Graft polymerization of native chicken feathers for thermoplastic applications

Analysis of thermal decomposition kinetics of chicken feather fiber reinforced Poly-lactic acid composites filament

Derivative Thermogravimetric analysis under air was used to observe the thermal decomposition process of Chicken feather fiber (CFF) reinforced Poly-lactic acid (PLA) composite filament of 2.2 mm diameter. The thermal degradation of the sample was initiated at 140 ֯C. Approximately 75 % of the thermal degradation occurred between the temperature of 357 ֯C and 399 ֯C. The composite's activation energy was established using the Coats-Redfern method. The results showed that the activation energy of 112.06 kJ/mol is utilized for the sample throughout the temperature range of 23 ֯C to 398 ֯C. A low activation energy is indicative of rapid chemical reactions between the CFF and PLA molecules. The results from TGA and DTGA indicate that the addition of CFF in the PLA matrix enhanced the thermal stability.

Preparation Methods and Functional Characteristics of Regenerated Keratin-Based Biofilms

The recycling, development, and application of keratin-containing waste (e.g., hair, wool, feather, and so on) provide an important means to address related environmental pollution and energy shortage issues. The extraction of keratin and the development of keratin-based functional materials are key to solving keratin-containing waste pollution. Keratin-based biofilms are gaining substantial interest due to their excellent characteristics, such as good biocompatibility, high biodegradability, appropriate adsorption, and rich renewable sources, among others. At present, keratin-based biofilms are a good option for various applications, and the development of keratin-based biofilms from keratin-containing waste is considered crucial for sustainable development. In this paper, in order to achieve clean production while maintaining the functional characteristics of natural keratin as much as possible, four important keratin extraction methods—thermal hydrolysis, ultrasonic technology, eco-friendly solvent system, and microbial decomposition—are described, and the characteristics of these four extraction methods are analysed. Next, methods for the preparation of keratin-based biofilms are introduced, including solvent casting, electrospinning, template self-assembly, freeze-drying, and soft lithography methods. Then, the functional properties and application prospects of keratin-based biofilms are discussed. Finally, future research directions related to keratin-based biofilms are proposed. Overall, it can be concluded that the high-value conversion of keratin-containing waste into regenerated keratin-based biofilms has great importance for sustainable development and is highly suggested due to their great potential for use in biomedical materials, optoelectronic devices, and metal ion detection applications. It is hoped that this paper can provide some basic information for the development and application of keratin-based biofilms.

Chicken Feather Waste Valorization Into Nutritive Protein Hydrolysate: Role of Novel Thermostable Keratinase From Bacillus pacificus RSA27

Microbial keratinases exhibit a momentous role in converting keratin biowastes into exceedingly valuable protein supplements. This study reports a novel, highly stable keratinase from Bacillus pacificus RSA27 for the production of pure peptides rich in essential amino acids from chicken feathers. Purified keratinase showed a specific activity of 38.73 U/mg, 2.58-fold purification, and molecular weight of 36 kDa. Kinetic studies using a chicken feather as substrate report K_m and V_max values of 5.69 mg/ml and 142.40 μg/ml/min, respectively, suggesting significant enzyme-substrate affinity/biocatalysis. Identification and in silico structural-functional analysis of keratinase discovered the presence of distinct amino acid residues and their positions. Besides, keratinase possesses a high-affinity calcium-binding site (Asp¹²⁸, Leu¹⁶², Asn¹⁶⁴, Ile¹⁶⁶, and Val¹⁶⁸) and a catalytic triad of Asp¹¹⁹, His¹⁵¹, and Ser³⁰⁸, known attributes of serine protease (subtilisin family). Furthermore, a scale-up to 5 L fermenter revealed complete feather hydrolysis (94.5%) within 24 h with high activity (789 U/ml) and total amino acid of 153.97 μmol/ml. Finally, cytotoxicity evaluation of protein hydrolysate resulted in negligible cytotoxic effects (1.02%) on the mammalian hepatoblastoma cell line, signifying its potential biotechnological applications.

