Effects of Different Purification Methods on Chicken Feather Keratin

Transcription

1 Advanced Materials Research Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland Effects of Different Purification Methods on Chicken Feather Keratin Firoozeh Pourjavaheri 1, a, Farzad Mohaddes 2, b, Robert A. Shanks 1, c, Michael Czajka 1, d and Arun Gupta 3, e 1 School of Applied Sciences, RMIT University, VIC 3000 Australia 2 Centre for Advanced Materials and Performance Textiles, RMIT University, Australia 3 Faculty of Chemical and Natural Resources Engineering, Universiti Malaysia Pahang, Gambang Campus, 25100, Kuantan, Pahang, Malaysia a firoozeh.jad@student.rmit.edu.au, b farzad.mohaddes@rmit.edu.au, c robert.shanks@rmit.edu.au, d MC1@pobox.com, e arun@ump.edu.my Keywords: keratin; purification; protein; poultry; chicken feathers Abstract. Every year billion kilograms of unused feathers result from the poultry industry worldwide, which in effect impose a difficult disposal process to the environment. Chicken feathers are considered as a valuable and renewable keratin protein source, which could be used advantageously in a number of applications as alternatives to feather meal and feather disposal. Although the potential applications of keratin derived from chicken feathers have been investigated, the initial purification phase has not been fully described in the literature. Original chicken feathers contain many biological organisms along with other contaminants after plucking. Unprocessed chicken feathers are considered as potentially hazardous biological materials due to the presence of blood borne pathogens; therefore, the decontamination process is very important. The purpose of this work is to compare the effects of different purification techniques on chicken feathers prior to keratin isolation. These processes include surfactant washing, soxhlet extraction with ethanol, ozone, and sodium chlorite solutions. Thermogravimetric analysis, vibrational spectroscopy, and wide angle X-ray scattering were used to characterise the purified feathers prior to keratin extraction. Introduction Chicken feathers are a good source of natural fiber keratin, which is potentially valuable biopolymer. The amount of this waste is continuously increasing, in conjunction with the increase in fowl meat production. Many publications proposing applications for keratin preparations in the medical industries are described in literature and opportunities to use this interesting protein in other fields have arisen. Utilization of chicken feathers will be beneficial for the poultry industry by reducing health hazards and will benefit the environment by reducing solid wastes being sent to landfills [1]. The current project solves the environmentally sensitive problem of waste disposal. As unprocessed chicken feathers are a potential biological hazard, it is imperative that they are decontaminated before application. Although several investigations have been conducted to explore the possible applications of keratin extracted from chicken feathers, the initial decontamination phase has not been fully described. The aim of this study is to perform a comparative study of different purification approaches that can be used for chicken feathers prior to keratin isolation. The methods include surfactant washing using an ionic and a non-ionic surfactant. Soxhlet extraction with ethanol was performed to efficiently extract fatty and waxy materials. Ozone and sodium chlorite bleaching were used to sterilize and whiten the keratin. Thermogravimetric analysis, Raman, and wide angle X-ray scattering were used to characterise the feathers and residues after purification and prior to keratin extraction. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-11/05/16,05:45:20)

2 Advanced Materials Research Vols Experimental Materials Chicken feathers were supplied by Baiada Poultry Pty Ltd. Sodium lauryl sulphate (SLS) was supplied by BDH Chemicals Ltd. Poly(ethylene glycol) (PEG) was supplied by Sigma-Aldrich. 28 % m/v sodium chlorite (Na + ClO 2 - ) and 20 % m/v citric acid (C 6 H 8 O 7 ) were prepared from Sigma-Aldrich chemicals. Milli-Q pure water was used. All chemicals were of analytical grade and used as received without further purification. Purification processes The following purification methods were applied for decontaminating chicken feathers prior to keratin isolation: (a) purification with an anionic surfactant (SLS) and a non-ionic surfactant (PEG), (b) Soxhlet extraction with ethanol, and (c) bleaching using ozone and sodium chlorite solutions. Thermogravimetric analysis (TGA) In order to assess thermal stability of the samples, thermogravimetric analysis (TGA) was performed using a Perkin-Elmer TGA 7 thermogravimetric analyser, in a temperature range between 30 C and 600 C, at heating rate of 20 C min -1 under nitrogen purge. Sampling mass was chosen to be ~ 2 mg to minimise the effect of thermal lag. Analysis was performed on the untreated and treated chicken feathers. Vibrational spectroscopic analysis A Perkin Elmer Raman Station 400F was used to record spectra of the materials: 785 nm, max output of 250 mw and 100 micron laser spot size. Samples were placed on a glass slide. The sample was centred using the video camera. Focusing was carried out via the Raman option (where the signal was strongest). A scan of 5 s was repeated 4 times (for optimal Raman spectra of feathers). X-ray diffraction A Bruker D8 Discover model diffractometer equipped with a General Area Detector Diffraction System (GADDS) micro X-ray diffractometer with Bragg Brentano parafocusing geometry, a diffracted beam monochromator, and a copper target X-ray tube set to 40 kv and 40 ma used for the X-ray diffraction studies. Diffraction patterns of the chicken feather rachis and barbs were obtained on the Bruker X-ray diffractometer. Samples were mounted on a specially designed sample holder so that the X-ray beam was perpendicular to the sample. The feather calamus/rachis (ß-sheet) and barb/barbules (α-helix) were targeted to obtain X-ray diffraction patterns from the Bruker diffractometer and the diffractograms were analysed to calculate crystallinity percentage. Diffraction patterns were recorded with a 2Q range of 2º - 40º using a copper target X-ray tube set to 40 kv and 40 ma. crystallinity percentage of each sample was calculated by manually subtracting the background and amorphous regions from the crystalline peaks. Results and Discussion Thermogravimetric analysis (TGA) Thermal properties of untreated and treated chicken feathers using the previously mentioned methods were investigated by TGA as shown in Fig. 1. The TGA curves as a function of temperature of the chicken feathers show rapid decomposition in the temperature range between 225 C and 500 C. The resulted curves looked very similar but a close examination of the derivative diagrams showed that the peak temperature of decomposition varies significantly: i.e. SLS, ClO 2, and ozone all resulted in lower decomposition temperature (373 C, 345 C, and 349 C) whereas ethanol and PEG resulted in higher decomposition temperatures (364 C and 365 C); the decomposition temperature was only 363 C for untreated feathers.

