• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.800-805
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• 2007

Two endoglucanases with processive cellulase activities, produced from Fomitopsis palustris grown on 2% microcrystalline cellulose(Avicel), were purified to homogeneity by anion-exchange and gel filtration column chromatography systems. SDS-PAGE analysis indicated that the molecular masses of the purified enzymes were 47 kDa and 35 kDa, respectively. The amino acid sequence analysis of the 47-kDa protein(EG47) showed a sequence similarity with fungal glycoside hydrolase family 5 endoglucanase from the white-rot fungus Phanerochaete chrysosporium. N-terminal and internal amino acid sequences of the 35-kDa protein(EG35), however, had no homology with any other glycosylhydrolases, although the enzyme had high specific activity against carboxymethyl cellulose, which is a typical substrate for endoglucanases. The initial rate of Avicel hydrolysis by EG35 was relatively fast for 48 h, and the amount of soluble reducing sugar released after 96 h was $100{\mu}g/ml$. Although EG47 also hydrolyzed Avicel, the hydrolysis rate was lower than that of EG35. Thin layer chromatography analysis of the hydrolysis products released from Avicel indicated that the main product was cellobiose, suggesting that the brown-rot fungus possesses processive EGs capable of degrading crystalline cellulose.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.248-255
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• 2022

Phlebia sp. MG-60 is the salt-tolerant, white-rot fungus which was isolated from a mangrove forest. This fungus expresses three kinds of manganese peroxidase (MGMnP) isozymes, MGMnP1, MGMnP2 and MGMnP3 in low nitrogen medium (LNM) or LNM containing NaCl. To date, there have been no reports on the biochemical salt-tolerance of these MnP isozymes due to the difficulty of purification. In present study, we established forced expression transformants of these three types of MnP isozymes. In addition, the fact that this fungus hardly produces native MnP in a high-nitrogen medium (HNM) was used to perform isozyme-selective expression and simple purification in HNM. The resulting MGMnPs showed high tolerance for NaCl compared with the MnP of Phanerochaete chrysosporium. It was worth noting that high concentration of NaCl (over 200 mM to 1200 mM) can enhance the activity of MGMnP1. Additionally, MGMnP1 showed relatively high thermo tolerance compared with other isozymes. MGMnPs may have evolved to adapt to chloride-rich environments, mangrove forest.

• 임산에너지
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• 제20권1호
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• pp.6-11
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• 2001

한지의 원료가 되는 닥섬유의 펄프화를 위해 인피부에 목질 분해균을 처리하여 인피섬유의 단섬유화를 위한 미생물의 분해특성과 처리시간별 인피섬유의 분리에 대하여 검토하였다. 판막버섯이나 구름버섯으로 20일간 처리시 중량감소율이 약 50%에 이르러 오히려 이용 가능한 섬유소의 분해도 함께 초래하는 것으로 추정할 수 있다. 그러나 꽃구름버섯이나 벽돌빛뿌리 버섯은 인피섬유의 제일 외피에 존재하는 흑청색 부분을 잘 본해시키고 섬유소 손상을 적게하는 특성을 가진 것으로 나타났다. 꽃구름버섯은 처리 10일째가지 78.9%의 셀룰로오스 함량을 유지하고, 리그닌은 7.2%를 나타내어 제일 양호한 분해 양상을 보였다. 현미경적 관찰의 결과에서는 느타리버섯의 경우 처리 30일부터 인피부의 섬유가 분리되어 단섬유화 되며, 50일간 장기간 처리하여도 섬유표면의 손상은 발견되지 않았다.

• Journal of Microbiology
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• 제43권6호
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• pp.475-486
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• 2005

Fungal secondary metabolites constitute a wide variety of compounds which either playa vital role in agricultural, pharmaceutical and industrial contexts, or have devastating effects on agriculture, animal and human affairs by virtue of their toxigenicity. Owing to their beneficial and deleterious characteristics, these complex compounds and the genes responsible for their synthesis have been the subjects of extensive investigation by microbiologists and pharmacologists. A majority of the fungal secondary metabolic genes are classified as type I polyketide synthases (PKS) which are often clustered with other secondary metabolism related genes. In this review we discuss on the significance of our recent discovery of chalcone synthase (CHS) genes belonging to the type III PKS superfamily in an industrially important fungus, Aspergillus oryzae. CHS genes are known to playa vital role in the biosynthesis of flavonoids in plants. A comparative genome analyses revealed the unique character of A. oryzae with four CHS-like genes (csyA, csyB, csyC and csyD) amongst other Aspergilli (Aspergillus nidulans and Aspergillus fumigatus) which contained none of the CHS-like genes. Some other fungi such as Neurospora crassa, Fusarium graminearum, Magnaporthe grisea, Podospora anserina and Phanerochaete chrysosporium also contained putative type III PKSs, with a phylogenic distinction from bacteria and plants. The enzymatically active nature of these newly discovered homologues is expected owing to the conservation in the catalytic residues across the different species of plants and fungi, and also by the fact that a majority of these genes (csyA, csyB and csyD) were expressed in A. oryzae. While this finding brings filamentous fungi closer to plants and bacteria which until recently were the only ones considered to possess the type III PKSs, the presence of putative genes encoding other principal enzymes involved in the phenylpropanoid and flavonoid biosynthesis (viz., phenylalanine ammonia-lyase, cinnamic acid hydroxylase and p-coumarate CoA ligase) in the A. oryzae genome undoubtedly prove the extent of its metabolic diversity. Since many of these genes have not been identified earlier, knowledge on their corresponding products or activities remain undeciphered. In future, it is anticipated that these enzymes may be reasonable targets for metabolic engineering in fungi to produce agriculturally and nutritionally important metabolites.

• 대한환경공학회지
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• 제30권5호
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• pp.491-499
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• 2008

점점 더 강화되는 수질기준, 연료 및 에너지비용 증가 등으로 경제성, 소요부지의 최소화, 운전의 용이성, 슬러지 발생의 최소화, 높은 처리효율을 지니는 폐수처리시스템의 개발은 시급한 실정이다. 따라서 본 연구에서는 난분해성물질을 함유한 오 폐수에 대해 대기노출형 백색부후균 생물막을 이용하여 생물막의 침지형태, 체류시간, 재순환비, 모듈회전수에 따른 유기물 처리 특성을 연구하였다. HBC 링 여재에 부착된 백색부후균 생물막을 대기중에 완전히 노출하여 운전시 침지형 포기조건과 거의 비슷한 제거율을 나타냈다. 대기노출형의 최적조건은 HRT 3$\sim$4 hr, 재순환비 6$\sim$10 Q, 모듈회전수 0.5$\sim$2회/min이며, 이때 유기물 제거율은 COD$_{Cr}$ 65.0$\sim$69.9%, NBDCOD 70.4$\sim$72.7%, BOD$_5$ 88.8$\sim$90.1%, SS 84.2$\sim$90.4%를 나타냈다. 또한 본 연구에서 BOD$_5$의 유출수 평균농도는 8.9 mg/L로 중수도 수질기준 BOD$_5$ 10 mg/L이하를 만족하였으나, NBDCOD의 경우 평균농도가 29.6 mg/L로 중수도 수질기준 20 mg/L보다 높은 것으로 나타났다.