues, the rhamnolipid yield of using olive mill pomace (OMP) at 2% (w/v) was around 300 mg/L (15 mg/g of OMP) with a similar CMC of 500 mg/L. To the best of our knowledge, our study indicated for the first time that a nonpathogenic bacterium is able to produce long-chain rhamnolipids in MSM medium supplemented with winery residues, as sole carbon and energy source. Key points • Winery and olive oil residues are used for producing long-chain rhamnolipids (RLs). • Both higher RL yields and purity were obtained on nonfermented grape marcs as substrates. • Long-chain RLs revealed stabilities over a wide range of pH, temperatures, and salinities

Mechanistic Study on Gold(I)-Catalyzed Unsaturated Spiroketalization Reaction

2022 ◽  
Vol 19 ◽  
Author(s):  
Kamlesh Sharma
Keyword(s):  
Activation Barrier ◽  
Ring Formation ◽  
Hydroxyl Group ◽  
Mechanistic Study ◽  
Protecting Group ◽  
Wide Range ◽  
Oxocarbenium Ion ◽  
Metal Catalyzed ◽  
Insight Into ◽  
Mechanism Of The Reaction

Abstract: The mechanism of metal-catalyzed spiroketalization of propargyl acetonide is explored by employing DFT with the B3LYP/6-31+G(d) method. Acetonide is used as a regioselective regulator in the formation of monounsaturated spiroketal. The energies of transition states, intermediates, reactants and products are calculated to provide new insight into the mechanism of the reaction. The energetic features, validation of the observed trends in regioselectivity are conferred in terms of electronic indices via FMO analysis. The presence of acetonide facilitates a stepwise spiroketalization as it masks the competing nucleophile, and thus hydroxyl group present, exclusively acts as a nucleophile. The vinyl gold intermediate 3 is formed from 2 via activation barrier TS1. This is the first ring formation, which is 6-exo-dig cyclization. The intermediate 3 is converted into allenyl ether 4, which isomerizes to the intermediate oxocarbenium ion 5 via activation barrier TS2. The intermediate 5 cyclizes to 6 via TS3. This is the second ring formation. The intermediate 6 on protodeauration turns into 6,6-monounsaturated spiroketal 7. It is concluded that acetonide as a protecting group serves the purpose, and thus a wide range of spiroketals can be prepared, regioselectivity.

The Use of N-alkanes for Estimating Intake and Passage Rate in Horses

1996 ◽  
Vol 1996 ◽  
pp. 98-98
Author(s):  
B M L McLean ◽  
R W Mayes ◽  
F D DeB Hovell
Keyword(s):  
Recent Work ◽  
Chain Length ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Passage Rate ◽  
Forage Crops ◽  
Carbon Chains ◽  
Naturally Occurring ◽  
Chain Lengths ◽  
Long Chain

Alkanes occur naturally in all plants, although forage crops tend to have higher alkane contents than cereals. N-alkanes have odd-numbered carbon chains. They are ideal for use as markers in feed trials, because, they are inert, indigestible and naturally occurring, and can be recovered in animal faeces. Synthetic alkanes (even-numbered carbon chains) are available commercially and can also used as external markers. Dove and Mayes (1991) cite evidence indicating that faecal recovery of alkanes in ruminants increases with increasing carbon-chain length. Thus the alkane “pairs” (e.g. C35 & C36, and C32 & C33) are used in calculating intake and digestibility because they are long chain and adjacent to each other. However, recent work by Cuddeford and Mayes (unpublished) has found that in horses the faecal recovery rates are similar regardless of chain lengths.

