• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.178-183
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• 2005

A strain WL-2 was isolated from soil as a producer of the extracellular xylanase, which catalyzes the hydrolysis of oat spelt xylan. The strain WL-2 was identified as Streptomyces sp. on the basis of its 16S rRNA sequence, morphology, cultural and physiological properties. The xylanase of culture filtrate was the most active at $60^{\circ}C$ and pH 6.0, and retained $90{\%}$ of its maximum activity at range of pH $4.5{\~}6.5$. In order to optimize the culture medium for xylanase production, ingredients of G.S.S medium were replaced by several carbohydrates. The carbohydrates such as ${\alpha}-cellulose$, oat spelt xylan and maltose increased dramatically the xylanase productivity of Streptomyces sp. WL-2. The maximum xylanase productivity was reached to 120 U/ml in the modified medium containing $1{\%}\;\alpha-cellulose$ and $1\%}$ maltose.

• BMB Reports
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• v.28 no.4
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• pp.348-352
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• 1995

A thermophilic Bacillus sp. strain KK-1 isolated from soil produced an extracellular xylanase. From the culture supernatant of Bacillus sp., the xylanase was purified to homogeneity by ammonium sulfate precipitation and DEAE-Sephadex A-50 chromatography. The molecular weight of the purified xylanase was estimated to be 45 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel permeation chromatography. The apparent $K_m$ values for xylanase, using oat spelt xylan and birchwood xylan as substrates, were 7.1 mg/ml and 3.2 mg/ml, and $V_{max}$ values were $27.0\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$ and $29.0\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$, respectively. The xylanase hydrolyzed oat spelt xylan to mostly xylobiose, xylotriose, and xylose. The amino acid composition indicated that the xylanase contained high amounts of amino add residues of glutamic acid and glutamine (Glx) and aspartic acid and asparagine (Asx).

• KSBB Journal
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• v.26 no.5
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• pp.465-470
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• 2011

Twenty six microorganisms were isolated from soil and horse manure samples from in Iowa, U.S. Microorganisms were cultivated and screened by using plate count agar (PCA) at $35^{\circ}C$ containing 1% (w/v) oat spelt xylan instead of glucose. The xylanase activities of bacterial strains were analyzed by measuring the concentration of reducing sugar by DNS method. All isolated strains were characterized as the rod form and gram positive strains. Among the isolated strains, the HM6 strains gave the highest xylanase activity. This strain was identified as Bacillus pumilus HM6 by 16S rDNA sequence, morphological and biochemical analysis. Optimal culture temperature and initial medium pH for B. pumilus HM6 were $30-35^{\circ}C$ and pH 6-7, respectively. The maximum xylanase activity of 6879 IU/mL was obtained after growth of HM6 with 1% (w/v) oat spelt xylan at $35^{\circ}C$ for 6 days. Studies on enzymatic properties showed that the optimum conditions for the highest xylanase activity were $60^{\circ}C$ and pH 8.0. In addition, xylanase activity was stable over 2 hours at $50^{\circ}C$, whereas activity decreased after 30 min at $70^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.252-258
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• 2011

A bacterial strain capable of hydrolyzing xylan and locust bean gum (LBG) was isolated from farm soil by enrichment culture using mixture of palm kernel meal (PKM) and wheat bran as carbon source. Nucleotide sequence of 16S rDNA amplified from the isolate YB-1107 showed high similarity with those of genus Cellulosimicrobium strains. Xylanase productivity was increased when the Cellulosimicrobium sp. YB-1107 was grown in the presence of wheat bran or oat spelt xylan, while mannanase productivity was increased drastically when grown in the presence of PKM or LBG. Particularly, maximum mannanase and xylanase activities were obtained in the culture filtrate of media containing 0.7% PKM or 1% wheat bran, respectively. Both enzyme activities were produced at stationary growth phase. Mannanase from the culture filtrate showed the highest activity at $55^{\circ}C$ and pH 6.5. Xylanase activity was optimal at $65^{\circ}C$ and pH 5.5. The predominant products resulting from the mannanase or xylanase hydrolysis were oligosaccharides for LBG or xylan, respectively. In addition, the enzymes could hydrolyze wheat bran and rice bran into oligosaccharides.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.225-230
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• 2011

A bacterium producing the extracellular mannanase and xylanase was isolated from Korean farm soil by successive subcultures in a minimal medium supplemented with palm kernel meal (PKM) and rice bran. The isolate YB-1106 showed 98% similarity with Microbacterium arabinogalactanolyticum on the basis of 16S rRNA gene sequences. The additional carbohydrates including locust bean gum (LBG) and PKM increased the mannanase productivity of the YB-1106, while the xylanase productivity of the isolate was increased by wheat bran, oat spelt xylan, rice bran and xylose. Particularly, maximum mannanase and xylanase activities were obtained in the culture filtrate of tryptic soy broth supplemented with 1% LBG or 2% wheat bran, respectively. Both enzyme activities were produced at stationary growth phase. The mannanase of culture supernatant was the most active at $50^{\circ}C$ and pH 6.0, while xylanase of culture supernatant was the most active at $55^{\circ}C$ and pH 6.5. The predominant products resulting from the mannanase or xylanase hydrolysis were oligosaccharides for LBG or xylan, respectively.

