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The molecular structure of the detailed composition of hair, modified from Yang et al. (2014) and Banerjee et al. (2014). Permission for re-publishing has been received from copyright owners
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Discovery of keratin-degrading enzymes from fungi and bacteria has primarily focused on finding one protease with efficient keratinase activity. Recently, an investigation was conducted of all keratinases secreted from a fungus known to grow on keratinaceous materials, such as feather, horn, and hooves. The study demonstrated that a minimum of thre...
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The present study aim was to isolate keratinolytic bacteria from the soil contaminated with poultry waste. From amongst nine bacterial keratinase producing isolates were found. The BML5 isolate was identified as Bacillus subtilis based on biochemical characterization and 16S rRNA Ribotyping. B. subtilis BML5 showed maximal keratinase activity at 37...
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... Keratinolytic dermatophyte proteases have a relevant role in the pathogenesis of dermatophytosis. Therefore, dermatophytes need to express secreted proteases to break down keratins in human tissues to exploit this nitrogen source and survive [42]. ...
The ability of dermatophytes to develop biofilms is possibly involved in therapeutic failure because biofilms impair drug effectiveness in the infected tissues. Research to find new drugs with antibiofilm activity against dermatophytes is crucial. In this way, riparins, a class of alkaloids that contain an amide group, are promising antifungal compounds. In this study, we evaluated the antifungal and antibiofilm activity of riparin III (RIP3) against Trichophyton rubrum, Microsporum canis, and Nannizzia gypsea strains. We used ciclopirox (CPX) as a positive control. The effects of RIP3 on fungal growth were evaluated by the microdilution technique. The quantification of the biofilm biomass in vitro was assessed by crystal violet, and the biofilm viability was assessed by quantifying the CFU number. The ex vivo model was performed on human nail fragments, which were evaluated by visualization under light microscopy and by quantifying the CFU number (viability). Finally, we evaluated whether RIP3 inhibits sulfite production in T. rubrum. RIP3 inhibited the growth of T. rubrum and M. canis from 128 mg/L and N. gypsea from 256 mg/L. The results showed that RIP3 is a fungicide. Regarding antibiofilm activity, RIP3 inhibited biofilm formation and viability in vitro and ex vivo. Moreover, RIP3 inhibited the secretion of sulfite significantly and was more potent than CPX. In conclusion, the results indicate that RIP3 is a promising antifungal agent against biofilms of dermatophytes and might inhibit sulfite secretion, one relevant virulence factor.
... Keratin is, after cellulose and chitin, the third most abundant polymer in nature. The robust structure of keratin constitutes the outer protection of many kinds of animals and keeps keratin stable even against microbial attack in nature [11]. Bovine horns, the structural component of which is keratin, are hard to decompose or recycle after they are wasted from slaughter house and usually end up in incinerators. ...
Efficient removal of dyes from wastewater has become an urgent issue due to the rapid industrial development and increasing health concern. Here, micro-/mesoporous heteroatom-doped biochars (BHBs) were prepared from waste bovine horn by controlled pyrolysis. The BHB that had undergone a pre-oxidation reaction before pyrolysis has honeycomb-like porous structure with high specific surface area of 2447.41 m ² g − 1 and the pore size of lower than 5 nm. The tunable porous structure of the biochar could shorten the travel distance of dye molecules from external surface of biochar to inner surface of pores. And the heteroatoms could enhance the interactions, including electrostatic interaction and hydrogen bonding interaction between carbon surface and methylene blue molecules. For adsorption of methylene blue, the BHB exhibited high adsorption capacity of 1720.92 mg g − 1 at 30 ℃ and could reach a removal efficiency of near 100% in 0.5 h. The excellent adsorption performance of BHB for dye makes it a potential adsorbent for wastewater purification.
... Global poultry production was over 130 million tons in 2019 [31], generating tons of slow-to-degrade keratinous wastes with overwhelmingly high pollution potential. Keratinous wastes have also been considered the world's third most abundant natural biopolymer [2,30]. In recent times, the acute need to mitigate the deleterious effects of keratinous wastes on the environment has engendered an explosion in research targeted at identifying new and potent keratinolytic microbes and peptidases with potential for environmental and other biotechnological applications. ...