Bio-plastic Films Production from Feather Waste Degradation by Keratinolytic Bacteria Bacillus cereus

Plastic materials have become a necessity of human life especially in the packaging of food commodities and biomedical procedures. Bioplastic is emerging as an effective alternative to fossil oil-based materials to avoid the environmental hazards of the plastic industry. During this study, chicken feathers were used as a substrate to isolate keratin degrading bacteria. Among 14 identified isolates, Bacillus sp BAM3 was found to be the most promising isolate. Partial 16S rDNA analysis-based molecular characterization revealed it is a strain of Bacillus cereus. Bacillus sp BAM3 can grow and produce keratinase in feathers containing basal medium as the sole carbon and energy source. The maximum keratinase production (730U/ml) was achieved within 24 h under optimum reaction conditions. The optimized reaction pH and temperature were noted as 9.0 and 50 °C for crude keratinase activity, respectively. The chicken feathers were used as a substrate in 2, 5, and 10 wt% glycerol to synthesize keratin-based bioplastic with keratinolytic bacterium Bacillus cereus BAM3. Bioplastic prepared from keratin with 2% of glycerol was found to possess good mechanical properties. Therefore, the results present a novel keratinolytic isolate of Bacillus cereus BAM3, which may have potential biotechnological applications in keratin hydrolysis processes. The development of keratin-based bioplastics possessing superior crystalline morphology requires further investigations to substitute fossil oil-based materials.

Keratin - Based materials for biomedical applications

Keratin constitutes the major component of the feather, hair, hooves, horns, and wool represents a group of biological material having high cysteine content (7-13%) as compared to other structural proteins. Keratin -based biomaterials have been investigated extensively over the past few decades due to their intrinsic biological properties and excellent biocompatibility. Unlike other natural polymers such as starch, collagen, chitosan, the complex three-dimensional structure of keratin requires the use of harsh chemical conditions for their dissolution and extraction. The most commonly used methods for keratin extraction are oxidation, reduction, steam explosion, microbial method, microwave irradiation and use of ionic liquids. Keratin -based materials have been used extensively for various biomedical applications such as drug delivery, wound healing, tissue engineering. This review covers the structure, properties, history of keratin research, methods of extraction and some recent advancements related to the use of keratin derived biomaterials in the form of a 3-D scaffold, films, fibers, and hydrogels.

Thermal responsive poly(N-isopropylacrylamide) grafted chicken feather keratin prepared via surface initiated aqueous Cu(0)-mediated RDRP: Synthesis and properties

Poultry chicken feather keratin was extracted and then modified for the fabrication of keratin-graft-PNIPAM copolymers. The keratin was well extracted from feather fiber and powdered. Subsequently, it underwent the surficial functionalization process with initiator groups. After the study conducted full disproportionation of Cu(I)Br/Me₆Tren into Cu(0) and Cu(II)Br₂ in the solvent, surface initiated aqueous Cu(0)-mediated reversible-deactivation radical polymerization (RDRP) of N-isopropylacrylamide (NIPAM) was performed in a methanol/water mixture solvent. The reaction was performed rapidly and efficiently, during which over 100% graft rate was achieved at 60 min. After 6 h reaction, 200% graft rate could be achieved. High graft rate (up to 287%) was achieved, and graft rate could be regulated by controlling the reaction time and the addition of monomer. The fabricated keratin-g-PNIPAM exhibited a rough surface. As revealed from the results of thermal analysis, the thermal stability of keratin-g-PNIPAM was enhanced noticeably compared with the original keratin. Besides, grafted PNIPAM chains exhibited a higher glass transition temperature. The grafted keratin particles displayed enhanced hydrophilicity. Keratin-g-PNIPAMs exhibit a lower LCST comparing to homopolymer and the flocculation in hot water behavior could be controlled by regulating graft rate.

