• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1014-1021
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• 2004

Two thermostable xylanases, designated XynA and XynB, were purified to homogeneity from the culture supernatant of Paenibacillus sp. DG-22 by ion-exchange and gel-filtration chromatography. The molecular masses of xylanases A and B were 20 and 30 kDa, respectively, as determined by SDS-PAGE, and their isoelectric points were 9.1 and 8.9, respectively. Both enzymes had similar pH and temperature optima (pH 5.0-6.5 and $70^{\circ}C$), but their stability at various temperatures differed. Xylanase B was comparatively more stable than xylanase A at higher temperatures. Xylanases A and B differed in their $K_m$ and $V_{max}$ values. XynA had a $K_m$ of 2.0 mg/ml and a $V_{max}$ of 2,553 U/mg, whereas XynB had a K_m$ of 1.2 mg/ml and a $V_{max}$, of 754 U/mg. Both enzymes were endo-acting, as revealed by their hydrolysis product profiles on birchwood xylan, but showed different modes of action. Xylotriose was the major product of XynA activity, whereas XynB produced mainly xylobiose. These enzymes utilized small oligosaccharides such as xylotriose and xylotetraose as substrates, but did not hydrolyzed xylobiose. The amino terminal sequences of XynA and XynB were determined. Xylanase A showed high similarity with low molecular mass xylanases of family 11.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.592-597
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• 1991

An extracellular xylanase of Bacillus stearothemophilus was purified to a single protein through a sequency of operations including ammonium sulfate fractionation, DEAE Sepharose CL-6B ion exchange chromatography, Sephadex G-100 gel filtration and heat treatment. The purified enzyme had a moleular weight of 170, 000. the pH and temperature optima for the enzyme activity were pH 9.0 and $55^{\circ}C$, respectively. The activity was enhanced by $co^{2+} \; and\; Mn^{2+}$, and inhibited by $Hg^{2+}$. Pattern of hydrolysis demonstrated that the xylanase was an endo-splitting enzyme able to break down larchwood xylan at random giving xylobiose and xylotriose as the main end products.

• Journal of Korea Society of Waste Management
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• v.34 no.5
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• pp.474-481
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• 2017

This study was conducted to investigate the effects of inoculum and carbon sources on anaerobic digestion characteristics. The treatments were combinations of inoculum (digestate of cattle manure and rumen fluid) with carbon sources (starch, cellulose, and xylan). Anaerobic digestion was performed in triplicate at $37^{\circ}C$ for 18 days at 100 rpm. Sampling was performed at 0, 1, 2, 3, 4, 5, 7, 9, 12, 15, and 18 days to measure pH, ammonia-N, volatile solids reduction, the cumulative methane content, and the cumulative methane production. There was a significant difference in methane content depending on the carbon source and there was a significant difference in pH, ammonia-N, methane production, and methane content depending on the inoculum (P < 0.05). The results of methane production were higher in the digestate of cattle manure treatment than in the rumen fluid treatment (P < 0.05). In this study, different digestive patterns depending on the type of carbon source could be used as basic research data to set the hydraulic residence time of anaerobic digestion facilities. In addition, the use of ruminal fluid as an inoculum may help accelerate the hydrolysis and acid production steps.

• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.18-25
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• 1987

The cellulolytic activities of Aspergillus fumigatus KC-1 was investigated, which showed the most active producer of cellulase among the 256 strains of cellulose-decomposing microorganisms screened in our laboratory. All the examined cellulolytic activities (filter paper-, Avicel-, cotton-, CMC-, salicin- and xylansaccharifying activity) in a culture of A. fumigatus KC-1 grown on 1% popular sawdust pretreated with peroxide alkaline reached a maximum within 4-5 days. The optimum pH and temperature for the enzymatic activity was found to be pH 4.5 and $60^{\circ}C$ respectively. The sawdust of poplar wood delignified with 1% NaOH and 20% peracetic acid succesively recorded the highest hydrolysis rate in the tests of enzymatic saccharification. The major end product of hydrolysis of poplar wood with the cellulolytic enzymes obtained from A. fumigatus KC-1 was glucose with small amount of cellobiose and xylose. It can be concluded from these results that A. fumigatus KC-1 is an advantagous source of a cellulase that is capable of hydrolyzing cellulose to glucose rapidly. The influence of degree of delignification, substrate size and its concentration on the rate of hydrolysis of poplar wood was also discussed.

