• Journal of Microbiology and Biotechnology
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• 제28권2호
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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.

• 한국환경과학회지
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• 제19권9호
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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%).

• 한국환경과학회지
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• 제21권2호
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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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• 제10권2호
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• pp.210-214
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• 1997

Ruminal degradation characteristics and intestinal availability of crude protein (CP) in four animal-origin feeds (fish meal, meat meal, viscera meal, feather meal) were estimated by mobile nylon bag technique. Three ruminally and duodenally cannulated Holstein dairy cows (average body wt. 550kg) fed a diet containing 40% concentrate and 60% orchard grass hay on a dry matter (DM) basis. Assuming that the outflow rate of diet in rumen is 5% per hour (k =0.05), contents of quickly degradable CP (QDP), slowly degradable CP (SDP), and undegradable CP (UDP) in the rumen were 27.6%, 9.4%, 63.0% for fish meal, 34.3% 28.1%, 37,6% for meat meal, 43.9%, 12.5%, 43.6% for viscera meal, and 14.4%, 15.8%, 69.8% for feather meal, respectively. Intestinal CP degradability was 51.0% for fish meal, 27.2% for meat meal, 37.9% for viscera meal and 56.2% for feather meal. Available UDP in the intestinal tract was contained 288 g, 217 g, 246 g and 423 g per kilogram DM of diet in fish meal, meat meal, viscera meal and feather meal, respectively.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.303-309
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• 2012

Keratinases are of particular interest because of their action on insoluble keratins and generally on a broad range of protein substrates. Alkalophilic and neutrophilic actinomycete strains isolated from different soil samples, rich in keratinaceous substances were screened for keratinolytic activity. An alkalophilic isolate, TBG-S13A5, was found to possess good keratinolytic activity and was able to utilize feather as the sole carbon and nitrogen source. TBG-S13A5 exhibited an off-white aerial mass color with a rectus-flexibilis type of spore chain. The morphological, microscopical and biochemical characters were comparable with that of Streptomyces albidoflavus. Fatty acid methyl ester profiling (FAME) and 16S rDNA sequence analysis confirmed its identity as a strain of S. albidoflavus. Under submerged fermentation conditions, maximum protease production was recorded on the $5^{th}$ day of incubation at $30^{\circ}C$, using basal broth of pH 9.0 with 0.25% (w/v) white chicken feather. This strain could affect feather degradation when the initial pH was 8 and above and maximum protease production was recorded when the initial pH was around 10.5. The effectiveness of the crude enzyme in destaining and leather dehairing were also demonstrated.

• 한국환경과학회지
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• 제19권10호
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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.

• 미생물학회지
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• 제46권1호
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• pp.86-92
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• 2010

양계장 부산물 시료로부터 우모 분해세균 31균주를 분리하였다. 수집된 우모 분해세균에 대해 16S rRNA 염기서열을 해석하여 계통학적 특성을 검토한 결과, Firmicutes (21균주), ${\gamma}$-proteobacteria (4균주), Actinobacteria (4균주) 그리고 Bacteroidetes (2균주) 계통군에 속하는 다양한 세균이 확보되었다. 우모 분해세균 중 우모 분해율이 75-90% 이상인 우수균주 Chryseobacterium sp. FBF-7, Stenotrophomonas maltophilia FBS-4 그리고 Lysinibacillus sp. FBW-3를 최종 선발하였다. 이들 균주를 이용한 생물학적 분해법과 Ca(OH)2를 이용한 화학적 분해법에 의해 추출된 아미노산의 특성을 비교한 결과, Chryseobacterium sp. FBF-7에 의해 추출된 총 아미노산 함량이 1661.6 ${\mu}mol$/ml로 선발 균주 중 가장 높게 나타났으며, 화학적 분해법에 의해 추출된 총 아미노산 함량과 유사하였다. Chryseobacterium sp. FBF-7에 의해 생성된 필수 아미노산 함유량은 619.3 ${\mu}mol$/ml로 총 아미노산의 37%를 함유하였으며, 화학적 분해법에 의한 경우, 596.9 ${\mu}mol$/ml의 필수 아미노산을 생산하여 총 아미노산 함유량의 32%를 차지하는 것으로 나타났다. Chryseobacterium sp. FBF-7에 의해 추출된 아미노산의 조성을 검토한 결과, valine, glutamic acid, aspartic acid, glycine 그리고 proline이 주요 아미노산이었으며, 특히 aspartic acid, threonine, serine, cysteine 그리고 tyrosine이 화학적 추출법보다 더 높게 추출되는 특징을 나타내었다.

