• Journal of Microbiology and Biotechnology
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• 제30권2호
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• pp.155-162
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• 2020

Acetyl xylan esterase (AXE; E.C. 3.1.1.72) is one of the accessory enzymes for xylan degradation, which can remove the terminal acetate residues from xylan polymers. In this study, two genes encoding putative AXEs (LaAXE and BhAXE) were cloned from Lactobacillus antri DSM 16041 and Bacillus halodurans C-125, and constitutively expressed in Escherichia coli. They possess considerable activities towards various substrates such as p-nitrophenyl acetate, 4-methylumbelliferyl acetate, glucose pentaacetate, and 7-amino cephalosporanic acid. LaAXE and BhAXE showed the highest activities at pH 7.0 and 8.0 at 50℃, respectively. These enzymes are AXE members of carbohydrate esterase (CE) family 7 with the cephalosporine-C deacetylase activity for the production of antibiotics precursors. The simultaneous treatment of LaAXE with Thermotoga neapolitana β-xylanase showed 1.44-fold higher synergistic degradation of beechwood xylan than the single treatment of xylanase, whereas BhAXE showed no significant synergism. It was suggested that LaAXE can deacetylate beechwood xylan and enhance the successive accessibility of xylanase towards the resulting substrates. The novel LaAXE originated from a lactic acid bacterium will be utilized for the enzymatic production of D-xylose and xylooligosaccharides.

• 한국환경과학회지
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• 제24권9호
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• pp.1221-1231
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• 2015

The present study was conducted to find a way to recycle the coir substrate by investigating changes in its physical and chemical properties based on the number of use year. Specific gravity of unused coir substrate was $0.212g/cm^3$, while it was higher for the substrate used for 2 years. Porosity was different depending on the number of use year. The porosity of unused substrate was 51.9%, but it increased to 68.6% after used for 2 years. In general, physical and chemical properties were better in the coir substrate used for 2 years than in unused one. The number of leaves, leaf area, flesh weight and dry weight of oriental cabbage and lettuce were higher in coir substrate used for 2 years than those in unused one. Whereas, no significant difference was observed between the substrates used for one year and 2 years, indicating that the one time-used wast substrate could be recycled for cultivating vegetables. Growth of the vegetables was improved when organic fertilizer composed of complex organics with different mixing ratios was provided to the coir substrate, compared to untreated plot. The optimum mixing ratio of the wast substrate and complex organics was 2:8(v/v) for fertilization using wast coir substrate. Therefore, coir substrate generally wasted after being used for one time was reuseable by supplying organic fertilizer.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.272-279
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• 2021

Two genes encoding probable α-ʟ-arabinofuranosidase (E.C. 3.2.1.55) isozymes (ABFs) with 92.3% amino acid sequence identity, ABF51A and ABF51B, were found from chromosomes 3 and 5 of Saccharomycopsis fibuligera KJJ81, an amylolytic yeast isolated from Korean wheat-based nuruk, respectively. Each open reading frame consists of 1,551 nucleotides and encodes a protein of 517 amino acids with the molecular mass of approximately 59 kDa. These isozymes share approximately 49% amino acid sequence identity with eukaryotic ABFs from filamentous fungi. The corresponding genes were cloned, functionally expressed, and purified from Escherichia coli. SfABF51A and SfABF51B showed the highest activities on p-nitrophenyl arabinofuranoside at 40~45℃ and pH 7.0 in sodium phosphate buffer and at 50℃ and pH 6.0 in sodium acetate buffer, respectively. These exoacting enzymes belonging to the glycoside hydrolase (GH) family 51 could hydrolyze arabinoxylo-oligosaccharides (AXOS) and arabino-oligosaccharides (AOS) to produce only ʟ-arabinose, whereas they could hardly degrade any polymeric substrates including arabinans and arabinoxylans. The detailed product analyses revealed that both SfABF51 isozymes can catalyze the versatile hydrolysis of α-(1,2)- and α-(1,3)-ʟ-arabinofuranosidic linkages of AXOS, and α-(1,2)-, α-(1,3)-, and α-(1,5)-linkages of linear and branched AOS. On the contrary, they have much lower activity against the α-(1,2)- and α-(1,3)-double-substituted substrates than the single-substituted ones. These hydrolases could potentially play important roles in the degradation and utilization of hemicellulosic biomass by S. fibuligera.