Salt-Free Dyeing of Modified Cotton through Graft Polymerization with Highly Enhanced Dye Fixation and Good Strength Properties

Modification of cotton fabric with 2-methacryloyloxyethyltrimethyl ammonium chloride (DMC) was achieved through free-radical initiated graft polymerization with K₂S₂O₈/NaHSO₃ as the initiator. Grafting of DMC was confirmed by ATR-IR of the modified cotton. The optimal grafting reaction conditions, including DMC dosage, mole ratio of initiator to DMC, temperature, and time, were determined by cation content and dye fixation results of the modified cotton. The modified fibers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and whiteness measurement. Salt-free dyeing of the modified cotton with commonly used C. I. Reactive Blue 19, C. I. Reactive Yellow 145, and C. I. Reactive Red 195 presented high fixation of 96.8%, 98.7%, and 97.3%, respectively. These results indicated that the modification is effective for changing the surface charge of the fiber and increasing the dye-fiber reactivity. The color fastness and strength property were still very satisfactory. With excellent properties, this dyeing method shows promise in real application for eliminating the usage of salt and reducing environmental pollution.

Electrospun Silver Nanoparticles-Embedded Feather Keratin/Poly(vinyl alcohol)/Poly(ethylene oxide) Antibacterial Composite Nanofibers

Feathers, which contain >90% keratin, are valuable natural protein resources. The aim of this study is to prepare antimicrobial feather keratin (FK)-based nanofibers by incorporating silver nanoparticles (AgNPs). A series of AgNPs-embedded feather keratin/poly(vinyl alcohol)/poly(ethylene oxide) (FK/PVA/PEO) composite nanofibers with varying amounts of AgNPs content were fabricated by electrospinning. Their morphology, crystallinity, thermal stability, tensile property, and antibacterial activity were systematically investigated. The average diameters of composite nanofibers gradually decreased with increases in the amount of AgNPs. The crystallinity, thermal stability, and antibacterial activity of FK/PVA/PEO nanofibers were enhanced by embedding AgNPs. When embedded with 1.2% AgNPs, both the tensile strength and elongation-at-break reached the highest level. This work has the potential to expand the application of FK-based nanofibers in the biomaterial field.

Improving Thermal, Mechanical, and Barrier Properties of Feather Keratin/Polyvinyl Alcohol/Tris(hydroxymethyl)aminomethane Nanocomposite Films by Incorporating Sodium Montmorillonite and TiO₂

In this study, feather keratin/polyvinyl alcohol/tris(hydroxymethyl)aminomethane (FK/PVA/Tris) bionanocomposite films containing two types of nanoparticles, namely one-dimensional sodium montmorillonite (MMT) clay platelets (0.5, 1, 3, and 5 wt%) and three-dimensional TiO₂ nanospheres (0.5, 1, 3, and 5 wt%), are prepared using solvent casting method. X-ray diffraction studies confirm the completely exfoliated structure of FK/PVA/Tris/MMT nanocomposites. The successful formation of new hydrogen bonds between the hydroxyl groups of the film matrix and the nanofillers is confirmed by Fourier transform infrared spectroscopy. The tensile strength, elongation at break, and initial degradation temperature of the films are enhanced after MMT and TiO₂ incorporation. The water vapor permeability, oxygen permeability, and light transmittance decrease with increase in TiO₂ and MMT contents. In summary, nanoblending is an effective method to promote the application of FK/PVA/Tris blend films in the packaging field.

Physiochemical characteristics and bone/cartilage tissue engineering potentialities of protein-based macromolecules - A review

Protein-based macromolecules such as keratin, silk fibroin, collagen, gelatin, and fibrin have emerged as potential candidate materials with unique structural and functional characteristics. Despite many advantages, the development of tissue-engineered constructs that can match the biological context of real tissue matrix remains a challenge in tissue engineering (TE). The tissue-engineered constructs should also support vascularization. Protein-based macromolecules, in pristine or combine form, provide a promising platform to engineer constructs with unique design and functionalities which are highly essential for an appropriate stimulation and differentiation of cells in a specific TE approach. However, much work remains to be undertaken with particular reference to in-depth interactions between constructed cues and target host tissues. Thus, modern advancements are emphasizing to understand critiques and functionalization of protein-based macromolecule that organize not only cellular activities but also tissue regenerations. In this review, numerous physicochemical, functional, and structural characteristics of protein-based macromolecules such as keratin, silk fibroin, collagen, gelatin, and fibrin are discussed. This review also presents the hope vs. hype phenomenon for tissue engineering. Later part of the review focuses on different requisite characteristics and their role in TE. The discussion presented here could prove highly useful for the construction of scaffolds with requisite features.

