• Journal of Ecology and Environment
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• 제41권9호
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• pp.271-280
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• 2017

Background: Soil microorganisms play key roles in nutrient cycling and are distributed throughout the soil profile. Currently, there is little information about the characteristics of the microbial communities along the soil depth because most studies focus on microorganisms inhabiting the soil surface. To better understand the functions and composition of microbial communities and the biogeochemical factors that shape them at different soil depths, we analyzed microbial activities and bacterial and fungal community composition in soils up to a 120 cm depth at a fallow field located in central Korea. To examine the vertical difference of microbial activities and community composition, ${\beta}$-1,4-glucosidase, cellobiohydrolase, ${\beta}$-1,4-xylosidase, ${\beta}$-1,4-N-acetylglucosaminidase, and acid phosphatase activities were analyzed and barcoded pyrosequencing of 16S rRNA genes (bacteria) and internal transcribed spacer region (fungi) was conducted. Results: The activity of all the soil enzymes analyzed, along with soil C concentration, declined with soil depth. For example, acid phosphatase activity was $125.9({\pm}5.7({\pm}1SE))$, $30.9({\pm}0.9)$, $15.7({\pm}0.6)$, $6.7({\pm}0.9)$, and $3.3({\pm}0.3)nmol\;g^{-1}\;h^{-1}$ at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively. Among the bacterial groups, the abundance of Proteobacteria (38.5, 23.2, 23.3, 26.1, and 17.5% at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively) and Firmicutes (12.8, 11.3, 8.6, 4.3, and 0.4% at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively) decreased with soil depth. On the other hand, the abundance of Ascomycota (51.2, 48.6, 65.7, 46.1, and 45.7% at 15, 30, 60, 90, and 120 cm depths, respectively), a dominant fungal group at this site, showed no clear trend along the soil profile. Conclusions: Our results show that soil C availability can determine soil enzyme activity at different soil depths and that bacterial communities have a clear trend along the soil depth at this study site. These metagenomics studies, along with other studies on microbial functions, are expected to enhance our understanding on the complexity of soil microbial communities and their relationship with biogeochemical factors.

• 한국환경농학회지
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• 제27권2호
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• pp.133-138
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• 2008

Fire can affect microbial community structure of soil through altered environmental conditions, nutrient availability, and biotic source for microbial re-colonization. We examined the influence of fire on chemical properties and soil enzyme activities of soil for 10 months. We also characterized the soil microbial community structure through ester-linked fatty acid analysis(EL-FAME). For this study, we established five burned plots(1*1 m) and 5 unburned plots outside the margin of fire. Soil was sampled three soil cores in a each plots and composited for analysis at 1, 3, 5, 8, and 10 month after fire. The fire caused an increase in soil pH, exchangeable Ca, and Mg, organic matter, available $P_2O_5$ compared to unburned sites. The content of $NH_4-N$ in burned site was significantly higher than that of unburned site and this effect continued for 8 months after fire. There was no difference of $NO_3-N$ content in soil between burned and unburned site. Fire caused no change in acid phosphatase and arylsulfatase activities but $\beta$-glucosidase and alkaline phosphatase activities in burned site were increased compared to unburned site. Microbial biomass as estimated by total concentration of EL-FAMEs in burned sites was significantly higher than that of unburned sites at one month after fire. Burned site decreased the EL-FAMEs indicative of gram-positive bacteria and tended to increase the fatty acid associated with gram-negative bacteria at one and three months after fire. The sum of EL-FAME compound $18:2{\omega}6,9c$ and $18:1{\omega}9c$ as served fungal biomarkers was decreased in burned site compared to unburned site.

• 한국식품과학회지
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• 제12권1호
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• pp.13-17
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• 1980

토양에서 분리(分離)한 Streptomyces 속 중(中) 금속을 함유하는 푸로테아제를 강(强)하게 분비하는 균주 SY 79-1을 선별하여 그 효소학적 성질 몇가지를 조사해 본 결과는 다음과 같다. 1. 본 효소의 최적 pH는 8.0 부근이며 최적 온도는 $45^{\circ}C$였다. 2. 본 효소는 중성(中性) 부근(附近)에서는 비교적 안정하며 열처리에 대해서는 $45^{\circ}C$에서는 안정했으나 $60^{\circ}C$에서는 5분간 처리로 약 70%, 30분간 처리로 완전(完全)히 실활(失活)하였다. $Hg^{++},\;Ag^{+}Cu^{++}$ 등(等)에 의(依)해서 강하게 저해(沮害)되고, $Mg^{++},\;Mn^{++},\;Co^{++}$ 등(等)은 효소 활성을 증진 시켰으며, $Fe^{++},\;Ca^{++},\;Pb^{++},\;Al^{++} 등(等)에는 별 영향을 받지 않았다. 4. 각종 저해제 중(中) EDTA에 의해서는 강하게 저해 되었으나, 2,4-DNP, ${\rho}$-CMB, ${\varepsilon}$-aminocaproic acid thiourea, Na-arsenate, cysteine, oxalate, 구연산에 의해서는 영향을 받지 않았으며, EDTA에 의해서 저해(沮害)된 산소(酸素) 활성(活性)은 $Co_{++}$에 의해서 부활되었다.