• Journal of Microbiology and Biotechnology
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• v.7 no.2
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• pp.114-120
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• 1997

Microorganisms producing xylanase were screened for the enzymatic production of xylo-oligo saccharides from xylan. One of the bacteria isolated from compost produced an endoxylanase extracellularly. The bacterium was identified as Bacillus sp. according to its taxonomic characteristics examined. Xylanase production reached upto 5 U/ml after 22 h of culture in LB medium at $30^{\circ}C$. The xylanase was purified by ammonium sulfate precipitation and gel filtration. The molecular weight of the xylanase was estimated to be 20,400 by SDS-PAGE. Optimal temperature and pH for the xylanase activity was $60^{\circ}C$ and 6.5, respectively. The enzyme was stable at temperatures upto $40^{\circ}C$ and pH values from 4 to 10. The xylanase was completely inhibited by the addition of 2 mM mercury ion. Apparent $K_m$ and $V_max$ values for oat spelt xylan were 9.2 mg/ml and 1954 U/mg protein, respectively. For birchwood xylan, the values were 6.3 mg/ml and 1009 U/mg protein. The predominant products of the xylan hydrolysis were xylobiose, xylotriose and xylotetraose, indicating that the enzyme is an endoxylanase. Upto $85{\%}$ of the initially added enzyme (2 U/ml) was bound to 50 mg/ml of the insoluble fraction of oat spelt xylan after incubation at $30^{\circ}C$ for 30 min.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.4
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• pp.43-50
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• 2008

Adsorption of xylans extracted from birchwood and oat spelt on Hw-BKP were analyzed using HPLC. The effect of xylan adsorption on paper properties such as tensile, tear index and brightness was also investigated. The constituents of xylan was analyzed with HPLC after hydrolysis with dilute sulfuric acid. It was shown that xylose was the major constituent and small amounts of glucose and galactose were contained in the xylan samples. Adsorption of xylan on hardwood fibers was evaluated using acid hydrolysis and HPLC techniques. Results showed that the adsorption of negatively charged xylan on the fiber surface was negligible probably because electrostatic repulsion between these two materials. Pretreatment of the fiber with alum increased xylan adsorption. The amount of adsorption increased up to 30 mg/g. With the increase of xylan adsorption both tensile and tear strength of the handsheet increased suggesting xylan can be a very effective strength agents for papermaking. Brightness of the handsheets decreased, however, with the use of xylan.

• Korean Journal of Agricultural Science
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• v.39 no.2
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• pp.255-261
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• 2012

A bacterium AB-55, isolated from waste mushroom bed of Agaricus bisporus in Sukseong-myeon, Buyeo-gun, Chungcheongnam-do, Korea, was screened onto xylan agar congo-red plate by the xylanolysis method and was used to produce an xylanase in shaker buffle flask cultures containing oat spelt xylans. The phylogenetic analysis using 16S rRNA gene sequence data showed that the strain AB-55 had the highest homology (99.0%) with Bacillus subtilis and it was named as Bacillus subtilis AB-55. A xylanase was purified by ammonium sulfate precipitation (50~80%), gel filtration on sephacryl S-300, and ion exchange chromatography on DEAE sepharose FF. The molecular weight of the xylanase was estimated as 44 kDa by SDS-PAGE. Optimal pH and temperature for the xylanase activity was pH 7 and $50^{\circ}C$, respectively. N-terminal amino acid sequence of the enzyme was identified as Ser-Ala-Val-Lys-His-Gly-Ala-Ile-Val-Phe. The substrate specificity of the enzyme exhibited that it hydrolyzed efficiently oat spelt xylan as well as beechwood xylan, but showed no activity against Avicel and carboxymethyl clellulose (CMC). The enzyme activity was enhanced by $Fe^{2+}$ and $Mn^{2+}$ whereas was entirely inhibited by $Hg^+$.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.489-496
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• 2014

High levels of extracellular xylanase activity (211.79 IU/mg) produced by Paenibacillus sp. NF1 were detected when it was submerged-cultured. After three consecutive purification steps using Octyl-Sepharose, Sephadex G75, and Q-Sepharose columns, a thermostable xylanase (XynNF) was purified to homogeneity and showed a molecular mass of 37 kDa according to SDS-PAGE. The specific activity of the purified XynNF was up to 3,081.05 IU/mg with a 14.55-fold purification. The activity of XynNF was stimulated by $Ca^{2+}$, $Ba^{2+}$, DTT, and ${\beta}$-mercaptoethanol, but was inhibited by $Fe^{2+}$, $Zn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, SDS, and EDTA. The purified XynNF displayed a greater affinity for oat spelt xylan with the maximal enzymatic activity at $60^{\circ}C$ and pH 6.0. XynNF, which was shown to be cellulose-free, with high stability at high temperature ($70^{\circ}C-80^{\circ}C$) and low pH range (pH 4.0-7.0), is potentially valuable for various industrial applications. The enzyme hydrolyzed oat spelt xylan to yield mainly xylooligosaccharides (95.8%) of 2-4 degree of polymerization (DP2-4). Moreover, the majority of the xylooligosacharides (DP2-4) products was xylobiose (61.5%). The thermostable xylanase (XynNF) thus seems potentially usefull in the production of xylooligosaccharides.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.247-252
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• 2002

A bacterium producing the extracellular mannanase was isolated from Korean formented food and has been identified as a member of the genus Bacillus from the result of the phylogenic analysis based on partial 165 rRNA sequences. The isolate, named Bacillus sp. WL-3, was shown to be similar to B. subtilis strain on the basis of its biochemical properties. The mannanase of culture supematant was the most active at $55^{\circ}C$ and pH 6.0. The additional carbohydrates including u-cellulose, avicel, oat spelt xylan, guar gum and locust bean gum (LBG) increased the mannanase productivity. Especially, the maximum mannanase productivity was reached 65.5 U/ml in LB medium supplemented with 0.5% (w/v) LBG, which was 131-folds more than that in LB medium. It was sug-gested that the increase of mannanase production was owing to induction of mannanase biosynthesis by LBG hydrolysates transported following initial hydrolysis by extracellular mannanase during the cell growth. The molec-ular weight of WL-3 mannanase was estimated to approximately 38.0 kDa by zymogram on SDS-PAGE.