• Korean Journal of Microbiology
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• v.46 no.1
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• pp.86-92
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• 2010

Thirty-one chicken feather-degrading bacteria were isolated from wasted feather, compost and wastewater in a chicken farm. These isolates were categorized as Firmicutes (21 strains), ${\gamma}$-proteobacteria (4 strains), Actinobacteria (4 strains), and Bacteroidetes (2 strains) by 16S rRNA gene sequence analysis. We examined the feather-degrading isolates for degradation in the 2% of chicken feather meal. The strain Chryseobacterium sp. FBF-7, Stenotrophomonas maltophilia FBS-4, and Lysinibacillus sp. FBW-3 were selected as a keratinolytic protein degrading bacteria which showed the highest feather degradation of 75-90%. The characteristics of amino acids extracted from chicken feather meal by using keratinolytic protein degrading isolates and chemical method with $Ca(OH)_2$ were analyzed. Total amino acid content of strain Chryseobacterium sp. FBF-7 was 1,661.6 ${\mu}mol$/ml, which was the highest and it was similar with chemical method. And essential amino acid content of total amino acid was thirty-seven percent (619.3 ${\mu}mol$/ml) and 596.9 ${\mu}mol$/ml for keratinolytic protein degrading isolates and chemical method, respectively. The major amino acids were valine, glutamic acid, aspartic acid, glycine, and proline by the strain Chryseobacterium sp. FBF-7 and especially, higher contents of aspartic acid, threonine, serine, cysteine, and tyrosine were detected compared with chemical method.

• Journal of Environmental Science International
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• v.16 no.9
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• pp.1103-1109
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• 2007

The aim of this study was to isolate mesophilic chicken feather-degrading bacteria and to evaluate feather hydrolysate as alternative biofertilizer. Isolate RS7 was isolated from compost and identified as Bacillus pumilus according to API analysis and l6S rDNA sequencing analysis. Chicken feathers were completely degraded after 5 days of cultivation at $30^{\circ}C$. Feather hydrolysate treated by B. pumilius RS7 positively influenced Helianthus sannuus L. (sunflower) growth (e.g. growth rate, number and dry weight of leave, and flowering rate). These results suggest that feather hydrolysate prepared using B. pumilius RS7 could successfully be used as alternative biofertilizer, thereby reducing the environmental impact of feather waste from the poultry industry.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1337-1343
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• 2007

The aim of this study was to isolate chicken feather-degrading bacteria with high keratinolytic activity and to investigate cultural conditions affecting keratinolytic enzyme production by a selected isolate. A chicken feather-degrading bacterial strain CH3 was isolated from poultry wastes. Isolate CH3 degraded whole chicken feather completely within 3 days. On the basis of phenotypical and 16S rDNA studies, isolate CH3 was identified as Bacillus thuringiensis CH3. This strain is the first B. thuringiensis described as a feather degrader. The bacterium grew with an optimum at pH 8.0 and $37^{\circ}C$, where maximum keratinolytic activity was also observed. The composition of optimal medium for keratinolytic enzyme production was feather 0.1%, sucrose 0.7%, casein 0.3%, $K_2HPO_4$ 0.03%, $KH_2PO_4$ 0.04%, $MgCl_2$ 0.01% and NaCl 0.05%, respectively. The keratinolytic enzyme had a pH and temperature optima 9.0 and $45^{\circ}C$, respectively. The keratinolytic activity was inhibited ethylenediaminetetraacetic acid, phenylmethylsulfonyl fluoride, and metal ions like $Hg^{2+},\;Cu^{2+}\;and\;Zn^{2+}$. The enzyme activated by $Fe^{2+}$, dithiothreitol and 2-mercaptoethanol.

• Journal of Environmental Science International
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• v.21 no.2
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• pp.253-261
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• 2012

We isolated and characterized novel duck feather-degrading bacteria producing keratinase. Twelve strains were isolated from soil and faces at poultry farm, and decayed feathers. They were identified as Bacillus methylotrophicus, Pseudomonas geniculata, Pseudomonas hibiscicola, Exiquobacterium profundum, Bacillus pumilus, Bacillus amyloliquefaciens, Chryseobacterium indologenes, Bacillus thuringiensis, Thermomonas koreensis, respectively, by phenotypic characters and 16S rRNA gene analysis. Generally, the level of keratinase production was not proportional to feather degradation rate. The highest keratinolytic activity was observed in the culture inoculated with Chryseobacterium indologenes D27. Although all strains did not degrade human hair, strains tested effectively degraded chicken feather(53.8-91.4%), wool(40.4-93.0%) and human nail (51.0-82.9%). These results suggest that strains isolated could be not only used to improve the nutritional value of recalcitrant feather waste but also is a potential candidate for biotechnological processes of keratin hydrolysis.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1769-1774
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• 2001

Bacillus licheniformis strains L-25 and PWD-1 are two thermophilic feather-degrading bacteria. Despite isolated from different environmental conditions, they were both capable of breaking down chicken feathers and growing in a medium in which feather was the only source of carbon and nitrogen. A 1.46-kb keratinase gene (ker B) was isolated from strain L-25 by a polymerase chain reaction (PCR) using L-25 genomic DNA as templates. Sequencing results reveal that ker B shares great sequence identity with a previously published keratinase gene of B. licheniformis PWD-1 (ker A). Only two amino acids differences were found in the deduced amino acid sequence between the keratinases from L-25 and PWD-1. However several nucleotide changes were found upstream of the putative promoter region. Protease inhibition studies indicated that neutral protease activity accounted for approximate 25 to 30% of total extracellular proteolytic activity produced by strain L-25 in the feather medium. In contrast, no measurable neutral protease activity was produced by strain PWD-1 in the feather medium. When glucose (1%), a common catabolic repressor, was added into the feather medium, L-25 was still able to grow and produce keratinase. Strain PWD-1 produced no neutral protease activity and its growth was severely inhibited in the feather medium containing glucose. L-25 produced an enhanced level of keratinase in the feather medium in comparison with PWD-1.

