• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1856-1861
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• 2006

A Bacillus sp. A-6 strain that produced xylanase was isolated from rice bran. The optimal temperature and pH for xylanase activity of the culture supernatant of Bacillus sp. A-6 were 40$^{\circ}C$ and pH 7, respectively. The optimal temperature and pH for xylanase production in the xylan medium were 30$^{\circ}C$ and pH 9, respectively. The optimal concentrations of oat spelt xylan and peptone for xylanase production were 0.5% and 1.5%, respectively. The best nitrogen sources for xylanase production was beef extract, but xylanase production was also supported comparably by tryptone and peptone. The bacterial growth in the optimal xylan medium reached stationary growth phase after 12 h of incubation. The xylanase production in the culture supernatant increased dramatically during the initial 12 h exponential growth phase and then remained constant at 23.8-24.5 unit/ml during the stationary growth phase. The pH of the culture medium decreased from 8.8 to 6.7 during the exponential growth phase and subsequently increased to 8.1 during the stationary growth phase. Rice bran, sorghum bran, and wheat bran as well as oat spelt xylan induced xylanase production. The xylanase production was repressed when glucose was added to the xylan-containing medium.

• 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.13 no.5
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• pp.618-625
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• 2003

Investigations were carried out to optimize the culture conditions for the production of xylanase by Paenibacillus sp. DG-22, a moderately thermophilic bacterium isolated from timber yard soil. Xylanase production showed a cell growth associated profile. Xylanase activity was found only in the culture supernatant, while $\beta-xylosidase$ activity was mainly associated with the cells. The formation of xylanase activity was induced by xylan and repressed by glucose and xylose. The production profile of xylanase was examined with various commercial xylan and maximum yield was achieved with 0.1∼ 0.5% birchwood xylan. Among various nitrogen sources tested, yeast extract was optimal for the production of xylanase. The xylanase activity was inhibited by $Co^{2+},\; Cu^{2+},\; Fe^{3+},\; Hg^{2+}\;$ and$\;Mn^{2+}$ ions while $Ca^{2+},\; Mg^{2+},\; Ni^{2+},\; Zn^{2+}$ions and DTT stimulated xylanase activity Mercury (II) ion at 5 mM concentration abolished all the xylanase activity. The predominant products of xylan-hydrolysate were xylobiose, xylotriose, and higher xylooligo-saccharides, indicating that the enzyme was an endoxylanase.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.157-162
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• 1999

Bacillus pumilus PJ19 isolated from Pinus leaves showed optimum xylanase production when grown in yeast tryptone broth at $37^{\circ}C$, pH 7.2, and shaken at 200 rpm after 48 h of incubation. Xylanase production was induced by xylan and xylose but repressed in the presence of glucose. Xylanase production by B. pumilus PJ19 was not growth-associated and the maximum enzyme production was found after 36 h of incubation.

• 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.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.85-87
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• 1989

Cultural conditions for the formation of extracellular xylanase by Candida sp. X-6-41 were investigated. The xylanase was not produced in culture medium containing polypeptone or yeast extract as a nitrogen source, respectively, whereas the enzyme w8s produced in chemically defined medium containing (NH$_4$)$_2$SO$_4$as a sole nitrogen source. The xylanase production was affected by the amino acids such as isoleucine and tryptophan. The enzyme production of the strain was completely inhibited by the addition of isoleucine in the culture medium, but enhanced by tryptophan below the concentration of 25$\mu$g/$m\ell$.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.543-550
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• 1992

The production of xylanase and $\beta$-xylosidase was investigated in submerged culture of Aspergillus niger NRC 107. The maximum production occurred when the pH was controlled at 6.0 during the fermentation. Among the various carbon sources investigated, corn-cob xylan (1.5%, w/v) yielded maximal production of the enzymes. The $NaNO_{3}$ was the most favorable nitrogen source for enzyme production and $KH_2P0_4$ concentration at 0.3%(w/v) was found to be optimum. Incorporation of wheat bran to the culture medium improved xylanase production. Addition of L( -) sorbose to the culture medium promoted the secretion of $\beta$-xylosidase. It was possible to increase the production of xylanase (39.43 units/ml) and that of $\beta$-xylosidase (4.2 unitslml) by submerged culturing the A. niger NRC 107 in the modified medium.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.370-377
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• 1999

Thermo-tolerant bacterium producing the xylanase was isolated from soil and identified as Bacillus pumilus. This strain, named Bacillus pumilus TX703, was able to grow ad produce xylanase at the culture temperature of 5$0^{\circ}C$. The maximum xylanase production was obtained when 1%(w/v) birchwood xylan and 1% (w/v) soytone were used as carbon source and nitrogen source, respectively. The biosynthesis of xylanase was under the catabolite repression induced by glucose in the culture medium, and it was completely inhibited in the presence of 0.2% (w/v) glucose. The maximum activity of xylanase was observed from pH8.0 to 9.0 and from 50 to 6$0^{\circ}C$ and the enzyme was highly heat-stable, whose activity remained was over 50% at 8$0^{\circ}C$, and was quite stable from pH5.0 to 10.0.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.123-128
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• 2002

A bacterium producing the extracellular xylanase was isolated from soil and has been identified as a Bacillus sp. strain. The isolate, named Bacillus sp. AMX-4, was shown to be similar to B. subtilis strain on the basis of its chemical compositions. The xylanase of culture supernatant was most active at 50℃ and pH 6.0. The additional carbon sources including monosaccharides, disaccharides, wheat bran, and rice straw increased the enzyme productivity. Especially, the maximum xylanase productivity was reached 29.2 units/ml in LB medium supplemented with 1.5％ (w/v) xylose, which was 16-folds more than that in LB medium. As the results of investigating the effects of xylose on cell growth and xylanase productivity of Bacillus sp. AMX-4, increase of xylanase production was owing to the induction of xylanase biosynthesis. It was also found that the enzyme production was in association with the growth of Bacillus sp. AMX-4.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.157-164
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• 2003

An alkali-tolerant bacterium producing the xylanase was isolated from soil and identified as Bacillus alcaiophilus. This strain, named B. alcalophilus AX2000, was able to grow and produce xylanase optimally at pH 10.5 and $37^{\circ}C$. The maximum xylanase production was obtained when 0.5%(w/v) birchwood xylan and 0.5%(w/v) polypeptone and yeast extract were used as carbon source and nitrogen source, respectively. The biosynthesis of xylanase was under the catabolite repression by glucose in the culture medium, and inhibited in the presence of high concentration of xylose. The maximum activity of xylanase was observed at pH 10.0 and $50^{\circ}C$ and the enzyme activity remained was over 80% at $60^{\circ}C$ and from pH 5.0 to 11.0.