• 농업과학연구
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• 제40권3호
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• pp.203-208
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• 2013

Differences in the filling amount of substrates in container can influence severely on the soil physical properties and crop growth. This research was conducted to secure the fundamental informations related to the changes in soil physical properties as influenced by the filling amount of coir dust-based substrates in container. For the experiment, three substrates were formulated by blending coir dust (CD) with expanded rice hull (CD+ERH, 8:2, v/v), carbonized rice hull (CD+CRH, 6:4, v/v) or ground and aged pine bark (CD+GAPB, 8:2, v/v). Based on the optimum bulk density, the amount of substrates filled in 347.5mL aluminum cylinder were adjusted to 90, 100, 110, 120, and 130%. Then the changes in total porosity (TP), container capacity (CC), and air-filled porosity (AFP) by various filling amounts were measured. The TP decreased linearly in CD+ERH and CD+GAPB and quadratically in CD+CRH as the filling amounts of the media increased from 90% to 130%. The CC in CD+ERH and CD+GAPB media increased as the filling amount increased from 90% to 120%, then decreased in 130%, showing quadratic change. The CC in CD+CRH was the highest in 90% filling amount and decreased gradually as the filling amount of root medea increased. The AFPs in CD+ERH and CD+GAPB media were 38 and 37%, respectively in 90% filling amount and they decreased drastically until 110% filling, then gradually in 120 and 130% filling amount showing the quadratic changes. The AFP of CD+CRH at 90% filling amount was 22% and it decreased as the filling amount increased until 130%, showing linear change. These results indicate that the increase in filling amount of substrates influenced more severely the AFP than CC, and careful consideration on container filling is required to provide a better root condition thus maximize crop growth.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.43-43
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• 2019

Deparia pycnosora (Christ) M. Kato is a fern used as ornamental plant. In addition, it is called "Teol-go-sa-ri" in Korean name. The aim of this study was to develop a practical propagation method of D. pycnosora using tissue culture technique. Prothallus obtained from spore germination was the used as experiment materials. The prothalli (300 mg) used in all experiments were sub-cultured for 8-week intervals. The most suitable media for prothallus propagation were identified by culturing 300 mg of prothalli in $1/4{\times}$, $1/2{\times}$, $1{\times}$, $2{\times}$ MS medium and in Knop medium for 8 weeks. Also, the prothalli were cultured by chopping with a scalpel. In addition, sucrose, activated charcoal, and total nitrogen source were added in different concentrations based on the culture medium selected. Cultures were maintained at a temperature of $25{\pm}1^{\circ}C$, light intensity of $30{\times}1.0{\mu}mol-m-2{\cdot}s-1$, and a photoperiod of 16/8 h (light/dark) in in vitro. The results showed that optimum was achieved prothallus fresh weight and development in $1{\times}$ MS medium. When other components were added to the basic $1{\times}$ MS medium, prothallus propagation was maximized in $1{\times}$ MS medium supplemented with 2% sucrose, 0.2% activated charcoal, and 60 mM total nitrogen. To select a suitable soil mixture for sporophyte formation, 1.0 g of prothallus was blended with distilled water, spread on five combinations of different soil substrates (decomposed granite, horticultural substrates, peat moss, and perlite), and cultivated for 12 weeks. The sporophyte cultures were maintained at a temperature of $25{\pm}1^{\circ}C$, light intensity of $43{\pm}2.0{\mu}mol-m-2{\cdot}s-1$, humidity of $84{\pm}1.4%$, and a photoperiod of 16/8 h (light/dark). As a results, horticultural substrate alone, 2:1 (v:v) mixtures of horticultural substrate and perlite, and 2:1 mixtures of horticultural substrate and decomposed granite induced 208.0, 201.3 and 248.8 sporophytes per pot, respectively. Therefore, this result could provide a practical mass propagation method of D. pycnosora

• 원예과학기술지
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• 제29권2호
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• pp.95-101
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• 2011