• Journal of Animal Science and Technology
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• 제44권1호
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• pp.105-112
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• 2002

동물성 부산물 사료(우모분, 우지박, 내장분)단백질의 반추위내 분해특성과 하부장기내 이용성에 대한 열처리 효과를 구명하기 위하여 반추위와 십이지장에 누관이 장착된 Holstein 건유우 3두를 공시하였다. 시험사료에 대한 열처리는 149$^{\circ}C$가 유지되는 oven에서 4시간동안 처리한 후, 1 mm체를 통과시켰다. 시험사료의 반추위내 분해특성은 발효시간별 분해율에서 비선형회귀식을 유도하여 구하였고, 사료단백질의 하부장기내 이용성은 mobile nylon bag기법으로 추정되었다. 농후사료와 orchard grass를 60:40의 비율로 급여하였으며, 물과 mineral block은 자유섭취토록 하였다. 조단백질의 반추위내 유효분해도(k=0.05) 및 하부장기내 소실율에 있어서 우모분은 각각 30.2% 및 56.2%, 우지박은 75.0% 및 18.6% 그리고 내장분은 56.4% 및 37.9%였다. 시험사료에 대한 열처리효과에 있어서 조단백질의 반추위내 유효분해도는 우모분과 내장분은 증가하였으나 우지박은 감소되었고(P$<$0.05), 하부장기내 조단백질 소실율에서는 우지박은 증가된 반면, 우모분과 내장분은 감소되어(P$<$0.05) 상반되는 결과를 나타내었다. 반추위 미분해 사료단백질의 하부장기내 이용율은 우모분, 우지박 및 내장분에 대해서 각각 80.4%, 83.8% 및 86.9%였으며, 열처리를 함으로써 우모분과 우지박은 각각 94.0% 및 91.3%로 향상되었으나, 내장분은 76.5%로 낮아졌다(P$<$0.05).

• Mycobiology
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• 제33권2호
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• pp.121-123
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• 2005

Extracellular keratinase isolated from Aspergillus flavus K-03 was immobilized on calcium alginate. The properties and reaction activities of free and immobilized keratinase with calcium alginate were characterized. The immobilized keratinase showed proteolytic activity against soluble azo-casein and azo-keratin, and insoluble feather keratin. Heat stability and pH tolerance of keratinase were greatly enhanced by immobilization. It also displayed a higher level of heat stability and an increased tolerance toward alkaline pHs compared with free keratinase. During the durability test at $40^{\circ}C$, 48% of the original enzyme activity of the immobilized keratinase was remained after 7 days of incubation. The immobilized keratinase exhibited better stability, thus increasing its potential for use in industrial application.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2190-2198
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• 2017

Thermoactinomyces sp. strain YT06 was isolated from poultry compost and observed to degrade integral chicken feathers completely at $60^{\circ}C$, resulting in the formation of 3.24 mg/ml of free amino acids from 50 ml of culture containing 10 g/l chicken feathers. Strain YT06 could grow and secrete keratinase using feather as the only carbon and nitrogen sources without other supplement, but complementation of 10 g/l sucrose and 4 g/l $NaNO_3$ increased the production of the keratinolytic enzyme. The maximum protease activity obtained was 110 U/ml and for keratinase was 42 U/ml. The keratinase maintained active status over a broad pH (pH 8-11) and temperature ($60-75^{\circ}C$). It was inhibited by serine protease inhibitors and most metal ions; however, it could be stimulated by $Mn^{2+}$ and the surfactant Tween-20. A reductive agent (${\beta}$-mercaptoethanol) was observed to cleave the disulfide bond of keratin and improve the access of the enzyme to the keratinaceous substrate. Zymogram analysis showed that strain YT06 primarily secreted keratinase with a molecular mass of approximately 35 kDa. The active band was assessed by MALDI-TOF mass spectrometry and was observed to be completely identical to an alkaline serine protease from Thermoactinomyces sp. Gus2-1. Thermoactinomyces sp. strain YT06 shows great potential as a novel candidate in enzymatic processing of hard-to-degrade proteins into high-value products, such as keratinous wastes.