Advanced
Degumming of Antheraea yamamai silkworm cocoon
Degumming of Antheraea yamamai silkworm cocoon
International Journal of Industrial Entomology. 2015. Dec, 31(2): 127-131
Copyright © 2015, Korean Society of Sericultural Science
  • Received : November 11, 2015
  • Accepted : December 12, 2015
  • Published : December 31, 2015
Download
PDF
e-PUB
PubReader
PPT
Export by style
Share
Article
Author
Metrics
Cited by
About the Authors
Bong-Seob Shin
boss@knu.ac.kr
Jong-Young Jeon
Jong-Ho Kim
Abstract
Oak silkworm, Antheraea yamamai ( A. yamamai ), has been used for clothing and surgical suture and considered as biomaterial due to RGD tripeptide. This paper reported the degumming conditions of A. yamamai using sodium oleate, high pressure and temperature, and sodium carbonate. Degumming ratio of A. yamamai cocoon using sodium oleate was less than 10%. High pressure and temperature treatment induced 30% weight loss of A. yamamai cocoon. The concentration, treatment temperature and time using sodium carbonate was examined and revealed the following conditions for degumming; 5% owf, 60 min at 100℃. The degummed solution was confirmed using UV and FT-IR spectrometer. Our results can be used to handle A. yamamai silkworm cocoon for further application including material processing.
Keywords
Introduction
Oak silkworms, Antheraea yamamai ( A. yamamai ) silkworm and Antheraea pernyi silkworm, are distributed on the far-east area including Korea, Japan, and northeastern China. Among them, A. yamamai silkworm spins green colored cocoon. The cocoon has been used for clothing, bullet-proof vests for warriors, bowstrings, fishing cords, musical strings, etc. Nowadays, A. yamamai silk has been considered as a possible novel biomaterial because it contains a tripeptide motif called RGD (Arg-Gly-Asp) (Datta ., 2001 ; Minoura ., 1995 ; Ruoslahti & Pierschbacher, 1986) . Biocomaptibiltiy (Wang ., 2011) , gelation (Liu & Zhang, 2014) , degradation (You ., 2014) , and PEG modified film (Wei ., 2014) using A. yamamai silk protein have been investigated. As a possible food resources, the hydrolyzed A. yamamai silk fibroin powder was also examined due to rich glycine, alanine, and serine contents and various bioactivity (Kweon ., 2006) .
Cocoon material is composed of two kinds of proteins, a core protein (fibroin) and a gum-like protein (sericin). The content of sericin in the cocoon is different among the silkworm cocoons spun by silkworm kinds. To use A. yamamai silk fibroin for various application including clothing and biomaterial, degumming, a process to remove sericin, is an essential process. Reported degumming method for A. yamamai raw silk was sodium carbonate method and enzymatic method (Lee ., 2013 ; Shin ., 2012 ; Kawahara and Nakajima, 1992) .
In this study, we examined the condition of A. yamamai cocoon degumming according to the temperature and concentration of sodium carbonate and measured the UV absorption characteristics of degummed solution and IR absorption characteristics of degummed A. yamamai cocoon.
Materials and Methods
- Materials
A. yamamai silkworm cocoon was harvested at the farm of National Academy of Agricultural Science. Sodium carbonate, sodium oleate were purchased and used without further purification.
- Degumming
The cocoon was degummed with physical method using autoclave and chemical methoud using various concentration of sodium salt and then washed with distilled water. Degumming loss percentage was calculated according to the following equation.
Degumming loss percentage (%) = (Wi – Wf) / Wi × 100
Where, Wi is initial weight of dry cocoon; Wf final weight of dry cocoon.
- Structural characterization
Ultra violet spectrometer (Lambda 10, Perkin Elmer, USA) was used to measure the UV absorbance patterns of degummed Antheraea yamamai silkworm cocoon solution.
Fourier transform infrared (FT-IR) absorbance spectra were obtained using FT-IR spectrometer (Spectrum 100, Perkin Elmer, USA) in the spectral region of 1800 ~ 1000 cm -1 at a resolution of 2 cm -1 and 32 repeated scans were averaged for each spectrum.
