• Korean Journal of Microbiology
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• v.40 no.1
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• pp.43-48
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• 2004

Bacillus megaterium F7-1 producing keratinolytic protease was isolated from decayed chicken feather. The optimal culture conditions for the production of keratinolytic protease by B. megaterium F7-1 were investigated. The composition of optimal medium for the keratinolytic protease was 0.2% glucose, 0.8% skim milk, 0.05% NaCl, 0.01 % $(K_2HPO_4$, 0.02%, $(KH_2PO_4$ and 0.01 % $MgCl_2$. Especially, skim milk was found to be the most effective compound in keratinolytic protease production. The optimal temperature and initial pH were 6.5 and $25^{\circ}C$, respectively. The keratinolytic protease production under optimal condition reached a maximum of 269 U/ml after 5 days of cultivation. B. megaterium F7-1 degraded 98% of the feather used in the optimized medium within 6 days.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.134-141
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• 2001

A bacterial strain KP-364 producing extracellular keratinolytic protease was isolated from the soil of the poultry fac-tory. It was identified as Pseudomonas sp. based on its morphological and physiological characteristics, The optimal culture conditions for the production of keratinolytic protease by Pseudomonas sp. KP-364 were investigated. The composition of optimal medium for the keratinolytic protease was 2.0% glucose, 0.5% soybean meal. 0.5% $NaNO_3$ and 0.2% KCI Optimal initial pH for production of Keratinolytic protease production were 6.5 and $37^{\circ}C$ respec- tively. The keratinolytic protease production reached a maximum of 1,270 U/ml/hr after 48 hours cultivation under the optimal culture conditions.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.150-157
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• 2006

Bacillus sp. SMMJ-2 producing extracellular keratinolytic protease was isolated from the Swedish soils. The optimal culture conditions for production of keratinolytic protease by Bacillus sp. SMMJ-2 were investigated. The optimal medium compositions for the keratinolytic protease production were 0.7% $K_2HPO_4$, 0.2% $KH_2PO_4$, 1.0% fructose,1.2% soybean meal (roasted), and 0.01% $Na_2CO_3$. Optimal initial pH and temperature for the production of keratinolytic protease were 7.0 and 30$^{\circ}C$, respectively. The keratinolytic protease production showed a maximum of 105 units/ml/min after 72 hours cultivation under the optimal culture conditions.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.224-229
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• 2003

A keratinolytic protease was purified from the culture medium of Pseudomonas sp. KP-364 by use of an assay of the hydrolysis of feather keratin. Membrane ultrafiltration and DEAE-cellulose ion-exchange resin and Sephadex G-150 gel chromatographies were used to purify the enzyme. The specific activity of the purified keratinolytic protease relative to that in the original medium was approximately 72-fold high. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Sephadex G-150 chromatography indicated that the purified keratinolytic protease is monomeric and has a molecular weight of 36 kDa. The optimal pH and temperature of the keratinolytic protease activity were 6.6 and 37 C, respectively, and the keratinolytic protease was relatively stable at pH value from 3.0 to 10.0 at 37 C for 1hour. The keratinolytic protease was inhibited by EDTA and EGTA, indicating that the keratinolytic protease was a kind of metalloprotease that require Li+ for cofactor.

• Mycobiology
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• v.31 no.4
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• pp.209-213
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• 2003

Aspergillus flavus K-03 isolated from poultry forming soil in Korea was studied for its ability to produce extracellular proteases on basal medium containing 2%(w/v) chicken feathers. The fungus was observed to be a potent producer of such enzymes. Keratinolytic enzyme secretion was the best at 15 days of incubation period at pH 9 and temperature $40^{\circ}C$. No relationship existed between the enzyme yield and increase of biomass. Enzyme production was suppressed by exogenous sugars in descending order arabinose>maltose>mannose>fructose. But glucose did not influence the enzyme activity. The keratinolytic enzyme released by the fungus demonstrated the ability to decompose keratin substrates as chicken feather when exogenous glucose was present. The keratinolytic activity was inhibited by $HgCl_2$ and serine-protease inhibitors such as phenymethylsulfonyl fluoride(100%), chymostain(88%), crystalline soybean trypsin inhibtor(80%), antipain(45%) and aprotinin(40%), and was not by cystein-protease and aspartyl-protease inhibitors. The enzyme activity is only partially inhibited by metallo-protease inhibitor. Thus, the enzyme secreted by A. flavus K-03 belongs to the alkaline serine-type protease.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.7-14
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• 2006

