• International Journal of Industrial Entomology and Biomaterials
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• 제47권1호
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• pp.63-71
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• 2023

In this study, the structural characteristics of sericin recovered from wastewater released from the silk textile industry (Plant sericin) were comparatively analyzed with those of sericin extracted from a silkworm cocoon produced in a laboratory (Lab sericin). To prepare Plant sericin, ethanol was added to wastewater (i.e., a sericin aqueous solution) after the degumming process to remove nonprotein materials, affording a sericin precipitate. To prepare Lab sericin, nonprotein materials were removed from a silkworm cocoon and sericin was subsequently extracted from the cocoon. Lab sericin and Plant sericin exhibited similar solution viscosities, gel strengths, and crystallinity indices, indicative of the similar molecular weights (MWs) of the two sericin samples. In the case of sericin powder, Plant sericin was more crystalline than Lab sericin due to its treatment with ethanol. The findings of this study revealed that sericin recovered from industrial wastewater can be used equally as its MW is similar to that of sericin obtained through laboratory-scale extraction.

• International Journal of Industrial Entomology and Biomaterials
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• 제15권2호
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• pp.171-174
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• 2007

Sericin beads were prepared from ethanol-precipitated sericin. The addition of ethanol into hot-water extracted sericin solution induced precipitation of sericin and thereby some sericin could be fractionated. The ethanol-precipitated sericin (EpSS) had narrower molecular weight distribution than original sericin. The EpSS had mainly random coil structure with small portion of ${\beta}-sheet$ structure. With the EpSS, spherical beads could be prepared at lower concentration than with original sericin due to higher viscosity. The EpSS beads had better compressive strength than the original sericin beads and had rubber-like property. Our results suggest that EpSS is more compatible in the polymeric field, since it has better mechanical strength than original sericin.

• International Journal of Industrial Entomology and Biomaterials
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• 제27권1호
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• pp.180-184
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• 2013

Recently, silk sericin has attracted the attention of researchers owing to its useful properties as a biomaterial including 1) good wound healing and cell activities, 2) fast gelation character, and 3) high water retention property. In the present study, silk sericin was prepared using different extraction times in hot water and the effect of extraction time on the rheological properties of sericin solutions and gels was examined. It was found that the production yield of sericin increased with extraction time. The shear viscosity of sericin solutions and gels decreased with increasing extraction time due to a decrease in sericin molecular weight. When the sericin solution transformed to a gel, the viscosity increased and the shear thinning behavior was more evident. In addition, the shear stress measurements indicated that the slip between the sericin samples and the measuring plate of the rheometer was increased by the gelation of sericin. The compression strength of sericin gel could be increased remarkably (by more than 100 fold) by preparation using the freezing and thawing method.

• 한국잠사곤충학회지
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• 제40권2호
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• pp.143-149
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• 1998

For the application of silk sericin, silk sericin powders were prepared by various spray dry conditions and the characteristics of silk sericin/polyurethane mixed films were investigated. When the sericin was dried from the solution at higher inlet and outlet temperature, larger sizes of the powder particles were obtained. It was also found that inlet and outlet temperatures were important factors affecting the shape and surface characteristics of sericin power particle. The many holes and empty spaces were observed at the surface and cross section of sericin/PU mixed film. With the increase of the amount of sericin powder in the mixed films, the size and number of holes and empty spaces were increased. The thickness of sericin/PU mixed film was increased with the content of sericin powder. As the portion of sericin powder increase, the tenacity is decreased while the elongation slightly increased.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.501-519
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• 2003

Silk Sericin(SS) is a natural protein extracted from cocoon of bombix mori and shows moisturizing effect to the skin due to a number of hydroxyl groups in the structure. But its application to cosmetics is limited due to its poor solubility in water. In order to solve this drawback and expand its application to cosmetics, polyethyleneglycol(PEG) was conjugated with sericin by reacting activated polyethyleneglycol(ActPEG). Reaction site of sericin is tyrosine residue, which was determined by using $^1$H-NMR. Random coil structure of sericin was transformed to beta-sheet structure by conjugating polyethyleneglycol. It was confirmed that melting point of sericin-PEG conjugate was lowered compared to that of each sericin and PEG due to the interaction between sericin and PEG in crystalline structure. Self-assembled sericin-PEG nanoparticle was obtained by dialyzing with alcohol solution of sericin-PEG conjugate against water. The particle is spherical and has 200-400nm of size. The moisturizing ability of sericin-PEG nanoparticle was much higher than that of sericin itself. Incorporation of vitamin A into sericin-PEG nanoparticle was carried out by diafiltration method. The content of incorporated Vitamin A in sericin-PEG nanoparticle was 8.9 wt％. Releasing behaviour of vitamin A incorporated into nanoparticle was tested in phosphate buffer, pH 7.4 at 37$^{\circ}C$. and half-life of Vitamin A release was 43hrs. Sericin-PEG nanoparticle exhibited higher moisturing effect than sericin itself and distilled water, respectively. No toxicity and irritation were observed in animal tests. It can be expected that the self-assembled sericin-PEG nanoparticle can be developed for cosmetics.