Results and Discussion
- Degumming condition ofA. yamamaisilkworm cocoon
To impose unique silk fabrics characteristics, raw silk has been degummed during the textile processing. Soap degumming is one of a common method for domestic silk degumming. The main component of soap is sodium oleate. Fig. 1 showed degumming ratio of A. yamamai and B. mori silkworm cocoon at 100℃. After 30 min treatment, domestic silkworm cocoon showed around 25%. On the other hand, even though 120 min treated, wild silkworm cocoon showed less than 10%.
PPT Slide
Lager Image
Degumming ratio of Antheraea yamamai silkworm cocoon and Bombyx mori silkworm cocoon with sodium oleate 12% owf aqueous solution at 100℃.
Wild silkworm A. yamamai cocoon has calcium oxalate crystal on its surface (Lee ., 2015 ; Freddi ., 1994) . Calcium oxalate might prevent the action of sodium oleate to remove silk sericin from the filament. This data showed that soap degumming method is not good for A. yamamai silkworm cocoon.
Fig. 2 showed degumming ratio of A. yamamai and B. mori silkworm cocoon using autoclave. Sericin can be extracted by boiling the silkworm cocoon in water because sericin is water soluble protein (Kwak ., 2013 ; Oh ., 2011) . B. mori silkworm cocoon was degummed about 20% with high pressure and temperature water. On the other hand, degummed ratio of wild silkworm cocoon showed about 30%.
PPT Slide
Lager Image
Degumming ratio of Antheraea yamamai silkworm cocoon and Bombyx mori silkworm cocoon with high pressure and high temperature at 120℃.
Fig. 3 showed degumming ratio of A. yamamai silkworm cocoon using sodium carbonate. Degumming ratio of A. yamamai cocoon was increased with degumming time and temperature. When A. yamamai cocoon were treated for 60 min at 100℃, the degumming ratio of the wild cocoon treated with 1% owf, 5% owf, 10% owf was 22.5%, 30%, and 28.2%, respectively. So, the best condition of alkali degumming for A. yamamai cocoon is 5% owf sodium carboante with 60 min at 100℃.
PPT Slide
Lager Image
Degumming ratio of Antheraea yamamai silkworm cocoon with sodium carbonate; sodium carabonate 1% owf aqueous solution (a), sodium carbonate 5% owf solution (b), sodium carbonate 10% owf solution (c).
Degumming ratio was reported various researchers using different degumming process. Shin . (2012) reported alkaline degumming ratio of A. pernyi and B. mori silkworm cocoon were 17.1% and 25.0%, respectively. Alkali degumming ratio of A. pernyi raw silk was 16.8% (Lee ., 2013) . Enzymatic degumming loss of raw silk spun by A. pernyi , A. yamamai , and A. assama silkworm were 11.6%, 16.0%, and 7.4% (Kawahara and Nakajima, 1992) . Common Korean B. mori silkworm variety, Baegokjam, was reported 25.4% (Kweon ., 2012) .
- UV spectra ofA. yamamaisericin
A. yamamai degummed solution is expected to contain A. yamamai sericin extracted by degumming process. Sericin is a protein produced by silkworm. Generally, protein absorbs at 280 nm near-ultraviolet region due to the electron transfer of aromatic amino acid, tryptophan, tyrosine, and phenylalanine. As expected ( Fig. 4 ), A. yamamai degummed solution showed strong absorption band at 280 nm. This phenomena is similar to the UV spectra of sericinjam sericin (Kim ., 2009) . The UV absorption intensity of degummed solution is coincidence with the degumming ratio of the wild silkworm ( Fig. 3 ).
PPT Slide
Lager Image
UV spectra of Antheraea yamamai degummed solution
PPT Slide
Lager Image
FT IR spectra of degummed Antheraea yamamai cocoon.
- FTIR spectra of degummedA. yamamaicocoon
FT-IR is a powerful technique to examine the conformation of protein. In particular, the position and intensity of amide bands are sensitive to molecular conformation of silk protein. The spectrum of wild silkworm cocoon showed strong absorption band at 1650 cm -1 (amide I), 1530 cm -1 (amide II), attributed to the α-helix conformation (Kweon ., 2001) . Amide I and amide II absorption bands were shifted to lower wavenumber due to the degumming process.
