• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.59-68
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• 2023

Xylanase is an industrially relevant enzyme used for the production of xylobiose and xylose. Various methods are used to enhance the microbial yield of xylanase. In the present study, co-culturing of Bacillus subtilis and Bacillus pumilus were investigated using submerged fermentation for xylanase production, which was markedly increased when sal, sagwan, newspaper, wheat bran, and xylan were used as single carbon sources. Maximum xylanase production was reported after 5 days of incubation in optimized media at pH 7.0 and 37℃, resulting in 2.69 ± 0.25 µmol/min by coculture. The 1:1 ratio of sal and sagwan in optimized production media was shown to be suitable for xylanase synthesis in submerged fermentation (SMF). In comparison to mono-culture using B. pumilus and B. subtilis, co-culturing resulted in an overall 3.8-fold and 2.15-fold increase in xylanase production, respectively.

• Journal of Life Science
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• v.12 no.2
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• pp.188-199
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• 2002

A gene coding for xylanase from thermo-tolerant Bacillus pumilus TX703 was cloned into Escherichia coli DH5 $\alpha$ using pUC19. Among 7,400 transformants, four transformants showed clear zones on the detection agar plates containing oat-spells xylan. One of them which showed highest xylanase activity was selected and its recombinant plasmid, named pXES106, was found to carry 2.24 kb insert DNA fragment. When the nucleotide sequence of the cloned xylanase gene (xynK) was determined, xynK gene was found to consist of 1,227 base-pair open reading frame coding for a polypeptide of 409 amino acids with a deduced molecular weight of 48 kDa. The coding sequence was preceded by a putative ribosome binding site, the transcription initiation signals, and cia-acting catabolite responsive element. The deduced amino acids sequence of xylanase is similar to those of the xylanases from Hordeum vulgare (barley) and Clostridium thermocellum, with 39 and 31% identical residues, respectively. The amino acids sequence of this xylanase was quite different from those of the xylanases from other Bacillus species.

• 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.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.271-279
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• 1992

Genomic DNA of Bacillus stearothemzophilus, which expressed alkalophilic and thermophilic xylanases, was partially digested with HindIII, cloned into pBR322, and subsequently transferred into the Escherichra coli HB101 cells. Three among 5, 000 transformants screened formed clear zones around their colonies. From the functional clones, three recombinant plasmids (pMG11, pMG12 and pMG13) had been isolated, and they were identified to carry the same 4 kb HindIII fragment originated from B. stearothemzophilus which was responsible for the xylanase activity. pMGl3, however, had the foreign DNA of opposite orientation compared to the other two recombinant plasmids. This recombinant plasmid gave much lower xylanase activity. B. stearothermophilus was observed to produce at least three xylanase activities as evidenced by the PAGE-xylan zymogram. The xylanase from E. coli HB101/pMG12 was judged to correspond to the largest among the three B. stearothermophilus xylanases observed in the zymogrom. The enzyme hydrolyzed xylooligosaccharides larger than xylotriose and degraded xylan to produce xylobiose and xylotriose as major products. The xylanase was considered to have trans-xylosidase activity, too.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.157-165
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• 1993

A 1, 4-.betha.-D-xylanase, designated as xylanase II, was purified from the culture filtrate of Trichoderma koningii ATCC 251131 by column chromatography on Sephadex G-75, SP-Sephadex C-50, DEAE-Sephadex A-50 and Sephadex G-50 with an overall yield of 6.97%. It has a molecular weight of 21.000 and an isoelectric point of 9.4. The enzyme activity is optimal at pH 5.0 and at a temperature of 50.deg.C. Xylanase II is stable up to 50.deg.C, while 40 and 90% of its activity are lost after the incubation for 30 and 60 min at 60.deg.C. The enzyme degrades xylan with relatively high activity, as well as carboxymethylcellulose and Avicel. Its $K_{m}$ values for oat-spelt xylan, larchwood xylan and Avicel are 7.48, 1.98 and 13.33 mg/ml, respectively. The hydrolysis products of oat-spelt xylan by xylanase II are xylose, xylobiose, xylotriose and arabinoxylotriose, while the reaction products of larchwood xylan are xylose, xylobiose, xylotriose and small amount of higher oligomers. The action paterns of the enzyme demonstrate that xylanase II is endo-enzyme.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.559-564
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• 1992

To increase the efficency of utilizing cellulosic biomass, a potent xylanase producing bacteria was isolated and identified as Bacillus sp. N-25. Extracellular xylanase from Bacillus sp. N-25 was partially purified by ammonium sulfate precipitation, DEAE-Sephadex A-25 and Sephadex G-IOO column chromatographies. The xylanase was single fraction on chromatography and was true xylanase without cellulase activity. The enzyme was stable at pH 6-8 and 80% activity was remained at $50^{\circ}C$ for 30 min, but was inhibited by $Hg^{2+}$, $Ag^{2+}$, and $Mn^{2+}$. From the fact that the major end product was xylose, we suggested that the enzyme is an exo-xylanase which may be a prime candidate for industrial use.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.304-310
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• 1995