Improving the Water Resistance and Mechanical Properties of Feather Keratin/Polyvinyl Alcohol/Tris(Hydroxymethyl)Aminomethane Blend Films by Cross-Linking with Transglutaminase, CaCl₂, and Genipin

The high moisture sensitivity of feather keratin/polyvinyl alcohol/tris(hydroxymethyl)aminomethane (FK/PVA/Tris) blend films hinders their application in the packaging field. Thus, in order to improve the water resistance and mechanical properties of such blend films, we attempted cross-linking the blend film with cross-linking agents such as transglutaminase (TG), CaCl₂, and genipin. Obvious differences in the morphology of the blended films were observed by scanning electron microscopy before and after cross-linking, indicating that cross-linking can inhibit the phase separation of the blend film. Conformational changes in the blend films after cross-linking were detected by Fourier transform infrared spectroscopy. Importantly, from examination of the total soluble mass, contact angle measurements, and water vapor permeability tests, it was apparent that cross-linking greatly improved the water resistance of the blend films, in addition to enhancing the mechanical properties (i.e., tensile strength and elongation at break). However, cross-linking was also found to reduce the oxygen barrier properties of the blend films. Therefore, cross-linking appears to be an effective method for promoting the application of FK/PVA/Tris blend films in the packaging field.

The past, present and future of protein-based materials

Protein-based materials are finding new uses and applications after millennia of impacting the daily life of humans. Some of the earliest uses of protein-based materials are still evident in silk and wool textiles and leather goods. Today, even as silks, wools and leathers are still be used in traditional ways, these proteins are now seen as promising materials for biomaterials, vehicles of drug delivery and components of high-tech fabrics. With the advent of biosynthetic methods and streamlined means of protein purification, protein-based materials-recombinant and otherwise-are being used in a host of applications at the cutting edge of medicine, electronics, materials science and even fashion. This commentary aims to discuss a handful of these applications while taking a critical look at where protein-based materials may be used in the future.

Preparation and Physicochemical Properties of Blend Films of Feather Keratin and Poly(vinyl alcohol) Compatibilized by Tris(hydroxymethyl)aminomethane

Blend films of feather keratin (FK) and synthetic poly(vinyl alcohol) (PVA) that were compatibilized by tris(hydroxymethyl)aminomethane (Tris) were successfully prepared by a solution-casting method. The scanning electron microscopy (SEM) results showed that a phase separation occurred in the FK/PVA/Tris blended system. Analysis by Fourier transform infrared spectroscopy indicated that the main interactions between the three components were hydrogen bonds. In addition, X-ray diffraction analysis showed that the FK/PVA/Tris blend films were partially crystalline. The barrier properties, mechanical properties, and contact angles of the FK/PVA/Tris films were investigated to determine the effects of the PVA and Tris concentrations. More specifically, upon increasing the PVA content, the elongation at break, the hydrophilicity, and the oxygen barrier properties were enhanced. However, at a constant PVA content, an increase in the Tris content caused the oxygen permeability and the contact angle to decrease, while the tensile strength, elongation at break, and oxygen barrier properties were enhanced. These results indicated that the mechanical properties and gas resistance of the FK/PVA/Tris blend films could be successfully improved using the method described herein, confirming that this route provided a convenient and promising means to prepare FK plastics for practical applications.

