• 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 Animal Science and Technology
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• v.51 no.5
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• pp.427-432
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• 2009

This study was undertaken to screen a high xylanase and mannanase producing microbes. In the first experiment, screening was undertaken against 50 samples of microorganisms having xylanase and mannanase activities from soil and fallen leaves. The screening process has focused on picking out fungi having high xylanase and mannanase activities under the solid-state fermentation. The xylanase and mannanase activities of 6 screened microbes were 0.9~1.6 unit/mL and 0.2~0.4 unit/mL, respectively, under the submerged fermentation condition. However, under the solid-state fermentation, xylanase and mannanase activities were 103.7~220.0 unit/g and 20.1~40.3 unit/g, respectively. Finally one microbe (E-3) was selected and its xylanase and mannanase activities were 197.3 unit/g and 39.9 unit/g, respectively. The morphological and molecular biological classification of E-3 showed 99% homology with the Aspergillus niger.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.414-419
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• 1996

The xylnX gene encoding a xylanase from Clostridium thermocellum ATCC27405 was cloned in the plasmid pJH27, an E. coli-Bacillus shuttle vector and the resultant recombinant plasmid, pJX18 was transformed into E. coli HB101. The overexpressed xylanase was found to be secreted into the periplasmic space of the recombinant E. coli cells. The crude enzyme was obtained by treating the E. coli cells with lysozyme, and purified by DEAE-Sepharose column chromatography. Molecular wieght of the xylanase was estimated to be 53 kDa by gel filtration. The pI value was determined to be pH 8.8. The N-terminal sequence of the enzyme protein was Asp-Asp-Asn-Asn-Ala-Asn-Leu-Val-Ser-Asn which was considered to be the sequence of that of the mature form protein. The Km value of the enzyme for oat spelt xylan was calculated to be 2.63 mg/ml and the Vmax value was $0.47 {\mu}mole/min$. The xylanase had a pH optimum for its activity at pH 5.4 and a temperature optimum at $60^{\circ}C$. The enzyme hydrolyzed xylan into xylooligosaccharides which were composed mainly of xylobiose (40%) and xyloltriose (12%) after 5 hour reaction. This result indicates that the xylanase from C. thermocellum ATCC27405 is an endo-acting enzyme.

• The Korean Journal of Mycology
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• v.25 no.2 s.81
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• pp.91-100
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• 1997

Production of alkaline carboxymethyl cellulase (CMCase) and xylanase by batch and fed-batch cultures of alkalophilic Cephalosporium sp. RYM-202 was investigated. Of carbon sources tested, wheat bran gave the highest production of those enzymes. The high levels of CMCase on carboxymethyl cellulose and xylanase on birchwood xylan suggest that the biosynthesis of CMCase and xylanase in Cephalosporium sp. RYM-202 is regulated separately at the level of enzyme induction. The temperature and pH for maximal production of those enzymes was $20^{\circ}C$ and 9.0, respectively. High concentration of wheat bran in batch fermentation resulted in the lower and delayed production of the enzymes by catabolite repression. In fed-batch fermentation with controlled feeding of 5% final wheat bran concentration, the highest activities of CMCase and xylanase were 0.39 and 9.2 units/ml, respectively, and 1.22 and 1.36 times higher respectively than those in batch fermentation on 5% wheat bran.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.945-951
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• 2013

