• Title/Summary/Keyword: alkalophilic Cephalosporium sp.

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Mode of Action and Chemical Modification of an Alkaline Xylanase (CX-III) from Alkalophilic Cephalosporium sp. RYM-202 (호알카리성 Cephalosporium sp. RYM-202로부터 분리된 alkaline xylanase (CX-III)의 작용 양상 및 화학적 변환)

  • Kang, Myoung-Kyu;Maeng, Pil-Jae;Rhee, Young-Ha
    • The Korean Journal of Mycology
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    • v.24 no.4 s.79
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    • pp.255-264
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    • 1996
  • The hydrolysis products formed from birchwood xylan by the action of an alkaline xylanase (CX-III) from alkalophilic Cephaloxporium sp. RYM-202 were xylobiose and xylooligosaccharides polymerized with more than 4 sugar molecules. This enzyme was not active on xylobiose but readily attacked xylotriose accumulating xylobiose as a major product. The predominant end-products from xylotetraose by CX-III were xylobiose and xylotriose. These results indicate that the enzyme is typically endo-type xylanase possessing transglycosidase activity. Chemical modification of CX-III with N-bromosuccinimide revealed that two tryptophan residues per molecule of CX-III were essential for its catalytic activity on xylan. On the other hand, iodoacetamide and diethylpyrocarbonate did not influence the activity of the enzyme, suggesting that cysteine and histidine residues are not involved in the active site of this alkaline xylanase.

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Production of Alkaline Carboxymethyl Cellulase and Xylanase by Batch and Fed-batch Cultures of Alkalophilic Cephalosporium sp. RYM-202 (호알카리성 Cephalosporium sp. RYM-202의 회분 및 유가배양에 의한 Alkaline Carboxymethyl Cellulase와 Xylanase의 생산)

  • Kang, Myoung-Kyu;Kim, Do-Young;Rhee, Young-Ha
    • 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.

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Partial Purification and Some Properties of Carboxymethyl Cellulases from Alkalophilic Cephalosporium sp. RYM-202 (호알칼리성 Cephalosporium sp. RYM-202가 생산하는 carboxymethyl cellulase의 부분정제 및 특성)

  • Kang, Myoung-Kyu;Park, Hee-Moon;Rhee, Young-Ha;Kim, Yun-Seog;Kim, Yeo-Kyung
    • The Korean Journal of Mycology
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    • v.21 no.4
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    • pp.301-309
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    • 1993
  • An alkalophilic Cephalosporium sp. RYM-202 capable of producing cellulase components was isolated from soil. This organism grew best at an initial pH 9.0 and produced cellulase maximal at an initial pH 9.5-10.0. Three carboxymethyl cellulases(CMCases), P-I-I, P-I-II and P-II-I, were partially purified by DEAE-Sephadex A-50 ion exchange column followed by Sephadex G-150 gel filtration. The optimum pH values for activity were 7.5 for P-I-I, 8.0-9.5 for P-I-II and 7.5-10.0 for P-II-I. All CMCases were stable between pH 4.5 and 12.0. Temperature optima for activity ranged between 40 and $60^{\circ}C$ and more than 50% of the maximum activity was observed at $20^{\circ}C$ for both of P-I-I and P-II-I. The activity of CMCases was significantly stable in the presence of various laundry components, such as, surfactants, chelating agents and alkaline proteinases.

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Purification and characterization of a xylanase from alkalophilic cephalosporium sp. RYM-202

  • Kyu, Kang-Myoung;Kwon, Tae-Ik;Rhee, Yuung-Ha;Rhee, Young-Ha
    • Journal of Microbiology
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    • v.33 no.2
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    • pp.109-114
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    • 1995
  • Alkalophilic Cephalosporium sp. RYM-202 produced multiple xylanases extracellularly. One of these xylanases was purified to electrophoretical homogeneity by chromatography with DEAE-Sephadex A-50, Sephacryl S-200 HR and Superose 12 HR. The purified xylanase differed from most other microbial xylanases in that it had low-molecular weight and acidic isoelectric point. The molecular weight of the xylanase in that it had low-molecular weight and acidic isoelectric point. The molecular weight of the xylanase was 23 kDa by SDS-polyacrylamide electrophoresis and 24 kDa by gel permeation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity permentation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity permeation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity at pH 8.0 and 50 .deg.C. It was stable over a wide range of pH and retained more than 80% of its original activity after 24 h of incubation even at pH 12. The Km values of this enzyme on birchwood xylan and oat spelts xylan were 2.33 and 3.45 mg/ml, respectively. The complete inhibition of the enzyme of n-bromosuccinimide suggests the involvement of tryptophan in the active site. The sylanase lacked activity towards crystalline cellulose and carboxymethyl cellulose.

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Application of Alkaline Xylanase of Cephalosporium sp. RYM-202 in Enzymatic Treatment of Kraft Pulps (Cephalosporium sp. RYM-202가 생산하는 알카리내성 xylanase를 이용한 크라프트 펄프의 효소적 처리)

  • Kang, Myung-Kyu;Lee, Young-Ha;Kim, Byung-Hyun;Jeon, Yang
    • Korean Journal of Environmental Biology
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    • v.17 no.2
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    • pp.191-198
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    • 1999
  • Enzyme-aided bleaching of softwood and hardwood kraft pulps by a xylanase preparation from an alkalophilic fungus Cephalospotium sp. RYM-202 was studied. Maximal solubilization of Pulp xylan was obtained at 5$0^{\circ}C$ in both kraft pulps. The optimum pH of the enzyme for the hydrolysis of pulp xylan was 8.0 and more than 90% of the maximal activity was detected at 9.0. The positive effects of xylanase pretreatment on bleachability of softwood and hardwood kraft pulps were observed. The kappa number of softwood and hardwood kraft pulps was decreased by 3.7 and 2.0 units, respectively. The pulp fibre integrity was not significantly affected by xylanase pretreatment when the physical properties of handsheets made from xylanase-treated pulps were compared with those of handsheets from untreated pulps. These results indicate that the alkaline xylanase of Cephalospotium sp. RYM-202 is well suitable for application in enzymatic prebleaching of softwood and hardwood kraft pulps under the alkaline conditions.

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