A thermophilic bacterium producing the extracellular cellulase-free xylanase was isolated from soil and has been identified as Bacillus sp. The optimal growth temperature was 50$\circ$C and the optimal pH, 7.0. Under the optimal growth condition, maximal xylanase production was 2.2 units/ml in the flask culture. The enzyme production was induced by xylan and xylose, but was repressed by sucrose or trehalose. The partially purified xylanase was most active at 70$\circ$C. It was found that the enzyme was stable at 65$\circ$C for 10 hours with over 75% of the activity. The enzyme was most active at pH 7.0 and retained 90% of its maximum activity between pH 5.0 and pH 9.0 though Bacillus sp. was not grown on alkaline conditions (>pH 8.0). In addition, the activity of xylanase was over 60% at pH 10.0. At the ambient temperature, the enzyme was stable over a pH range of 5.0 to 9.0 for 10 h, indicating that the enzyme is thermostable and alkalotolerant. The activity of xylanase was completely inhibited by metal ions including Hg$^{2+}$ and Fe$^{2+}$, while EDTA, phenylmethylsulfonyl fluoride (PMSF), $\beta$-mercaptoethanol and SDS didn't affect its activity. The enzyme was also identified to exert no activity on carboxymethylcellulose, laminarin, galactomannan, and soluble starch.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.59-67
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• 2018

This study was conducted to isolate the cellulolytic bacteria able to grow on LB- Carboxymethyl cellulose (CMC) agar trypan blue medium from the mixed forest and Larix leptolepis stands. Three bacterial strains with high activity against both CMC and xylan were isolated. Both API kit test and 16S rRNA gene sequence analysis revealed that the three different isolates belong to the gene Bacillus. Therefore, the isolates named as Bacillus sp. EFL1, Bacillus sp. EFL2, and Bacillus sp. EFP3. The optimum growth temperature of Bacillus sp. EFL1, EFL2, and EFP3 were $37^{\circ}C$. The optimum temperature for CMCase and xylanase from Bacillus sp. EFL1 were $50^{\circ}C$. The optimum pH of Bacillus sp. EFL1 xylanase was pH 5.0 but the optimum pH of CMCase from Bacillus sp. EFL1 was pH 6.0. The optimum temperature of CMCase and xylanase from Bacillus sp. EFL2 was $60^{\circ}C$, respectively. The optimum pH of CMCase of Bacillus sp. EFL2 was 5.0, whereas xylanase showed high activity at pH 3.0-9.0. The optimum temperature for CMCase and xylanase of Bacillus sp. EFP3 was $50^{\circ}C$. The optimum pH for CMCase and xylanse was 5.0 and 4.0, respectively. CMCases from Bacillus sp. EFL1, EFL2, and EFP3 were thermally unstable. Although xylanase from Bacillus sp. EFL1 and EFP3 showed to be thermally unstable, xylanase from Bacillus sp. EFL2 showed to be thermally stable. Therefore, Bacillus sp. EFL2 has great potential for animal feed, biofuels, and food industry applications.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.527-533
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• 1992

The optimal conditions for cellulase and xylanase production by Trichoderma reesei 28217 were studied for enzymatic deinking of old newspaper. The amounts of cellulase and xylanase from the strain was varied by initial medium pH, Tween 80, inoculum size of spore suspension, and carbon and nitrogen sources. The optimal conditions for cellulase production were pH 5.0-6.5, 0.02% of Tween 80, 0.5-1.0% of inoculum size of spore suspension ($1{\times}10^{7}$/ml). cottonseed meal as nitrogen source, and corn flour as carbon source. On the other hand, the optimal conditions for xylanase production were pH 6.5, 0.01% of Tween 80, corn steep liquor as nitrogen source, and disintegrated old newspaper as carbon source. The inoculum size for xylanase production was the same as for cellulase production. The concomitant production of cellulase and xylanase in shake flask culture was efficiently induced in the medium containing 0.5% cottonseed meal as nitrogen source and 1.0% old newspaper and 2.0% corn flour as carbon sources. In this case the activities of cellulase and xylanase produced were 6.11-7.22 IU/mJ and 97.7 IU/ml. respectively. However, the cellulase production in $5{\ell}$ fermentor scale was slightly decreased compared with that in flask scale. Moreover, xylanase production was severely reduced in a fermentor scale. The study for the reason of decreased enzyme production in fermentor is further needed.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.9
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• pp.1288-1295
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• 2009

The study was conducted to investigate the effects of different levels of xylanase on performance, blood parameters, intestinal morphology, microflora and digestive enzyme activities of broilers. The wheat-based diets were supplemented with 0, 500, 1,000, 5,000 U/kg xylanase. Xylanase supplementation significantly (p<0.05) improved the feed:gain ratio of broilers from 1 to 21 d and 1 to 42 d. Supplementing 500 U/kg and 1,000 U/kg xylanase improved (p<0.05) the villus height and the ratio of villus height to crypt depth in the small intestine. Excess supplementation of xylanase (5,000 U/kg) increased the villus height in the ileum (p<0.01) and the ratio of villus height to crypt depth in the duodenum and ileum (p<0.05). The microflora in the ileum and caecum, digestive enzyme activities in the small intestine and the concentrations of serum glucose, uric acid, insulin and IGF-I were not affected by the supplementation of xylanase. Excess level of xylanase (5,000 U/kg) had a tendency to induce the multiplication of E. coli and total aerobes. The results suggested that supplementing 500 U/kg and 1,000 U/kg xylanase was beneficial for broilers and excess xylanase supplementation resulted in no further improvement or negative effects.