Feather, generated in large quantities as a byproduct of commercial poultry processing, is almost pure keratin, which is not easily degradable by common professes. Four strains, SMMJ-2, FL-3, NO-4 and RM-12 were isolated from soil for production of extracellular keratinolytic protease. They were identified as Bacillus sp. based on their morphological and physiological characteristics. They shown high protease activity on 5.0% skim milk agar medium and produced a substrate like mucoid on keratin agar medium. Bacillus sp. SMMJ-2 had a faster production time for producing keratinolytic protease than other strains. This strain did not completely degrade whole chicken feather for five days in basal medium but completely degraded whole chicken feather when supplied with nitrogen source for 40hours in keratinolytic producing medium ($0.7%\;K_{2}HPO_{4},\;0.2%\;KH_{2}PO_{4},\;0.1%$ fructose, 1.2% whole chicken feather, $0.01%\;Na_{2}CO_3$, pH 7.0). When supplied with chicken feather as nitrogen source, keratinolytic protease activity was 89 units/ml/min. When soybean meal was used as nitrogen source, the keratinolytic protease production reached a maximum of 106 units/ml/min after 48 hours under $30^{\circ}C$, 180 agitation. To isolate the keratinolytic protease, the culture filtrate was precipitated with $(NH_4)_{2}SO_4$ and acetone. The recovery rate of keratinolytic protease was about 96% after treatment with 50% acetone. The enzyme was stable in the range of $30{\sim}50^{\circ}C$ and pH $6.0{\sim}12.0$.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.343-350
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• 2009

This study was carried out to investigate the possibility to utilize feather meal by bacterial strains. A bacterial strain SE-103 producing keratinolytic enzyme was isolated from the soil of the poultry slaughterhouses. It was identified as Bacillus sp. by judging from its morphological and physiological characteristics. Subsequently the optimal culture conditions for the production of keratinolytic protease by Bacillus sp. SE-103 were investigated. The composition of optimal medium was 3.0% glucose, 0.4% urea, 0.2% $NaNO_3$, and 0.15% KCl. In addition, optimal initial pH and temperature were 6.0 and $35^{\circ}C$, respectively.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.472-476
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• 2005

The present study was untaken to assess the capacity of Bacillus pumilis KHS-1 to grow on chicken flour and to prepare feather digest as fertilizer. To increase keratinolytic activity, the addition of cysteine (5.0 mM) showed the highest keratinolytic activity (245 unit) among the reducing agents tested. The production of soluble protein (feather digests) paralleled the tendency to the production of keratinolytic protease. In the growth curve of B. pumilis KHS-1 at $30^{\circ}C$ in the feather medium with 5 mM cysteine, the maximum keratinolytic activity of B. pumilis was about 161 units/ml after 84 h of incubation. The maximum enzyme activities were observed at the late logarithmic growth phase, and remained thereafter with little changes. Using 27-day plant growth assays on carrot and Chinese cabbage, feather digests and reference fertilizer were compared. In terms of the length and the weight of the above-ground vegetations, feather digests showed the same effect as that of the fertilizer. Therefore, our investigation shows that the feather digests can be used in agriculture.

• 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.16 no.10
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• pp.1203-1208
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• 2007

Feathers are produced in huge quantities as a waste product at commercial poultry processing plants. Since feathers are almost pure keratin protein, feather wastes represent an alternative to more expensive dietary ingredients for animal feedstuffs. Generally they become feather meal used as animal feed after undergoing physical and chemical treatments. These processes require significant energy and also cause environmental pollutions. Therefore, biodegradation of feather by microorganisms represents an alternative method to prevent environment contamination. The aim of this study was to investigate cultural conditions affecting keratinolytic protease production by Bacillus pumilus RS7. We also assessed the nutritive value of microbial and alkaline feather hydrolysates, The composition of optimal medium for the keratinolytic protease was fructose 0.05%, yeast extract 0.3%, NaCl 0.05%, K2HPO4 0.03%, KH2PO4 0.04% and MgCl2 6H2O 0.01%, respectively. The optimal temperature and initial pH was $30^{\circ}C$ and 9.0, respectively. The keratinolytic protease production under optimal condition reached a maximum after 18 h of cultivation. Total amino acid content of feather hydrolysates treated by NaOH and B. pumilius RS7 was $113.8\;{\mu}g/ml$ and $504.9\;{\mu}g/ml$, respectively. Essential amino acid content of feather hydrolysates treated by NaOH and B. pumilius RS7 was $47.2\;{\mu}g/ml$ and $334.0\;{\mu}g/ml$, respectively. Thus, feather hydrolysates have the potential for utilization as an ingredient in animal feed.