코코피트 + 펄라이트(5:5, A), 코코피트 + 펄라이트(6:4, B), 코코피트 + 펄라이트(7:3, C), 코코피트 + 코코칩(7:3, D), 코코피트 + 코코칩(6:4, E), 그리고 피트모스 + 버미큘라이트(5:5, F)의 6종류 상토를 혼합하고 플라스틱 백에 충전하였다. 다음 '설향' 딸기의 모주를 재배하면서 상토 물리 화학성이 모주 생육과 자묘 발생에 미치는 영향을 구명하기 위하여 본 연구를 수행하였다. 본 연구에서 조제된 모든 상토는 공극률이 85% 이상, 용기용수량이 55% 이상으로 측정되어 모든 상토가 수용 가능한 범위에 포함되었지만, F 상토의 공극률과 용기용수량이 각각 91.5% 및 60%로 다른 상토들보다 뚜렷하게 높았다. '설향' 딸기의 정식 전 또는 작물을 수확한 후 분석한 상토의 화학성에서 상토 A, B, C, 및 F의 전기전도도 및 질산태 질소 농도가 상토 D 또는 E보다 높았다. 또한 염 농도가 높았던 상토 A, B, C, 및 F의 런너 생체중, 건물중, 및 길이 그리고 자묘 발생수가 염농도가 낮았던 상토 D 및 E보다 많았으며, 상토의 물리성 보다 화학성이 런너의 생장 및 자묘 발생에 더 큰 영향을 미쳤다. '설향' 딸기의 정식 120일 후 지상부 전체의 무기물 함량을 분석한 결과에서 질소함량은 F 상토를 제외한 다른 상토들 간에 유의차를 발견할 수 없었는데, 이는 주정리를 통해 하위엽을 제거해준 것이 원인이 되었다고 판단하였다. 분석한 다른 원소의 식물체내 함량도 F 상토에서 뚜렷하게 높아 화학성이 자묘 발생에 큰 영향을 미침을 알 수 있었다.

• 한국균학회지
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• 제38권2호
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• pp.136-141
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• 2010

본 시험은 버섯 병재배 농가에서 사용하고 있는 배지재료와 혼합배지의 수분함량, pH, 전탄소(T-C), 전질소(T-N), C/N율, 인산, 13종의 양이온 함량 등 이화학적 특성을 파악하여 기초자료로 활용하고자 수행하였다. 전국의 병재배 농가에서 임의로 선정한 35농가 중 팽나무버섯 13개소, 큰느타리버섯 14개소, 느타리버섯 8개소에서 배지재료 143점과 혼합배지 35점의 시료가 수집되었다. 배지재료의 성분함량은 동일한 명칭의 재료라도 2~5배로 차이가 많은 경우도 있었다. 그리고 농가에서 수집한 버섯재배용 혼합배지의 C/N율은 팽나무버섯과 큰 느타리버섯 배지가 $28{\pm}4$, 느타리버섯 병재배용 배지는 $21{\pm}2$의 범위이었으며 중금속 등 특정성분에 특이사항은 없었다. 그리고 배지재료별 성분함량표를 이용하여 버섯 재배용 혼합배지의 성분조성을 산출하기 위한 계산식을 제시하였다.

• 원예과학기술지
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• 제28권6호
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• pp.964-972
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• 2010

피트모스+버미큘라이트(5:5, A), 피트모스+펄라이트(7:3, B), 코코피트+펄라이트(7:3, C), 코코피트+피트모스+펄라이트(3.5:3.5:3.0, D), 왕겨+코코피트+펄라이트(2:7:1, E), 그리고 왕겨+코코피트(3:7, F)의 6종류 상토를 혼합하여 상부 직경 10cm의 플라스틱 포트에 충전한 후 '설향' 딸기의 모주에서 발생한 런너를 고정시켜 번식시키면서 상토 물리 화학성이 자묘 생육에 미치는 영향을 구명하기 위하여 본 연구를 수행하였다. 자묘 육묘용 상토의 용기용수량과 기상률은 상토별 차이가 뚜렷하였으며 E와 F 상토는 용기용수량이 낮고 기상률이 높아 상토의 수분관리에 어려움이 있을 것으로 판단하였다. 피트모스가 혼합된 상토 A, B, 및 D의 질소농도가 높았고, 왕겨를 혼합한 상토 E와 F의 질소 및 인산 농도가 낮았다. 또한 코코피트가 혼합된 상토가 피트모스가 혼합된 상토 보다 K 농도가 월등히 높았다. A상토에서 '설향' 자묘를 재배한 결과 약 13mm에서 관부직경의 회귀선이 형성되어 가장 굵었고, F, B와 C 상토에서 육묘한 자묘도 관부 직경의 회귀선이 약 10mm 이상에서 형성되고 있어 자묘의 생육에 바람직하다고 판단하였다. '설향' 자묘의 생체중은 A 상토에서 육묘한 경우 식물체당 10g 후반에서 회귀선이 형성되었지만, C, F, D, E, 그리고 B 상토의 순으로 가벼워졌다. '설향' 자묘의 건물중도 생체중과 유사한 경향을 보였으며 A, C 및 F 상토에서 비교적 건물중 생산량이 많았고, B 상토에서 적었다. 생체중과 건물중 생산량이 많을 경우 보편적으로 식물이 건전한 생육을 하고 있음을 의미하며, 이러한 판단을 적용할 때 A, C 및 F 상토가 자묘생육을 위해 바람직하다고 판단하였다.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.187-194
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• 2022