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1307-1314
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• 2010

This study was conducted to isolate and characterize a novel feather-degrading bacterium producing keratinase activity. A strain K9 was isolated from soil at poultry farm and identified as Xanthomonas sp. K9 by phenotypic characters and 16S rRNA gene analysis. The cultural conditions for the keratinase production were 0.3% fructose, 0.1% gelatin, 0.04% $K_2HPO_4$, 0.06% $KH_2PO_4$, 0.05% NaCl and 0.01% $FeSO_4$ with an initial pH 8.0 at $30^{\circ}C$ and 200 rpm. In an optimized medium containing 0.1% chicken feather, production yield of keratinase was approximately 8-fold higher than the yield in basal medium. The strain K9 effectively degraded chicken feather meal (67%) and duck feather (54%), whereas human nail and human hair showed relatively low degradation rates (13-22%). Total free amino acid concentration in the cell-free supernatant was about 25.799 mg/l. Feather hydrolysate produced by the strain K9 stimulated growth of red pepper, indicating Xanthomonas sp. K9 could be not only used to increase the nutritional value of chicken feather but also a potential candidate for the development of natural fertilizer applicable to crop plant soil.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.314-322
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• 2018

Bacillus subtilis 8 is highly efficient at degrading feather keratin. We observed integrated feather degradation over the course of 48 h in basic culture medium while studying the entire process with scanning electron microscopy. Large amounts of ammonia, sulfite, and $\text\tiny{L}$-cysteic acid were detected in the fermented liquid. In addition, four enzymes (gamma-glutamyltranspeptidase, peptidase T, serine protease, and cystathionine gamma-synthase) were identified that play an important role in this degradation pathway, all of which were verified with molecular cloning and prokaryotic expression. To the best of our knowledge, this report is the first to demonstrate that cystathionine gamma-synthase secreted by B. subtilis 8 is involved in the decomposition of feather keratin. This study provides new data characterizing the molecular mechanism of feather degradation by bacteria, as well as potential guidance for future industrial utilization of waste keratin.

• Journal of Life Science
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• v.14 no.2
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• pp.229-234
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• 2004

Feathers, which are almost pure keratin protein, are produced in large amounts as a waste by-product at poultry-processing plants. Keratinolytic enzymes may have important uses in biotechnological processes involving keratin-containing wastes from poultry and leather processes. In this study, screening and identification of keratin-degrading bacteria were investigated. Five keratin-degrading bacterial strains (F3-1, F3-4, F7-1, C1-1, C1-2) were isolated from compost and decayed chicken feather. On the basis of morphological, physiological studies, and Biolog system, all isolates were identified as the genus Bacillus. Among them, the strain F7-1 had the highest feather-degrading activity and was selected for further taxonomical study. Phylogenetic analysis of strain F7-1 based on comparison of 165 rDNA sequences revealed that this strain is closely related to Bacillus megaterium.

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1077-1082
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• 2010

This study was performed to investigate the nutritional conditions controlling keratinase activity in Bacillus megaterium F7-1. B. megaterium F7-1 produced keratinase using chicken feather as a sole source of carbon, nitrogen and sulfur. Addition of the feather medium with glucose enhanced keratinase production (68.9 U/ml), compared to control without glucose (63.2 U/ml). The synthesis of keratinase was repressed by addition of $NH_4Cl$ in B. megaterium F7-1. The highest keratinase production (70.9 U/ml) was obtained with the feather medium containing glucose and $MgSO_4{\cdot}7H_2O$. Keratinase was produced in the absence of feather (4.9 U/ml), indicating its constitutive synthesis. Feather degradation resulted in free SH group formation. B. megaterium F7-1 effectively degraded chicken feather meal (86%), whereas duck feather, human nail, human hair and sheep wool displayed relatively low degradation rates (8-34%).

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.315-318
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• 2005

The effects of inorganic salts and feather concentrations on pretense production by Bacillus megaterium F7-1 were investigated. Pretense production was dependent on the presence of phosphates in the medium. Supplementation of medium with calcium ion slightly increased protease production. The highest protease production was obtained at $1.4\%$ feather. The optimal medium contained $2.0\%$ glucose, $0.8\%$ skim milk, $0.06\%\;K_{2}HPO_{4}\%,\;0.04\%\;KH_{2}PO{4},\;0.06\%\;NaCl,\;0.03\%\;MgCl_{2}\cdot6H_{2}O,\;0.002\%\;CaCl_{2}\cdot2H_{2}O,\;and\;1.4\%$ whole feather. By using this optimized medium, increased production of the protease was achieved compared with the cases of using basal medium.