Keratin: dissolution, extraction and biomedical application

Keratinous materials such as wool, feathers and hooves are tough unique biological co-products that usually have high sulfur and protein contents. A high cystine content (7-13%) differentiates keratins from other structural proteins, such as collagen and elastin. Dissolution and extraction of keratin is a difficult process compared to other natural polymers, such as chitosan, starch, collagen, and a large-scale use of keratin depends on employing a relatively fast, cost-effective and time efficient extraction method. Keratin has some inherent ability to facilitate cell adhesion, proliferation, and regeneration of the tissue, therefore keratin biomaterials can provide a biocompatible matrix for regrowth and regeneration of the defective tissue. Additionally, due to its amino acid constituents, keratin can be tailored and finely tuned to meet the exact requirement of degradation, drug release or incorporation of different hydrophobic or hydrophilic tails. This review discusses the various methods available for the dissolution and extraction of keratin with emphasis on their advantages and limitations. The impacts of various methods and chemicals used on the structure and the properties of keratin are discussed with the aim of highlighting options available toward commercial keratin production. This review also reports the properties of various keratin-based biomaterials and critically examines how these materials are influenced by the keratin extraction procedure, discussing the features that make them effective as biomedical applications, as well as some of the mechanisms of action and physiological roles of keratin. Particular attention is given to the practical application of keratin biomaterials, namely addressing the advantages and limitations on the use of keratin films, 3D composite scaffolds and keratin hydrogels for tissue engineering, wound healing, hemostatic and controlled drug release.

Keratin based bioplastic film from chicken feathers and its characterization

Plastics have been one of the highly valued materials and it plays an significant role in human's life such as in food packaging and biomedical applications. Bioplastic materials can gradually work as a substitute for various materials based on fossil oil. The issue like sustainability and environmental challenges which occur due to manufacturing and disposal of synthetic plastics can be conquering by bio-based plastics. Feathers are among the most inexpensive abundant, and renewable protein sources. Feathers disposal to the landfills leads to environmental pollutions and it results into wastage of 90% of protein raw material. Keratin is non-burning hydrophilic, and biodegradable due to which it can be applicable in various ways via chemical processing. Main objective of this research is to synthesis bioplastic using keratin from chicken feathers. Extracted keratin solution mixed with different concentration of glycerol (2 to 10%) to produce plastic films. The mixture was stirred under constant magnetic stirring at 60 °C for 5 h. The mixtures are then poured into aluminum weighing boat and dried in an oven at 60 °C for 24 h. The mechanical properties of the samples were tested and the physic-chemical properties of the bioplastic were studied. According to the results, Scanning Electron Microscopy test showed good compatible morphologies without holes, cavity and edge. The difference in chemical composition was analyzed using Fourier transform infrared spectroscopy (FTIR). The samples were also characterized by thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-Ray diffraction (XRD) to check the thermal and crystallinity properties. Other than that, bioplastic made up from keratin with 2% of glycerol has the best mechanical and thermal properties. According to biodegradability test, all bioplastic produced are proven biodegradable. Therefore, the results showed possible application of the film as an alternative to fossil oil based materials which are harmful to the environment.

Development of a keratinase activity assay using recombinant chicken feather keratin substrates

Poultry feathers consist mainly of the protein keratin, which is rich in β-pleated sheets and consequently resistant to proteolysis. Although many keratinases have been identified, the reasons for their substrate specificity towards β-keratin remain unclear due to difficulties in preparing a soluble feather keratin substrate for use in activity assays. In the present study, we overexpressed Gallus gallus chromosomes 2 and 27 β-keratin-encoding genes in Escherichia coli, purified denatured recombinant proteins by Ni²⁺ affinity chromatography, and refolded by stepwise dialysis to yield soluble keratins. To assess the keratinolytic activity, we compared the proteolytic activity of crude extracts from the feather- degrading bacterium Fervidobacterium islandicum AW-1 with proteinase K, trypsin, and papain using purified recombinant keratin and casein as substrates. All tested proteases showed strong proteolytic activities for casein, whereas only F. islandicum AW-1 crude extracts and proteinase K exhibited pronounced keratinolytic activity for the recombinant keratin. Moreover, LC-MS/MS analysis of keratin hydrolysates allowed us to predict the P1 sites of keratinolytic enzymes in the F. islandicum AW-1 extracts, thereby qualifying and quantifying the extent of keratinolysis. The soluble keratin-based assay has clear therapeutic and industrial potential for the development of a high-throughput screening system for proteases hydrolyzing disease-related protein aggregates, as well as mechanically resilient keratin-based polymers.