In vitro studies were undertaken to develop an appropriate fibrolytic enzymes cocktail comprising of cellulase, xylanase and ${\beta}$-D-glucanase for maize stover with an aim to increase its nutrient utilization in sheep. Cellulase and xylanase added individually to ground maize stover at an increasing dose rates (0, 100, 200, 400, 800, 1,600, 3,200, 6,400, 12,800, 25,600, 32,000, 38,400, and 44,800 IU/g DM), increased (p<0.01) the in vitro dry matter digestibility and in vitro sugar release. The doses selected for studying the combination effect of enzymes were 6,400 to 32,000 IU/g of cellulase and 12,800 to 44,800 IU/g of xylanase. At cellulase concentration of 6,400 IU/g, IVDMD % was higher (p<0.01) at higher xylanase doses (25,600 to 44,800 IU/g). While at cellulase doses (12,800 to 32,000 IU/g), IVDMD % was higher at lower xylanase doses (12,800 and 25,600 IU/g) compared to higher xylanase doses (32,000 to 44,800 IU/g). At cellulase concentration of the 6,400 to 32,000 IU/g, the amount of sugar released increased (p<0.01) with increasing levels of xylanase concentrations except for the concentration of 44,800 IU/g. No effect of ${\beta}$-D-glucanase (100 to 300 IU/g) was observed at lower cellulase-xylanase dose (cellulase-xylanase 12,800 to 12,800 IU/g). Based on the IVDMD, the enzyme combination cellulase-xylanase 12,800 to 12,800 IU/g was selected to study its effect on feed intake and rumen fermentation pattern, conducted on 12 rams (6 to 8 months; $20.34{\pm}2.369$ kg body weight) fed 50% maize stover based TMR. The total volatile fatty acids (p<0.01) and ammonia-N concentration was higher in enzyme supplemented group, while no effect was observed on dry matter intake, ruminal pH and total nitrogen concentration.

• 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.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.17 no.2
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• pp.88-93
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• 1989

To improve a new yeast strain capable of converting xylan to ethanol directly, we tried protoplast fusion between xylose fermenting yeast (Candida sp. X-6-41) and xylan assimilating yeast (Crypto-coccus sp. XB-33), finally selected the most promising two fusants (XFU-1 and XFU-2). As the optimum conditions for protoplast formation, the yeast cells were cultured to exponential phase in YPD and YPX containing 0.6M KCI, respectively, and then treated with zymolyase (0.25mg/$m\ell$), cellulase(4mg/$m\ell$) and 100mM 2-mercaptoethanol at pH 8 and 3$0^{\circ}C$. The protoplasts of parental auxotrophs were fused in the presence of 20mM CaCl$_2$and 40% polyethylene glycol(M.W.4000). The physiological and morphological characteristics of the fusants, such as assimilation of carbon sources, cell size, growth rate, xylanase activity and xylan fermentation ability were investigated. Xylanase activity of fusants that cultured in chemically minimal medium was higher than that of fusants that cultured in completed medium, because xylanase producing activity of xylose fermenting yeast(X-6-41) was inhibited by isoleucine.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.337-340
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• 2001

The production of xylanase from Aspergillus niger mutant in SSF was optimized by' using statistical experimental designs. An inoculum size of $5{\times}10^5$ spores/g. initial moisture content of 65 %. cultivation time of 5 days and 10 times concentration of basal medium containing 50 times concentration of CSL were optimum for xylanase production ‘ Under the optimized conditions. the activity and productivity of xytanase obtained after 5 days of fermentation were 5.071 IU/gram of rice straw and 14.790 IU/l.h. respectively.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.313-320
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• 2014

Black liquor (BL) is a by-product of rice straw pulping process. It is a low costs raw material for production value-adding proteins and enzymes, which has been paid more and more attention to reduce its environmental pollution. Mixed cultures of micelial fungi, Trichoderma reesei Northern Regional Research Laboratory (NRRL)11236, Trichoderma reesei NRRL 6165 and Aspergillus niger strains NRC 5A, NRC 7A, and NRC 9A were evaluated for their ability to produce xylanase using crude hemicellulose (CHC) prepared from BL and peat moss as an inert support under solid state fermentation (SSF). The most potent strains, A. niger NRC 9A (818.26 U/g CHC) and T. reesei NRRL 6165 ($100.9{\pm}57.14$ U/g CHC), were used in a mixed culture to enhance xylanase production by co-culturing under SSF. In the mixed culture, xylanase production ($1070.52{\pm}12.57$ U/g CHC) was nearly1.3 and 10.6-fold increases over the activities attained in their monocultures, A. niger NRC 9A and T. reesei NRRL 6165, respectively. Optimization of the culture parameters of the mixed culture SSF process, concentration of ammonium sulfate and corn steep liquor, CHC/peat moss ratio, inoculum size and ratios of the two strains, initial pH value, initial moisture content and incubation time, exhibited a significant increase ($2414.98{\pm}84.02$ U/g CHC) in xylanase production than before optimization.