The degumming condition for A. yamamai silkworm cocoon was examined. The highest degumming condition is 5% owf sodium carbonate with 60 min at 100℃. The degummed solution showed strong UV absorption band at 280 nm and degummed cocoon showed amide band shift to lower wavenumber.
Acknowledgements
This study was supported by the Kyungpook National University Research Fund, 2012.
References
Datta A , Ghosh AK , Kundu SC (2001) Purification and characterization of fibroin from the tropical saturniid silkworm, Antheraea mylitta. Insect Biochem Mol Biol 31 1013 - 1018
Freddi G , Gotoh Y , Mor T , Tsubsui I , Tsukada M (1994) Chemical structure and physical properties ofAntheraea assamasilk. J Appl Polym Sci 52 775 - 781
Kawahara Y , Nakajima S (1992) Surface and mechanical properties of wild silk fibers degummed with enzyme. J Seric Sci Jpn 61 460 - 462
Kim JH , Shin BS , Lee KG , Yeo JH , Kweon HY (2009) Sericinjam sericin: structure and thermal properties. Int J Indust Entomol 19 255 - 258
Kwak HW , Yang YS , Kim MK , Lee JY , Yun H , Kim MH , Lee KH (2013) Chromium(VI) adsorption behavior of silk sericin beads. Int J Indust Entomol 26 47 - 53
Kweon HY , Lee K , Park K , Kang S , Seok Y (2012) Degumming characteristics and color stability of GoldenSilk cocoon. Int J Ind Entomol 24 1 - 5
Kweon HY , Lee KG , Yeo JH , Woo SO , Han SM , Sohn BH , Lee HS , Shin BS (2006) Characterization of hydrolyzedAntheraea yamamaisilk fibroin powder. Korean J Seric Sci 48 11 - 15
Kweon HY , Um IC , Park YH (2001) Structure and thermal characteristics ofAntheraea pernyisilk fibroin/chitosan blend film. Polym 42 6651 - 6656
Lee KG , Jo YY , Yeo JH , Lee HS , Kim KY , Park KY , Kweon HY (2013) Dissolution ofAntheraea pernyiraw silk with calcium nitrate ethanol solution. J Seric Entomol Sci 51 15 - 19
Lee KG , Chung DE , Kim KY , Jo YY , Kim H , Kim S , Kweon HY (2015) General characteristics ofAntheraea yamamaisilkworm cocoon cultured in Korea. J Seric Entomol Sci 53 6 - 11
Minoura N , Aiba SI , Higuchi M , Gotoh Y , Tsukada M , Imai Y (1995) Attachment and growth of fibroblast cells on silk fibroin. Biochem Biophys Res Commun 208 (2) 511 - 516
Liu Y , Zhang Y (2014) Control of the gelation process of silk fibroin solution. Thermal Science 18 1587 - 1590
Moy RL , Lee A , Zalka A (1991) Commonly used suture materials in skin surgery. Am Fam Physician 44 2123 - 2128
Oh HJ , Lee JY , Kim MK , Um IC , Lee KH (2011) Refining hot-water extracted silk sericin by ethanol-induced precipitation. Int J Biol Macromol 48 32 - 37
Ruoslahti E , Pierschbacher MD (1986) Arg-Gly-Asp: a versatile cell recognition signal. Cell 44 517 - 518
Shin BS , Jeon JY , Kim JH (2012) Cocoon characteristics ofAntheraea pernyisilkworm rearing in Korean oak field. Int J Indust Entomol 25 205 - 208
Wang J , Yi H , Wei Y (2011) Preliminary biocompatibility evaluation of regeneratedAntheraea yamamaisilk fibroin in vitro. J Wuhan Univ Tech Mater Sci Ed 26 1044 - 1048
Wei Y , Sun D , Yi H , Wang J (2014) Characterization of a PEG-DE crosslinked tubular silk scaffold. Text Res J 84 959 - 967
You R , Xu Y , Liu Y , Li X , Li M (2014) Comparison of the in vitro and in vivo degradations of silk fibroin scaffolds from mulberry and nonmulberry silkworms. Biomed Mater 10 015003 -