In recent times, robust green technological developments have advanced the goal of a circular economy by minimizing waste generation. The study was undertaken to explore the keratinolytic activity of chicken feather-degrading bacteria from South African soil. Isolates coded as SSN-01 and HSN-01 were identified as Bacillus sp. NFH5 and Bacillus sp. FHNM and their sequences were deposited in GenBank, with accession numbers MW165830.1 and MW165831.1, respectively. Extracellular enzyme production and thiol group generation by Bacillus sp. NFH5 peaked at 120 h with 1879.09 ± 88.70 U/mL and 9.49 ± 0.78 mM, respectively. Glutamic acid (4.44%), aspartic acid (3.50%), arginine (3.23%), glycine (2.61%), serine (2.08%), and proline (2.08%) were relatively higher in concentration. Keratinase (KerBAN) activity was highest at pH 8.0 and 90 °C but was inhibited by both EDTA and 1,10-phenanthroline. In addition, the keratinase-encoding gene (kerBAN) accessioned OK033360 had 362 amino acid residues, with molecular weight and theoretical isoelectric point of 39 kDa and 8.81, respectively. Findings from this study highlight the significance of Bacillus sp. NFH5 in the bio-recycling of recalcitrant keratinous wastes to protein hydrolysates – potential dietary supplements for livestock feeds. The properties of KerBAN underscore its application potential in green biotechnological processes.
... Interestingly, the LPMOs AA11 genes were also found in the genome of the dermatophytic fungi [102]. It was proposed that some of these enzymes could be involved in keratin degradation [102,103], either by breaking the glycosylation bonds in the noncoiled head-structure of keratin filaments or by a reaction on tyrosine [103], but no experimental data are currently available to support this hypothesis. ...
... Interestingly, the LPMOs AA11 genes were also found in the genome of the dermatophytic fungi [102]. It was proposed that some of these enzymes could be involved in keratin degradation [102,103], either by breaking the glycosylation bonds in the noncoiled head-structure of keratin filaments or by a reaction on tyrosine [103], but no experimental data are currently available to support this hypothesis. ...
The recovery of plant mineral nutrients from the bio-based value chains is essential for a sustainable, circular bioeconomy, wherein resources are (re)used sustainably. The widest used approach is to recover plant nutrients on the last stage of biomass utilization processes-e.g., from ash, wastewater, or anaerobic digestate. The best approach is to recover mineral nutrients from the initial stages of biomass biorefinery, especially during biomass pre-treatments. Our paper aims to evaluate the nutrient recovery solutions from a trans-sectorial perspective, including biomass processing and the agricultural use of recovered nutrients. Several solutions integrated with the biomass pre-treatment stage, such as leaching/bioleaching, recovery from pre-treatment neoteric solvents, ionic liquids (ILs), and deep eutectic solvents (DESs) or integrated with hydrothermal treatments are discussed. Reducing mineral contents on silicon, phosphorus, and nitrogen biomass before the core biorefinery processes improves processability and yield and reduces corrosion and fouling effects. The recovered minerals are used as bio-based fertilizers or as silica-based plant biostimulants, with economic and environmental benefits.
... In this context, the use of feather-based keratin as feed for livestock is a very promising alternative to valorize this type of waste. Indeed, keratin is the third most abundant polymer in nature after cellulose and chitin (Lange et al. 2016). Industrial methods of feather degradation (to generate flours) consume a large amount of energy and reduce the general quality of the proteins. ...
Keratin-rich wastes, mainly in the form of feathers, are recalcitrant residues generated in high amounts as by-products in chicken farms and food industry. Polylactic acid (PLA) is the second most common biodegradable polymer found in commercial plastics, which is not easily degraded by microbial activity. This work reports the 3.8-Mb genome of Bacillus altitudinis B12, a highly efficient PLA- and keratin-degrading bacterium, with potential for environmental friendly biotechnological applications in the feed, fertilizer, detergent, leather, and pharmaceutical industries. The whole genome sequence of B. altitudinis B12 revealed that this strain (which had been previously misclassified as Bacillus pumilus B12) is closely related to the B. altitudinis strains ER5, W3, and GR-8. A total of 4056 coding sequences were annotated using the RAST server, of which 2484 are core genes of the pan genome of B. altitudinis and 171 are unique to this strain. According to the sequence analysis, B. pumilus B12 has a predicted secretome of 353 proteins, among which a keratinase and a PLA depolymerase were identified by sequence analysis. The presence of these two enzymes could explain the characterized PLA and keratin biodegradation capability of the strain.