Fabrication and characterization of electrospun feather keratin/poly(vinyl alcohol) composite nanofibers

We have fabricated random and aligned feather keratin (FK)/PVA composite nanofibers through an electrospinning process. The morphology, molecular interactions, crystallization behavior, and tensile properties of the nanofibers were investigated.

A two in one approach: renewable support and enhanced catalysis for sweetening using chicken feather bound cobalt(ii) phthalocyanine under alkali free environment

Poultry waste chicken feathers, an inexpensive and abundantly available material has been used as a renewable support for immobilizing a cobalt phthalocyanine catalyst.

Magnetically separable chicken feathers: a biopolymer based heterogeneous catalyst for the oxidation of organic substrates

Magnetically separable chicken feather nanoparticles were found to be efficient, green and heterogeneous catalyst for selective oxidation of alcohols to carbonyls and sulfides to sulfoxides using t-butyl hydroperoxide (TBHP) as oxidant.

Grafting poly(2-acryloyloxyethyl trimethyl ammonium chloride) branches onto the backbones of corn starch for toughening starch film

This work was undertaken to examine the effect of poly(2-acryloyloxyethyl trimethyl ammonium chloride) (PATAC) branches grafted onto the backbones of starch on the toughening of starch film. A series of starch-g-PATAC samples having different levels of grafting ratio were prepared by the graft copolymerization of granular corn starch with ATAC in an aqueous system, using Fenton’s initiator through changing the weight ratio of the monomer to starch. The influences of grafted branches on the properties such as tensile strength, breaking elongation, work-to-break, bending endurance, moisture regain, swelling power, and solubility of starch film were evaluated by comparison with those of acid-treated starch (ATS). It was found that the branches were able to toughen starch film due to the significant increases in breaking elongation, work-to-break and bending endurance of the film. The branches were also able to increase its moisture regain, water swelling power, and solubility. In addition, the properties were dependent on the amount of the branches. Furthermore, the grafted starch was biodegradable when its grafting ratio did not exceed 7.5 wt%.

Non-food industrial applications of poultry feathers

Poultry feathers are one of the unique coproducts that have versatile applications ranging from composites, fibers, tissue engineering scaffolds, nano and micro particles, electronic devices and many others. Despite their low cost, abundant availability, wide applicability and unique properties, non-food industrial applications of feather keratin are very limited. Poor-thermoplasticity, difficulty in dissolving keratin and limited knowledge on the processability and properties of products developed are some of the limitations for the large scale use of feather/keratin. Nevertheless, increasing interests in using renewable and sustainable raw materials and need to decrease dependence on non-renewable petroleum resources make feathers an attractive raw material for bioproducts. This review provides an overview of the products developed from poultry feathers and their limitations and advantages.

Preparation and characterization of a dialdehyde starch crosslinked feather keratin film for food packaging application

Crosslink effects of dialdehyde starch on the mechanical properties, water-resistance, compatability, micromorphology, and water vapor barrier property of feather keratin films.

Conversion of chicken feather waste to N-doped carbon nanotubes for the catalytic reduction of 4-nitrophenol

Poultry feather is renewable, inexpensive and abundantly available. It holds great business potentials if poultry feather can be converted into valuable functional materials. Herein, we describe a strategy for the catalytic conversion of chicken feather waste to Ni3S2-carbon coaxial nanofibers (Ni3S2@C) which can be further converted to nitrogen doped carbon nanotubes (N-CNTs). Both Ni3S2@C and N-CNTs exhibit high catalytic activity and good reusability in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 with a first-order rate constant (k) of 0.9 × 10(-3) s(-1) and 2.1 × 10(-3) s(-1), respectively. The catalytic activity of N-CNTs is better than that of N-doped graphene and comparable to commonly used noble metal catalysts. The N content in N-CNTs reaches as high as 6.43%, which is responsible for the excellent catalytic performance. This strategy provides an efficient and low-cost method for the comprehensive utilization of chicken feathers. Moreover, this study provides a new direction for the application of N-CNTs.