3 1186 Materials and Processes Technologies V According to Khosa et al. (2013), the increase in thermal stability (i.e. ethanol and PEG) indicates esterification of the protein [2]. At the completion of the pyrolysis, a total weight loss of ~ 80 % was observed. The absorbed water decomposed below 100 C for chicken feathers with a more dramatic difference in the case of ozone. The ozone and ClO 2 (oxidants) resulted in a decreased thermal stability. Table 1: Peak decomposition temperature of purified and untreated chicken feathers Figure 1: Comparison of the thermogravimetric (TG) curves for untreated and treated chicken feathers along with their derivatives (DTG) curves Vibrational Spectroscopy Chemical fingerprinting of nanostructured carbon-containing materials can be carried out by Raman spectroscopy [3,4]. Raman spectroscopy was carried out on chicken feathers before and after different purification processes (surfactant washing, soxhlet extraction with ethanol, treatment with ozone and sodium chloride solutions). Residues from soxhlet extraction were also characterised similarly. Raman spectra of a single barb and rachis from chicken feathers are shown in Fig. 2. Bands associated with phenylalanine, the S-S band at 400 cm -1 and amide III bands appearing between 1200 cm -1 and 1400 cm -1 are present in the chicken feathers spectra. A sharp Raman peak was identified at 1667 cm -1, which was clearly detectable from the broad background Raman scattering covering the range between 1690 cm -1 and 1640 cm -1. This 1667 cm -1 Raman band is associated with amide I vibration of the antiparallel-chain pleated sheet, in which all the peptide groups vibrate in-phase (v(o,o), in the following section). However the residue from ethanol extraction was characterized as a long hydrocarbon chain ester or typical fat (Fig. 3). Figure 2: Raman spectra of a single a) barb and b) rachis from chicken feathers Wide angle X-ray scattering It should be noted that the weak and diffuse scattering of the X-rays by the barbs makes it difficult to clearly identify all the d-spacings of the crystals in barbs. Reddy and Yang (2007) investigated the diffraction patterns and differences in the d-spacings between rachis and the barbs and concluded that

4 Advanced Materials Research Vols the protein crystals in the barbs have a different arrangement than that in the rachis [5]. Although d-spacings results by Reddy and Yang (2007) determined the physical structure of barbs, they cannot be used to conclusively determine the crystalline structure in the barbs. Further research using stronger radiation sources such as synchrotron sources could possibly lead to a better understanding of the structure of protein crystals in various parts of the feathers. The crystal structures of chicken feather washed with SLS surfactant was analysed by WAXD as shown in Fig. 4. Different position and shape of the major peak in calamus/rachis X-ray spectrum compared to barbs/barbules reconfirmed the difference in crystalline structure of different feather parts. Figure 3: Raman spectra of residue from ethanol extraction of chicken feathers Figure 4: Diffraction intensities of a) calamus/rachis and b) barbs/barbules of chicken feathers Conclusions Each of the mentioned purification techniques affected the feathers in a different way. Thermal behaviour of the purified and untreated chicken feathers was studied by TGA, and mass loss trend as a function of temperature was determined for all samples. TGA results showed rapid decomposition occurring between 225 C and 500 C for all feather samples. A close examination of the derivative shows that the peak temperature of SLS, ClO 2 and ozone resulted in lower temperatures of decomposition whereas ethanol and PEG resulted in higher decomposition temperatures in comparison with the untreated feathers. Raman spectroscopy showed no significant changes in the chemical structure of feathers after applied purification treatments; however, the residue from ethanol extraction was characterised as C=O ester and C-H stretching, which suggests the existence of typical fat in the extraction residue. Further studies are required to determine the complex effect of combined purification techniques in order to prepare keratin of higher purity. Acknowledgements The facilities, scientific and technical assistance, of the Australian Microscopy and Microanalysis Research Facility, RMIT University. References [1] A.A. Onifade, N.A. Al-Sane, A.A. Al-Musallam, S. Al-Zarban. A review: Potentials for biotechnological applications of keratin-degrading microorganisms and their enzymes for nutritional improvement of feathers and other keratins as livestock feed resources. Bioresource Technology (1998) 66. [2] M. A.KHOSA, J. WU, & A. ULLAH. Chemical modification, characterization, and application of chicken feathers as novel biosorbents. RSC Advances, 3, (2013). [3] R. SATO BERRÚ, & J. SANIGER, Application of principal component analysis to discriminate the Raman spectra of functionalized multiwalled carbon nanotubes. Journal of Raman Spectroscopy, 37, no. 11, pp (2006). [4] C. THOMSEN, & S. REICH, Raman scattering in carbon nanotubes. Light Scattering in Solid IX. Springer. Topics in Applied Physics, vol. 108, no. 1, pp (2007). [5] N. Reddy and Y. Yang, Thermoplastic Films from Plant Proteins, Journal of applied polymer scinece (2013).

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