Antibacterial Effects of Long-Chain Polyphosphates on Selected Spoilage and Pathogenic Bacteria

2008 ◽  
Vol 71 (7) ◽  
pp. 1401-1405 ◽  
Author(s):  
JEREMY A. OBRITSCH ◽  
DOJIN RYU ◽  
LUCINA E. LAMPILA ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Food Industry ◽  
Pathogenic Bacteria ◽  
Antimicrobial Activities ◽  
Lag Phase ◽  
E Coli ◽  
Inhibition Of Growth ◽  
K 12 ◽  
Chain Lengths ◽  
And Staphylococcus Aureus ◽  
Long Chain

The antimicrobial activities of four long-chain food-grade polyphosphates were studied at concentrations allowed in the food industry (<5,000 ppm) in defined basal media by determining the inhibition of growth of three gram-negative and four gram-positive spoilage and pathogenic bacteria. Both generation time and lag phase of Escherichia coli K-12, E. coli O157: H7, and Salmonella Typhimurium were increased with all of the polyphosphates tested. Bacillus subtilis and Staphylococcus aureus were more sensitive to polyphosphates, but not in all cases, with multiphased growth. The growth of Lactobacillus plantarum was inhibited by polyphosphates at concentrations above 750 ppm, but the lag time of Listeria monocytogenes was shortened by the presence of polyphosphates. No single polyphosphate was maximally inhibitory against all bacteria. Polyphosphates with chain lengths of 12 to 15 were significantly different from those with chain lengths of 18 to 21 depending on the organism and concentrations of polyphosphate used. Overall, higher polyphosphate concentrations resulted in greater inhibition of bacterial growth.

scholarly journals Multiple mutagenesis of non-universal serine codons of the Candida rugosa LIP2 gene and biochemical characterization of purified recombinant LIP2 lipase overexpressed in Pichia pastoris

2002 ◽  
Vol 366 (2) ◽  
pp. 603-611 ◽  
Author(s):  
Guan-Chiun LEE ◽  
Li-Chiun LEE ◽  
Vasyl SAVA ◽  
Jei-Fu SHAW
Keyword(s):  
Pichia Pastoris ◽  
Biochemical Characterization ◽  
Candida Rugosa ◽  
Residual Activity ◽  
Site Directed Mutagenesis ◽  
Overlap Extension ◽  
Chain Lengths ◽  
Serine Codons ◽  
Long Chain ◽  
Lip2 Lipase

The 17 non-universal serine codons (CTG) in the Candida rugosa LIP2 gene have been converted into universal serine codons (TCT) by overlap extension PCR-based multiple site-directed mutagenesis. An active recombinant LIP2 lipase was overexpressed in Pichia pastoris and secreted into the culture medium. The recombinant LIP2 showed distinguishing catalytic activities when compared with recombinant LIP4 and commercial C. rugosa lipase. The purified enzyme showed optimum activity at pH7 and a broad temperature optimum in the range 30–50°C. The enzyme retained 80% of residual activity after being heated at 70°C for 10min. Recombinant LIP2 demonstrated high esterase activity towards long-chain (C12–C16) p-nitrophenyl esters. Tributyrin was the preferred substrate among all triacylglycerols tested for lipolysis. Among cholesteryl esters, LIP2 showed highest lipolytic activity towards cholesteryl laurate. The esterification of myristic acid with alcohols of various chain lengths showed that the long-chain n-octadecanol (C18) was the preferred substrate. In contrast, the esterification of n-propanol with fatty acids of various chain lengths showed that the short-chain butyric acid was the best substrate. From comparative modelling analysis, it appears that several amino acid substitutions resulting in greater hydrophobicity in the substrate-binding site might play an important role in the substrate specificity of LIP2.

Abstract 16607: Age-induced Endoplasmic Reticulum Stress in the Heart: Role of Increased Very Long-chain Ceramides

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Qun Chen ◽  
Anna Kovilakath ◽  
Jeremy Allegood ◽  
Lauren A Cowart ◽  
Edward J Lesnefsky
Keyword(s):  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
Acyl Chain ◽  
Membrane Domains ◽  
Ceramide Synthase ◽  
Age Related ◽  
Chain Lengths ◽  
Endoplasm Reticulum ◽  
Long Chain