• Current Research on Agriculture and Life Sciences
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• 제20권
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• pp.55-63
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• 2002

세리신 잠의 발육, 실샘 성장, 세리신 량, 혈액 아미노산 조성 등 세리신 잠의 특성을 알아보기 위하여 잠 120 과 같은 조건으로 사육하여 얻은 결과는 다음과 같다. 1. 부화율에 있어서 세리신 잠은 85%이며 잠 120 은 95%이었다. 특히 세리신 잠은 부화가 고르지 않았다. 2. 유충 기간에 있어서 세리신은 20 일 23 시간이었고, 잠 120 은 21 일 22시간이었다. 3. 실샘에 있어서 세리신 잠은 중부실샘이 대부분이며 후부 실샘의 길이는 약 2~3cm 이었고 굴곡은 없었다. 4. 세리신 잠에 있어서 상족후 나방까지의 기간은 약 12 일이었으며, 화용후 화아까지는 7 일로 대단히 짧은 특성을 보였다. 5. 고치에 있어서 세리신 잠은 이주 얇고 가벼웠으며 견충중은 2.7cg 이며 견충 비율은 3.65%이였다. 6. 세리신 (sericin protein)양에 있어서, 세리신 잠의 견충이 sericin 만 으로 구성되어 있고 잠 120 은 28%가 sericin 이었다. 세리신 잠의 견충 당 sericin 율은 잠 120 의 34.6%정도였다. 7. 혈액 아미노산의 양에 있어서 세리신 잠은 histidine, lysine, glutamic acid 가 많았으며 5 령 발육에 따른 조성의 변화에 있어서 대부분의 혈액 아미노산들은 증가하였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제33권2호
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• pp.144-148
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• 2016

Recently, silk sericin has been studied extensively for biomedical and cosmetic applications because of its unique properties, including UV resistance and wound healing ability. For use in applications, sericin is fabricated in various forms including films and gels. However, the mechanical properties of sericin are too weak. In this basic study on improving the mechanical properties of sericin, a silk sericin aqueous solution was separated into two layers by centrifugation. The solution viscosity, molecular conformation, and mechanical properties of each separation layer of the sericin were examined. Sericin from the lower layer had a higher solution viscosity and film mechanical properties (strength and strain) than that from the upper layer, implying that sericin from the lower layer had a higher molecular weight than that from the upper layer. The molecular conformation of the sericin films varied depending on the casting solvent. In aqueous solution, the sericin film from the lower layer showed a ${\beta}$-sheet conformation, whereas that from the upper layer displayed a random coil conformation. All the sericin films showed a highly ${\beta}$-sheet-crystallized state when cast in formic acid, regardless of the separation layer.

• 한국잠사곤충학회지
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• 제42권2호
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• pp.104-108
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• 2000

To hydrolyze insolule sericin the enzyme hydrolysis was used, and then obtained the results as given belows. When insoluble sericin was hydrolyzed by enzyme treatment, the solubility was best at pH 7, 60$\^{C}$ and was slightly increased both above 2 hours treatment and above 10% of enzyme concentration. As the results of electrophoresis, the distribution of molecular weight of sericin powder obtained by enzyme hydrolysis was very weak and showed in the wide range having no distinguishable band. Average degree of polymerzations (A.D.P.) of sericin hydrolyzed by enzyme were about 4.1∼6.3, average molecular weight were about 470∼730. The whiteness of the sericin powder obtained by enzyme hydrolysis was high and increased slightly with higher treatment concentration of enzyme. As the results of amino acid analysis, the amino acid analysis, the amino acid composition of the sericin powder from the enzyme treatment were similar to which located at near 230$\^{C}$ and 320$\^{C}$. The peak of near 230$\^{C}$ could not been found in the sericin powder obtained by enzyme hydrolysis.

• 한국염색가공학회지
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• 제21권1호
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• pp.67-72
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• 2009

To investigate the strong and effective sericin fixing agents and conditions, raw silk fibers were treated with the mixtures of urea-formalin, thiourea-formalin and melamine-formalin as sericin fixing agents, respectively. And the treated raw silk fibers were degummed by the degumming liquors of alkaline detergent and sodium carbonate to confirm the hardness of sericin fixation. The weight of raw silk fibers was decreased in the process of sericin fixation treating at 80$^{\circ}C$ for 60min. The effective sericin fixation was obtained by treating at $60{\sim}80^{\circ}C$ for 15min with the mixture of melamine and formalin. The mixture of melamine and formalin showed an outstanding ability of sericin fixation because the three amino groups of melamine were able to cross-link the hydroxy amino acids of sericin such as serine with the assistance of formalin.

• 한국잠사곤충학회지
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• 제30권1호
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• pp.33-39
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• 1988

본 시험은 자외선에 의해 구분된 황형광색견(Y.F.C)와 자형광색견(V.F.C)의 견층 sericin이 열수에 대한 성질과 견층 sericin 수용액의 물리적 성질 차이를 조사하고 제사성적에 미치는 영향을 검토한 결과를 요약하면 다음과 같다. 1. 용해온도에 따른 sericin의 용해성은 낮은 온도에서보다 높은 온도에서 Y.F.C와 V.F.C간의 차가 켰다. 2. 용해시간에 따른 sericin의 용해성은 Y.F.C 및 V.F.C 모두 비슷한 경향을 나타냈으나 Y.F.C가 V.F.C. 보다 용해성이 좋았다. 3. 초기 sericin 용해성을 도시하면 용해도가 다른 4개 부분으로 구분할 수 있었고 Y.F.C 및 V.F.C 모두 같은 형태였으나 각 용해속도에 있어서는 차이가 있었다. 4. Sericin 수용액의 표면장력 측정결과 처리후 방치 시간에 따른 변화 속도는 45분 이내에서 V.F.C가 빠르기 때문에 sericin의 용해성을 저하시킬 것으로 사료된다. 5. Sericin 입자의 비용적에 있어서 Y.F.C가 V.F.C 보다 크기 때문에 Y.F.C의 용해성이 좋은 것으로 추정된다. 6. 제사가공 중 견층 sericin 용해량은 Y.F.C가 V.F.C 보다 초기용해속도가 빠르기 때문에 전공정 sericin 유실량이 많았고 이 때문에 실켜기 공정에서 고치실의 풀림새를 향상시킨 것으로 사료된다.