... It is also resistant to common proteolytic enzymes such as pepsin and trypsin [16]. Different types of keratins exist in nature, and they are characterized by their secondary structure and sulfur content [15,17]. According to their secondary structure, keratins are categorized into alpha and beta keratins. ...
Fervidobacterium pennivorans subsp. keratinolyticus subsp. nov. strain T was isolated from a terrestrial, high-altitude hot spring in Tajikistan. This strain is an obligate anaerobic rod and their cells occur singly, in pairs, or as short chains under the optimal growth conditions of a temperature of 65 °C and pH 6.5, with peptone, glucose, and galactose as the preferred substrates. The minimum generation time of this strain is 150 min. Strain T can efficiently degrade feather keratin at 65–75 °C; this unusual feature is also exhibited by a few other members of the Fervidobacterium genus. The total genome size of this bacterial strain is 2,002,515 base pairs, with a C + G content of 39.0%. The maximum digital DNA–DNA hybridization (dDDH) value of 76.9% was observed on comparing the genome of this strain with that of Fervidobacterium pennivorans type strain DSM9078. This study describes the physiological and genomic properties of strain T, with an emphasis on its keratinolytic power and differences from other members of the genus Fervidobacterium.
... Therefore, understanding the seldom explored physical and chemical characteristics of keratin is crucial to improving its extraction and use. For instance, posttranslational modifications can be used for structural alteration to yield keratins of different Mw with improved bioaccessibility for enzymatic activity (Bragulla & Homberger, 2009;Lange et al., 2016). ...
... The degradation of keratinous materials by microbes relies on the synergistic activity of several enzymes. For instance, endoprotease (S8), oligopeptidase/metalloprotease (M3), and an exoprotease (M28) have been identified in a nonpathogenic fungus Onygena corvina (Lange et al., 2016). ...
The growing global population and lifestyle changes have increased the demand for specialized diets that require protein and other essential nutrients for humans. Recent technological advances have enabled the use of food bioresources treated as waste as additional sources of alternative proteins. Sheep wool is an inexpensive and readily available bioresource containing 95%–98% protein, making it an outstanding potential source of protein for food and biotechnological applications. The strong structure of wool and its indigestibility are the main hurdles to achieving its potential as an edible protein. Although various methods have been investigated for the hydrolysis of wool into keratin, only a few of these, such as sulfitolysis, oxidation, and enzymatic processes, have the potential to generate edible keratin. In vitro and in vivo cytotoxicity studies reported no cytotoxicity effects of extracted keratin, suggesting its potential for use as a high‐value protein ingredient that supports normal body functions. Keratin has a high cysteine content that can support healthy epithelia, glutathione synthesis, antioxidant functions, and skeletal muscle functions. With the recent spike in new keratin extraction methods, extensive long‐term investigations that examine prolonged exposure of keratin generated from these techniques in animal and human subjects are required to ascertain its safety. Food applications of wool could improve the ecological footprint of sheep farming and unlock the potential of a sustainable protein source that meets demands for ethical production of animal protein.
... From the soil of the ostrich farm, 22 bacterial isolates were isolated. However, on the basis of proteolytic ability, only three isolates were selected and their cultural and morphological identification was carried out following Cappuccino and Sherman [20,23]. It was noticed that the bacterial isolate SNO1 showed whitecolored colonies of circular form with undulated margins and umbonate elevation. ...
... However, only three bacterial isolates showed feather degradation. This study is in line with the findings of Lang et al. [23] who reported that the soil associated with poultry farms harbours a large bacterial fauna that is also involved in biodegradation. Similarly, Veenayohini and Sangeetha [24] reported both the soil and feather samples; acted as a natural habitat for a wide variety of bacterial species. ...
Keratinolytic microorganisms have the capacity to biosynthesize particular keratinases and determine their prospective application in poultry waste management. Hence, the objective of this study was to utilize keratinolytic microbes for the degradation of poultry waste. For this purpose, the feathers of common ostrich (Struthio camelus) were collected, scattered along the surrounding dry soil, from a private ostrich farm in Kasur, Pakistan. Bacteria were isolated by using culture enrichment techniques and screened for their proteolytic activity on skim milk agar. The isolates were characterized clonially, morphologically, and biochemically and labeled as SNO1, SNO2, and SNO3, respectively. The effects of varied pH and temperatures were recorded on bacterial growth and feather degradation. It was noticed that the bacterial cell densities and feather degradation were high at 50˚C and pH 8.0, as compared to the rest of the culture conditions. Visual observations were made using a stereomicroscope. The maximum feather degradation in the form of white powdery mass was noticed at fourth (4th) week. The protein content of Struthio camelus feathers was determined as 6.5 mg/100 ml after degradation. Taken together, the authors concluded that the isolated strains were capable of feather degradation and can be used in poultry waste management.