Introduction: Mitochondrial function is impaired in aged hearts. Increased endoplasm reticulum (ER) stress contributes to the mitochondrial dysfunction observed during aging. Ceramides (CRMD) are sphingolipid metabolites that contribute key roles in cell signaling. Increased CRMD can lead to ER stress. Ceramide synthase enzymes (CerS) generate chain length specific CRMD with the CerS isoform 2 (Cers2) forming very long chain CRMD of ≥ 20 carbon acyl chain lengths. Hypothesis: An increase in CRMD content during aging contributes to age-related ER stress. Methods: Male mice (3, 18, 24 mo.) from the NIA colony were studied. Cardiac mitochondria (MITO), mitochondrial associated membranes (MAM), and ER were isolated from mouse hearts. CRMD content was measured using LC-MS. The contents of CerS enzymes were measured by immunoblotting in myocardial homogenates. Results: ER stress increased progressively during aging with increased contents of cleaved ATF6 and CHOP, indicators of increased ER stress, evident at 18 and 24 mo. (Panel A) (all data mean±SEM; *p<0.05 vs. 3 mo., † p<0.05 vs. 18 mo.). Aging increased very long-chain CRMD (≥C20) in ER (Panel B) at 18 and 24 mo. Similar CRMD trends were observed MAM (Panel C), shared membrane domains where ER and MITO interact. The content of CerS2 was increased at 24 mo. compared to 3 mo. (Panel D, n=4 each age). In contrast, the contents of CerS isoforms 4 and 5, that generate shorter chain CRMD (<C20) were unchanged (not shown). CRMD contents in MITO were unaltered with age (not shown). Thus, increased generation of very long chain CRMD in the ER is the likely mechanism of increased ER stress in the aged heart. Conclusion: Aging increased ER CRMD content by enhancing the formation of very long chain CRMD in ER by an increase in CerS2 content, concomitant with the onset of ER stress. The increase in age-induced ER stress, in turn, leads to mitochondrial dysfunction in the aged heart.

Absorption of short-chain to long-chain perfluoroalkyl substances using swellable organically modified silica

2019 ◽  
Vol 5 (11) ◽  
pp. 1854-1866 ◽  
Author(s):  
Eva K. Stebel ◽  
Kyndal A. Pike ◽  
Huan Nguyen ◽  
Heather A. Hartmann ◽  
Mattaeus J. Klonowski ◽  
...  
Keyword(s):  
Short Chain ◽  
Perfluoroalkyl Substances ◽  
Modified Silica ◽  
Wide Range ◽  
Organically Modified ◽  
Organically Modified Silica ◽  
Long Chain

Adsorbents comprising swellable organically modified silica were characterized to optimize the adsorption of a wide range of perfluoroalkyl substances from water.

Wax Esters in Fish: Absorption and Metabolism of Oleyl Alcohol in the Gourami (Trichogaster cosby)

1973 ◽  
Vol 103 (4) ◽  
pp. 600-607 ◽  
Author(s):  
D. M. Sand ◽  
C. H. Rahn ◽  
H. Schlenk
Keyword(s):  
Oleyl Alcohol ◽  
Wax Esters

Assembly of Bacterial Capsular Polysaccharides and Exopolysaccharides

2020 ◽  
Vol 74 (1) ◽  
pp. 521-543 ◽  
Author(s):  
Chris Whitfield ◽  
Samantha S. Wear ◽  
Caitlin Sande
Keyword(s):  
Structural Biology ◽  
Biomedical Applications ◽  
Capsular Polysaccharide ◽  
Strong Association ◽  
Capsular Polysaccharides ◽  
Physical Chemical ◽  
Wide Range ◽  
Bacterial Surfaces ◽  
Genomic Studies ◽  
Long Chain

Polysaccharides are dominant features of most bacterial surfaces and are displayed in different formats. Many bacteria produce abundant long-chain capsular polysaccharides, which can maintain a strong association and form a capsule structure enveloping the cell and/or take the form of exopolysaccharides that are mostly secreted into the immediate environment. These polymers afford the producing bacteria protection from a wide range of physical, chemical, and biological stresses, support biofilms, and play critical roles in interactions between bacteria and their immediate environments. Their biological and physical properties also drive a variety of industrial and biomedical applications. Despite the immense variation in capsular polysaccharide and exopolysaccharide structures, patterns are evident in strategies used for their assembly and export. This review describes recent advances in understanding those strategies, based on a wealth of biochemical investigations of select prototypes, supported by complementary insight from expanding structural biology initiatives. This provides a framework to identify and distinguish new systems emanating from genomic studies.

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