• KSBB Journal
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• v.29 no.5
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• pp.316-322
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• 2014

Xylanase have been used to convert the polymetric xylan into fermentable sugars from the production of ethanol and xylitol from plant biomass. The aim of this study was to isolate and identify xylanolytic bacterium from herbivore feces and was to used the xylanase for enzymatic hydrolysis of biomass. Xylanolytic strains were isolated from 59 different feces of herbivores from Seoul Grand Park located in Gwacheon Gyeonggi-do. The xylanolytic strains were selected by congo red staining and DNS method. Total 67 strains isolated from the herbivores feces were tested for xylanase activity. Among the strains, H10-1, which has the highest xylanase activity, was isolated from feces of Ceratotherium simum. The H10-1 strain was identified as Bacillus pumilus based on its morphological/biochemical characteristics and partial 16S rDNA gene sequences. Culture conditions of B. pumilus H10-1 such as initial medium pH, incubation temperature and incubation time were optimized for maximum xylanase production. And also xylanase produced by B. pumilus H10-1 was applied for the saccharification of Miscanthus sacchariflorus cv. 'Geodae 1', which was pretreated with 1.5M NaOH. The optimized culture conditions of B. pumilus H10-1 were pH 9, $30^{\circ}C$ incubation temperature, and 7 day incubation time, respectively. This xylanase activity under the optimized conditions was $20.4{\pm}3.3IU$. The crude xylanase produced by B. pumilus H10-1 was used for the saccharification of xylan derived from pretreated 'Geodae 1'. The saccharification conditions were $50^{\circ}C$, 200 rpm, and 5 days. Saccharification efficiency of pretreated 'Geodae 1' by B. pumilus H10-1 was 8.2%.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.263-271
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• 2013

A xylanase-producing bacterium was isolated from a soil sample collected in Yongin city, Korea. The strain was aerobic and gram positive, and grew between pH 5.0 and 11.0, forming a yellow-colored colony. The strain was classified as a novel subspecies bacterium of Paenibacillus barcinonensis by 16S rRNA gene sequence similarity, phylogenetic analysis, phenotypic, and biochemical characteristics, and thus named Paenibacillus sp. HX-1. This strain produced extracellular endo-${\beta}$-1,4-xylanase, and the best xylanolytic activity (205.17 unit/ml) was obtained at 96 h in an optimized TNX medium containing 1% (w/v) bacto tryptone, 1% (w/v) NaCl, and 0.7% (w/v) beechwood xylan at pH 7.0, $37^{\circ}C$ and 200 rpm. The endo-${\beta}$-1,4-xylanase produced by the strain HX-1 yielded xylobiose as the end product from beechwood xylan hydrolysis. The enzyme exhibited optimum pH and temperature at pH 7.0 and $45^{\circ}C$, respectively. The remarkable enhancing effect of the TNX medium on xylanase production by HX-1, in spite of its simple formula, may have great advantages for industrial applications of xylanase.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.794-801
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• 2013

This paper reports the production and characterization of crude xylanase from the newly isolated Humicola sp. Ly01. The highest (41.8 U/ml) production of the crude xylanase was obtained under the optimized conditions (w/v): 0.5% wheat bran, 0.2% $KH_2PO_4$, and 0.5% peptone; initial pH 7.0; incubation time 72 h; $30^{\circ}C$; and 150 rpm. A considerable amount of the crude xylanase was induced using hulless barley bran or soybean meal as the carbon source, but a small amount of the enzyme was produced when supplementary urea was used as the nitrogen source to wheat bran. The crude xylanase showed apparent optimal cellulase-free xylanase activity at $60^{\circ}C$ and pH 6.0, more than 71.8% of the maximum xylanase activity in 3.0-30.0% (v/v) ethanol and more than 82.3% of the initial xylanase activity after incubation in 3.0-30.0% (v/v) ethanol at $30^{\circ}C$ for 2 h. The crude xylanase was moderately resistant to both acid and neutral protease digestion, and released 7.9 and 10.9 ${\mu}mol/ml$ reducing sugar from xylan in the simulated gastric and intestinal fluids, respectively. The xylooligosaccharides were the main products of the hydrolysis of xylan by the crude xylanase. These properties suggested the potential of the crude enzyme for being applied in the animal feed industry, xylooligosaccharides production, and high-alcohol conditions such as ethanol production and brewing.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1555-1565
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• 2009

