Variable-temperature 13C solid-state NMR study of the molecular structure of honeybee wax and silk

Kameda, Tsunenori; Tamada, Yasushi

doi:10.1016/j.ijbiomac.2008.10.004

Cited by 51 publications

(43 citation statements)

References 21 publications

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“…This agrees with the other findings [21,22] that beeswax and Fischer-Tropsch wax both were stable as b 0 polymorph with prevailing orthorhombic subcells. A weak band spacing at 4.6 Å in beeswax XRD was observed, and it corresponds to the monoclinic subcell arrangement of the b form, which probably results from the chain packing of the free fatty acids and alcohols present in the beeswax [22]. Small, grain-like crystallites were observed in MDWAX with disordered but dense packing (Fig.…”

Section: Microstructure Of Various Waxessupporting

confidence: 93%

Textural and Physical Properties of Biorenewable “Waxes” Containing Partial Acylglycerides

Yao¹,

Wang²

2011

J Americ Oil Chem Soc

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Vegetable oil-based ''waxes'' are a promising alternative to beeswax and paraffin wax, the usual raw materials for candles and encaustic painting, because they are environmentally friendly, less expensive than beeswax and more biodegradable than paraffin. In this study, wax mixtures of mono-(MAG) and diacylglycerides (DAG) of fully hydrogenated vegetable oil were prepared at various ratios and their textural properties were compared to beeswax. Waxes having 30-40% of DAG were softer and more cohesive than those having other proportions of DAG, and their values were the closest to those of beeswax. A wax mixture of 70% MAG and 30% DAG (MDWAX) was then treated with various additives, including free fatty acid, fatty alcohol, hydroxy triacylglycerides (OHWAX), dammar resin, and acetylated monoacylglycerides (AM). The 1:1 (wt.) mixture of MDWAX and AM (referred as 50% AM) had similar plasticity to that of beeswax, and a high textural stability during one-month storage. The melting and crystallization properties of the wax containing 10% OHWAX and 90% MDWAX had close similarity to those of beeswax. The crystal form in most formulated waxes was b 0 as determined by X-ray diffraction. However, the 50% AM wax had a and b polymorphs in equal proportions and the MDWAX had only b form crystals. The crystallinity of all formulated waxes was lower than those of beeswax and paraffin. Polarized light microscopy images revealed that the microstructures of formulated waxes were different from that of beeswax. For sensory evaluation, the order of the surface buffability was determined as MDWAX?10% Dammar \ MDWAX \ MDWAX?50% AM \ paraffin \ beeswax.

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Section: Microstructure Of Various Waxessupporting

confidence: 93%

Textural and Physical Properties of Biorenewable “Waxes” Containing Partial Acylglycerides

Yao¹,

Wang²

2011

J Americ Oil Chem Soc

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“…16 We believe that the Ala-rich domain adopts an a-helical conformation, whereas Ser tends to be b-sheet stabilizing. 8 However, to date, we have yet to adequately demonstrate the absence of a-helical conformation in the Ser-rich domain. Even if no coiled-coils exist in the Ser-rich domain, the existence of a-helical conformations without a coiled-coil structure in the Ser-rich domains cannot be discounted.…”

Section: Introductionmentioning

confidence: 96%

“…[2][3][4] The structure of hornet silk has been reported in our recent studies. [5][6][7][8][9][10][11][12] The amino-acid sequences of six types of hornet silk proteins of Vespa simillima xanthoptera Cameron have been determined. 5,6,10 Of these six proteins, four are major and have similar characteristics.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the fraction of alanine residues in an α-helical conformation in hornet silk using solid-state NMR

Kameda

2012

Polym J

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Here, we demonstrate the first successful isotope labeling of Ala carbons in hornet silk produced by the larvae of Vespa (Vespinae, Vespidae) mandarinia. This labeled hornet silk was examined by high-resolution 13 C solid-state NMR, and it was found that the fraction of Ala residues in a-helical conformations compared with Ala residues in the overall conformation of hornet silk can be quantitatively determined from Ala C a NMR peaks. The value for this a-helical Ala fraction is close to that of the fraction of Ala residues in coiled-coil structures estimated in the four major hornet silk proteins by coiled-coil prediction analysis. This result indicates that most of the Ala residues in a-helices occur in those a-helices with a coiled-coil structure, and that the number of Ala residues in a-helices without a coiled-coil structure is small. Moreover, coiled-coil prediction analysis indicated that the potential coiled-coil domains are located only in the central portion of the protein chains of the major hornet silk proteins. From these results, we confirmed that the a-helical conformation mostly forms in the central portion of the hornet silk chains, whereas the ends of the protein chains are nearly devoid of a-helical structure. We deduce that the ends of the protein chains would preferentially adopt a b-sheet conformation.

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“…Beeswax is a material that consists of a mixture of several compounds mainly palmitate, palmitoleate, and oleate esters of long-chain (30-32 carbons) aliphatic alcohols [15,16]. Concerning its chemistry, an approximate chemical formula for beeswax is reported to be C15H31COOC30H61.…”

Section: Introductionmentioning

confidence: 99%

“…Different chemical, physical and structural properties of the beeswax-colophony green blend, including their crystal structure and complex phase diagrams, have been investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR) which are not in the scope of this work [15,16,21,22]. This study investigates the electrochemical and microbiological properties of beeswax-colophony green mixture as a proposed coating for drinking water storage tanks.…”

Section: Introductionmentioning

confidence: 99%

Beeswax-Colophony Blend: A Novel Green Organic Coating for Protection of Steel Drinking Water Storage Tanks

Abdikheibari

Parvizi

Moayed

et al. 2015

Metals

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Beeswax-colophony blend is mainly used as a sealant mixture for preservation applications. The beeswax itself, however, has had a long way in history taking part in conservation processes including mummification. In this research, this blend was used as a protective coating for drinking water distribution tanks. Initially, a layer with 400 μm thickness was applied on a sand blasted mild steel plate. The long-term electrochemical behavior of the coating was investigated by open circuit potential (OCP) and electrochemical microbiological characteristics of the coating, microbial and chemical examinations were performed on drinking water samples that had been in contact with the coating. Furthermore, its behavior in an up-flow anaerobic sludge blanket reactor (UASBR) in a wastewater treatment plant was investigated using the scanning electron microscopy (SEM) technique. Regarding the consistency of experimental results, it was concluded that this proposed recyclable blend could be considered as a novel green organic coating and also a good corrosion barrier even in aggressive environments. OPEN ACCESSMetals 2015, 5 1646

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Variable-temperature 13C solid-state NMR study of the molecular structure of honeybee wax and silk

Cited by 51 publications

References 21 publications

Textural and Physical Properties of Biorenewable “Waxes” Containing Partial Acylglycerides

Textural and Physical Properties of Biorenewable “Waxes” Containing Partial Acylglycerides

Quantifying the fraction of alanine residues in an α-helical conformation in hornet silk using solid-state NMR

Beeswax-Colophony Blend: A Novel Green Organic Coating for Protection of Steel Drinking Water Storage Tanks

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