• 한국미생물·생명공학회지
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• 제26권1호
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• pp.40-44
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• 1998

토양으로부터 갈락토스 전이활성이 우수한 $eta$-galactosidase를 생산하는 미생물을 분리하고 부분동정하여 한국종균협회에 Penicillium sp. KFCC 10888로 등록하였다. 효소는 40% 유당 용액에서 초기 유당의 73%가 전환되었을 때 70%의 높은 전이율을 보였다. 효소의 생합성은 유당에 의하여 유도되지 않았으며 배지성분으로는 콩가루가 효소 생산에 효과적이었다. 효소의 갈락토스 전이반응에 대한 최적 pH는 4.0, 최적온도는 55$^{\circ}C$이었으며, 55$^{\circ}C$에서 열안정성이 우수하였다. 갈락토올리고당의 생성량은 기질의 농도에 비례하였으며, 40%유당용액의 경우 갈락토올리고당의 함량은 고형분중 40%까지 향상되었다.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.978-989
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• 2021

Allyl isothiocyanate (AITC), as a fumigant, plays an important role in soil control of nematodes, soil-borne pathogens, and weeds, but its effects on soil microorganisms are unclear. In this study, the effects of AITC on microbial diversity and community composition of Capsicum annuum L. soil were investigated through Illumina high-throughput sequencing. The results showed that microbial diversity and community structure were significantly influenced by AITC. AITC reduced the diversity of soil bacteria, stimulated the diversity of the soil fungal community, and significantly changed the structure of fungal community. AITC decreased the relative abundance of dominant bacteria Planctomycetes, Acinetobacter, Pseudodeganella, and RB41, but increased that of Lysobacter, Sphingomonas, Pseudomonas, Luteimonas, Pseudoxanthomonas, and Bacillus at the genera level, while for fungi, Trichoderma, Neurospora, and Lasiodiplodia decreased significantly and Aspergillus, Cladosporium, Fusarium, Penicillium, and Saccharomyces were higher than the control. The correlation analysis suggested cellulase had a significant correlation with fungal operational taxonomic units and there was a significant correlation between cellulase and fungal diversity, while catalase, cellulose, sucrase, and urease were the major contributors in the shift of the community structure. Our results will provide useful information for the use of AITC in the assessment of environmental and ecological security.

• 한국해양생명과학회지
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• 제8권1호
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• pp.50-55
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• 2023

프로바이오틱스는 다양한 환경에서 분리되어 왔으며, Bacillus 균주는 유산균과 같은 일반적인 프로바이오틱스의 한계를 보완할 수 있는 내생포자 형성 능력으로 인해 프로바이오틱스 균주 중에서 유리하다. 본 연구의 목적은 한국에서 오염되지 않은 환경으로 알려진 울릉도 토양에서 분리된 Bacillus 균주의 프로바이오틱스 잠재성을 조사하는 것이다. 토양 시료는 울릉도 각지에서 채취하였으며, 항생제 내성과 효소 활성을 평가하였다. 항생제에 내성을 나타내지 않는 6개의 Bacillus 균주를 확보하였고 이후에 효소 활성을 검사하였다. 인체에 악영향을 미칠 수 있는 β-glucuronidase 효소는 활성이 나타나지 않았으며, 시중에서 판매되고 있는 Bacillus 프로바이오틱스와 유사한 효소의 활성과, 추가적으로 펩타이드 가수분해효소인 Leucine arylamidase의 활성이 나타난 NB-1 균주가 확인되었다. 이에, 추가적인 효능 연구 및 안정성 실험을 통해 프로바이오틱스 균주로서의 가능성을 모색해야 할 필요가 있다고 판단된다.