Anaerobic rumen fungi have been regarded as good genetic resources for enzyme production which might be useful for feed supplements, bio-energy production, bio-remediation and other industrial purposes. In this study, an expressed sequence tag (EST) library of the rumen anaerobic fungus Neocallimastix frontalis was constructed and functional genes from the EST library were analyzed to elucidate carbohydrate metabolism of anaerobic fungi. From 10,080 acquired clones, 9,569 clones with average size of 628 bp were selected for analysis. After the assembling process, 1,410 contigs were assembled and 1,369 sequences remained as singletons. 1,192 sequences were matched with proteins in the public data base with known function and 693 of them were matched with proteins isolated from fungi. One hundred and fifty four sequences were classified as genes related with biological process and 328 sequences were classified as genes related with cellular components. Most of the enzymes in the pathway of glucose metabolism were successfully isolated via construction of 10,080 ESTs. Four kinds of hemi-cellulase were isolated such as mannanase, xylose isomerase, xylan esterase, and xylanase. Five $\beta$-glucosidases with at least three different conserved domain structures were isolated. Ten cellulases with at least five different conserved domain structures were isolated. This is the first solid data supporting the expression of a multiple enzyme system in the fungus N. frontalis for polysaccharide hydrolysis.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.613-618
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• 2006

Two endoxylanases from an alkaliphilic bacterium, Bacillus halodurans C-1, were purified 3.8- and 7.9- fold with specific activities of 9.4 and 19.8U/mg protein, respectively. The molecular masses of both purified enzymes were 23 and 47 kDa, respectively, and 23 kDa xylanase I (Xyl I) exhibited an optimum pH at 7.0, whereas 47 kDa xylanase II (Xyl II) showed a broad pH range of 5.0 to 9.0. The temperature optima of both xylanases were $60^{\circ}C\;and\;70^{\circ}C$, respectively. Both were stable in the pH range of 6.0 to 9.0 and 5.0 to 10.0, respectively, and they were stable up to $60^{\circ}C\;and\;70^{\circ}C$, respectively. The $K_m\;and\;V_{max}$ of Xyl I were 4.33mg/ml and $63.5{\mu}mol/min/mg$, respectively, whereas Xyl II had a $K_m$ value of 0.30 mg/ml and $V_{max}$ of $210{\mu}mol/min/mg$. Both xylanases hydrolyzed xylans from birchwood, oat spelt, and larchwood. However, they showed different modes of action; a series of xylooligosaccharides larger than xylotriose were released as the major products by Xyl I, whereas xylobiose and xylotriose were the main products by Xyl II. The maximum synergistic action of the two enzymes on hydrolysis of xylan was 2.16 with the ratio of Xyl I to Xyl II at 1:9.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.271-276
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• 2017

A highly thermostable ${\beta}-(1-4)-glucanase$ (NA23_08975) gene (fig) from Fervidobacterium islandicum AW-1, a native-feather degrading thermophilic eubacterium, was cloned and expressed in Escherichia coli. The recombinant FiG (rFiG) protein showed strong activity toward ${\beta}-{\small{D}}-glucan$ from barley (367.0 IU/mg), galactomannan (174.0 IU/mg), and 4-nitrophenyl-cellobioside (66.1 IU/mg), but relatively weak activity was observed with hydroxyethyl cellulose (5.3 IU/mg), carboxymethyl cellulose (2.4 IU/mg), and xylan from oat spelt (1.4 IU/mg). rFiG exhibited optimal activity at $90^{\circ}C$ and pH 5.0. In addition, this enzyme was extremely thermostable, showing a half-life of 113 h at $85^{\circ}C$. These results indicate that rFiG could be used for hydrolysis of cellulosic and hemicellulosic biomass substrates for biofuel production.