One for two: conversion of waste chicken feathers to carbon microspheres and (NH4)HCO3

Pyrolysis of 1 g of waste chicken feathers (quills and barbs) in supercritical carbon dioxide (sc-CO2) system at 600 °C for 3 h leads to the formation of 0.25 g well-shaped carbon microspheres with diameters of 1-5 μm and 0.26 g ammonium bicarbonate ((NH4)HCO3). The products were characterized by powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectroscopic, FT-IR spectrum, X-ray electron spectroscopy (XPS), and N2 adsorption/desorption measurements. The obtained carbon microspheres displayed great superhydrophobicity as fabric coatings materials, with the water contact angle of up to 165.2±2.5°. The strategy is simple, efficient, does not require any toxic chemicals or catalysts, and generates two valuable materials at the same time. Moreover, other nitrogen-containing materials (such as nylon and amino acids) can also be converted to carbon microspheres and (NH4)HCO3 in the sc-CO2 system. This provides a simple strategy to extract the nitrogen content from natural and man-made waste materials and generate (NH4)HCO3 as fertilizer.

Effects of monomers and homopolymer contents on the dry and wet tensile properties of starch films grafted with various methacrylates

Starch grafted with four different methacrylates was compression molded to form thermoplastic films with good strength and water stability. Starch is an inexpensive and biodegradable polymer but is nonthermoplastic and needs to be chemically modified to make starch suitable for various applications. In this research, starch was grafted with four methacrylates (methyl, ethyl, butyl, and hexyl), and the effect of the length of the alkyl ester group on grafting parameters, thermoplasticity, and properties of thermoplastic films developed have been studied. Influence of grafting conditions on % grafting efficiency, % homopolymers, and % monomer conversion were studied, and the grafted starch was characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and nuclear magnetic resonance ((1)H NMR). At similar grafting ratios, butyl methacrylate (BMA) provided better strength and elongation to the starch films than the other three methacrylates. Grafting of methacrylates appears to be an economical approach to develop thermoplastic products from starch.

Improving digestibility of feather meal by steam flash explosion

Poultry feathers are available in large quantities. However, natural feathers have poor digestibility and are often considered as solid wastes. To improve the digestibility of poultry feathers, steam flash explosion (SFE) was applied to duck feathers at different pressures ranging from 0.5 to 2.5 MPa for 1 min. The pepsin digestibility, disulfide bond content, and major secondary structure component (β-sheets) of duck feathers before and after the process were examined. The results showed that SFE could effectively increase pepsin digestibility of feather meal. Under the optimal conditions (1.8 MPa for 1 min), the pepsin digestibility of exploded feather meal achieved approximately 91%, which was about 9 times higher than that of the original feathers. The pepsin digestibility was highly correlated with the degree of reduction of disulfide bonds (R(2) = 0.98) and slightly negatively correlated with β-sheet structure. SFE is an effective method to improve the bio-utilization of feather meal.

Development and characterization of thermoplastic films from sorghum distillers dried grains grafted with various methacrylates

Distillers Dried Grains (DDG) obtained during production of ethanol from grain sorghum were grafted with methacrylates and compression molded into films with good dry and wet tensile properties. Since sorghum DDG contains up to 45% proteins that are indigestible by animals, it is necessary to find alternative applications to make sorghum ethanol economically competitive. In this research, sorghum DDG was grafted with methyl, ethyl, and butyl methacrylates, the grafted DDG was compression molded into films, and the properties of the grafted DDG and films were studied. At a grafting ratio of 40%, butyl methacrylate (BMA) grafted films had a strength of 4.8 MPa and elongation of 1.8% when dry and 3.1 MPa and 8.1% when wet, indicating that the films had good strength and wet stability. Films developed from grafted DDG show the potential to overcome the brittleness and poor water stability of biopolymer-based films and be useful for various applications.