... A considerable amount of biowastes in the form of avian feathers, human hair, animal wool, furs, and horns having keratin as the main constituent, a polymer recalcitrant to physical and chemical treatment and hardly degraded by proteolytic enzymes [38,39], are discharged into the environment without being getting benefited of its large amount of protein and amino acids. Chicken feathers are made of supercoiled polypeptide chains containing various amino acids connected through cross-linked disulfide bonds, which grant rigidity to the feathers. ...
... Avian feathers are beta keratinous polymer material formed of supercoiled polypeptide chains and cross-linked with disulfide bonds. The polymer is obstinate resistant to physical and chemical treatment and is hard to degrade by proteolytic enzymes, which would provide a medium for microbial growth if not timely treated [38,39]. Chicken feathers constitute 8-10% of the total chicken weight and dispose of millions of tons untreated in landfills annually [40,43,53,54]. ...
The unique physical, chemical, and biological properties have attracted widespread applications in electronics, sensing, drug delivery, cancer diagnosis, and therapy. Millions of tons of biowaste are produced as chicken feathers from poultry, hair from tanneries, and horns each year and disposed of in landfills, which adds to environmental pollution. The untreated biowastes being enriched in protein serve as a medium for microbial growth and infections, an alarming threat to human survival on earth. Bacteria are the causative agents of many disorders and illnesses and are responsible for producing urease and other enzymes, which cause health disorders in humans. Here, we report a successful conversion of biowaste (chicken feathers), used as a template for the synthesis of silver (AgNP) and gold (AuNP) nanoparticles. Subsequently, the synthesized nanopar-ticles were characterized by UV-Vis spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The newly prepared AgNP and AuNP nanoparticles have spherical shapes and 3-13 nm and 4-20 nm sizes, respectively. AgNPs demonstrated an excellent Urease inhibitory potential of 99.9 with IC 50 14.2 ± 0.17 μg/mL, chicken feathers extract (CFE) 99.4% with IC 50 50.2 ± 0.98 μg/mL and standard thiourea 99.8% with IC 50 21.2 ± 1.3 μg/mL. In addition, it revealed good bactericidal applications. These synthesized nanoparticles were found stable against various parameters such as temperature, pH, and salinity. These outcomes proposed AgNPs and the biowaste extract as an eco-friendly slant for controlling the growth of Klebsiella pneumoniae and Pseudomonas aeruginosa and as potential urease inhibitors.
... Optimum temperature and pH is important parameters to define the rate of fungal growth and sporulation. Keratinous waste should be degraded because it causes disease and pollution and can easily be degraded by keratinophilic fungi because, it is tough fibrous polymer (Lange et al, 2016). In animals hair, feathers in hard and soft polymers degraded by keratinophilic fungi (Gupta and Naik, 2015). ...
Hyphomycetes includes keratinophilic, dermatophytes and non dermatophytes filamentous fungi. Keratinophilic fungi growth is effected by biotic and environmental factors. Evaluation of effect of pH and temperature as physical conditions was observed . In the present investigation the steps have been undertaken to study the effect of temperature and Ph on keratinophilic fungus Chrysosporium indicum in vitro condition. The study of fungus has specific range of favourable pH and temperature. The normal growth of chrysoporium inducing was observed between 250C to 350C, where maximum growth and speculation was observed at 30. There has been a drastic reduction in fungal growth below 100C or 150C and speculation and growth declined at above 350C. So, it is observed that between 25 0C to 350C fungal growth and sporulation occur favorably .Below 100C and above 350C did not favour the growth and reproduction of keratinophilic fungi. Effect of hydrogen ion concentration was observed particularly for Chrysosporium indicum. Favourable hydrogen ion concentration for mycelial growth was 7.00. In present study Chrysosporium indicum fungal hyphae growth was changed with pH and the maximum growth was found at the end of incubation day is about pH 7 to 7.5