• 생태와환경
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• 제35권4호통권100호
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• pp.326-330
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• 2002

습지토양을 두 가지 방법으로 멸균한 후, 미생물 효소활성도의 변화를 알아보았다. 단기 멸균의 효과는 톨루엔을 가하여 알아 보았고, 장기적인 효과는 감마선 조사를 이용하였다. 처리된 시료에서 ${\beta}$-glucosidase, ${\beta}$-xylosidase, cellobiohydrolase, phosphatase, arylsulfatase, N -acetylglucosaminidase 활성도를 methylumbelliferyl 계열의 인공기질을 사용하여 측정한 후 공시료와 비교하였다. 톨루엔을 가한 경우 효소에 따라 다른 반응을 보였다. 예를 들어, 처리에 의하여phosphatase의 활성은 증가하였으나 반대로 ${\beta}$-glucosidase와 arylsulfatasem의 활성도는 감소하였다. 감마선 조사는 모든 효소의 활성을 40-80%정도 감소시켰다. 본 연구의 전반적인 결과에 의하면, 적어도 단기적으로는 다량의 효소가 미생물 체외에서 안정적으로 존재하나, 장기적으로는de-novo 합성이 중요함을 알 수 있었다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 춘계학술대회 및 임시총회
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• pp.43-43
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• 2014

White rot fungi have been useful source of enzymes for the degradation of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) and synthetic dyes. PAHs are widespread organic compounds present in fossil fuels and are routinely generated by incomplete fuel combustion. PAHs are some of the major toxic pollutants of water and soil environments. Synthetic dyes are major water-pollutants, which are toxic to organisms in water environments and interfere photosynthesis of water plants. Removal of PAHs and synthetic dyes has been of interests in the environmental science especially in the environmental microbiology. Mushrooms are fungal groups that function as primary degraders of wood polyphenolic lignin. The ligninolytic enzymes produced by mushroom, including manganese peroxidase, lignin peroxidase, and laccase, mediate the oxidative degradation of lignin. The catalytic power of these enzymes in the degradation of aromatic ring compounds has been sought for the degradation of various organic compounds. In this project, we have screened 60 wild mushroom strains for their degradation activity against two representative PAHs, naphthalene and anthracene, and five aromatic dyes, including alizarin red S, crystal violet, malachite green, methylene blue, rose bengal. The degradation of PAHs was measured by GC while the decolorization of dyes was measured by both UV spectrophotometer and HPLC. As results, 9 wild mushroom strains showed high activity in degradation of PAHs and textile dyes. We also describe the secretive enzyme activities, the transcription levels, and cloning of target genes. In conjunction with this, activities of degradative enzymes, including laccase, lignin peroxidase, and Mn peroxidase, were measured in the liquid medium in the presence of PAHs and dyes. Our results showed that the laccase activity was directed correlated with the degradation, indicating that the main enzyme acts on PAHs and dyes is the laccase. The laccase activity was further simulated by the addition of $Cu^{2+}$ ion. Detailed studies of the enzyme system should be sought for future applications.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.124-128
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• 2003

대전광역시 근교의 야산과 들판 등지에서 썩은 나뭇잎, 짚, 흙을 채취하여 각각을 배양한 다음 Congo red test에 의해 cellulase 활성을 보이는 균주를 선별하였다. Genomic DNA를 분리한 후 PCR을 수행하여 DNA sequence를 Gene Bank를 통해 분석한 결과 A. tubingensis로 밝혀졌다. 이것을 배양하여 상등액을 crude enzyme으로 사용하여 온도와 pH를 달리하면서 효소의 활성정도를 측정하였다. 대조균주로 A. oryzae KCTC 6291를 이용하였고, 본 연구를 통하여 분리한 균주인 A. tubingensis가 생산하는 cellulase는 A. oryzae의 cellulase에 비하여 각각 다른 온도와 pH에서 높은 안정성을 보여주었다. A. tubingensis는 각각의 온도에서 활성의 정도가 비슷했으며, 45$^{\circ}C$, 55$^{\circ}C$에서 높은 활성을 나타내고 있지만, 고르게 활성이 나타났다. 또한 pH 12.0에서 가장 높은 활성을 보여 주었고, pH 2.0, 3.0, 4.0에서는 양쪽 모두 거의 활성이 없었으며, 중성, 염기성에 대해서 활성에는 큰 변화가 없었다. 따라서, 분리 동정한 A. tubingensis는 온도와 pH에서 고르게 활성을 나타내므로 생균제로 활용할 수 있는 범위가 클 것으로 여겨진다.

• 한국환경농학회지
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• 제30권3호
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.