Two α-ʟ-arabinofuranosidases (BfdABF1 and BfdABF3) and a β-ᴅ-xylosidase (BfdXYL2) genes were cloned from Bifidobacterium dentium ATCC 27679, and functionally expressed in E. coli BL21(DE3). BfdABF1 showed the highest activity in 50 mM sodium acetate buffer at pH 5.0 and 25℃. This exo-enzyme could hydrolyze p-nitrophenyl arabinofuranoside, arabino-oligosaccharides (AOS), arabinoxylo-oligosaccharides (AXOS) such as 3²-α-ʟ-arabinofuranosyl-xylobiose (A³X), and 2³-α-ʟ-arabinofuranosyl-xylotriose (A²XX), whereas hardly hydrolyzed polymeric substrates such as debranched arabinan and arabinoxylans. BfdABF1 is a typical exo-ABF with the higher specific activity on the oligomeric substrates than the polymers. It prefers to α-(1,2)-ʟ-arabinofuranosidic linkages compared to α-(1,3)-linkages. Especially, BfdABF1 could slowly hydrolyze 2³,3³-di-α-ʟ-arabinofuranosyl-xylotriose (A²⁺³XX). Meanwhile, BfdABF3 showed the highest activity in sodium acetate at pH 6.0 and 50℃, and it has the exclusively high activities on AXOS such as A³X and A²XX. BfdABF3 mainly catalyzes the removal of ʟ-arabinose side chains from various AXOS. BfdXYL2 exhibited the highest activity in sodium citrate at pH 5.0 and 55℃, and it specifically hydrolyzed p-nitrophenyl xylopyranoside and xylo-oligosaccharides (XOS). Also, BfdXYL2 could slowly hydrolyze AOS and AXOS such as A³X. Based on the detailed hydrolytic modes of action of three exo-hydrolases (BfdABF1, BfdABF3, and BfdXYL2) from Bf. dentium, their probable roles in the hemiceullose-utilization system of Bf. dentium are proposed in the present study. These intracellular exo-hydrolases can synergistically produce ʟ-arabinose and ᴅ-xylose from various AOS, XOS, and AXOS.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.37-43
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• 2019

The gene encoding an ${\alpha}-{\text\tiny{L}}-arabinofuranosidase$ (BvAF) GH51 from Bacillus velezensis FZB42 was cloned and expressed in Escherichia coli. The corresponding open reading frame consists of 1,491 nucleotides which encode 496 amino acids with the molecular mass of 56.9 kDa. BvAF showed the highest activity against sugar beet (branched) arabinan in 50 mM sodium acetate buffer (pH 6.0) at $45^{\circ}C$. However, it could hardly hydrolyze debranched arabinan and arabinoxylans. The time-course hydrolyses of branched arabinan and arabinooligosaccharides (AOS) revealed that BvAF is a unique exo-hydrolase producing exclusively ${\text\tiny{L}}-arabinose$. BvAF could cleave ${\alpha}-(1,2)-$ and/or ${\alpha}-(1,3)-{\text\tiny{L}}-arabinofuranosidic$ linkages of the branched substrates to produce the debranched forms of arabinan and AOS. Although the excessive amount of BvAF could liberate ${\text\tiny{L}}-arabinose$ from linear AOS, it was extremely lower than that on branched AOS. In conclusion, BvAF is the arabinan-specific exo-acting ${\alpha}-{\text\tiny{L}}-arabinofuranosidase$ possessing high debranching activity towards ${\alpha}-(1,2)-$ and/or ${\alpha}-(1,3)-linked$ branches of arabinan, which can facilitate the successive degradation of arabinan by $endo-{\alpha}-(1,5)-{\text\tiny{L}}-arabinanase$.