• 한국미생물·생명공학회지
• /
• 제40권1호
• /
• pp.30-38
• /
• 2012

두 종의 Bacillus와 한 종의 Pseudomonas로 구성된 컨소시엄 미생물제제를 고추 경작지에 첨가하였을 때 경작지 토양의 미생물 다양성 변화를 조사하기 위해 건전한 토양의 지표가 되는 질소순환관여 미생물과 근권토양 내 섬유소 분해기능, 인산가용화기능과 urea 가수분해기능을 가지는 기능성미생물의 활성과 밀도를 측정하였다. 고추 경작지 토양에 컨소시엄 PGPR 미생물인 B. subtilis AH18, B. licheniformis K11과 P. fluorescens 2112의 컨소시엄 미생물제제를 처리하여 토양미생물의 다양성에 변화를 측정하여 컨소시엄 미생물제제의 처리에 의한 근권토양 미생물의 다양성 변화와 고추의 생육에 미치는 영향을 분석하였다. 컨소시엄 미생물제제 처리구의 경우 Actinomyces spp., Trichoderma spp., 광합성세균과 Azotobacter spp.가 다른 처리구에 비하여 1.7-5배 이상 높았으며, 질소 순환에 관여하는 미생물은 1.4-4배 증가되었다. 또한 기능성 미생물의 다양성도 화학제제나 물처리구와 비교하였을 때 1.3-3배 증가하였다. 건고추 수확량은 컨소시엄 미생물제제를 처리하였을 경우 대조구나 화학제제를 처리하였을 때보다 15%이상 수확량이 증대되었다. 따라서 PGPR 컨소시엄 미생물제제의 처리로 인해 고추 경작지 토양의 근권미생물 다양성과 작물의 생산성에 긍정적인 영향을 주는 것으로 생각된다. 추후 메타지노믹스를 활용하여 미생물 다양성 변화를 추가적으로 확인할 예정이다.

• 한국미생물·생명공학회지
• /
• 제37권1호
• /
• pp.1-9
• /
• 2009

식물성장촉진물질인 auxin을 비롯한 식물병원성진균을 방제하는 siderophore 그리고 식물병원성 진균의 세포벽을 분해하는 cellulase를 동시에 생산하는 생물방제균주 B. subtilis AH18의 토양내 monitoring을 위하여 각 생산물질에 관여하는 유전자를 기초로 primer(sid, aec, cel)를 제작하였다. Single PCR 및 multiplex PCR을 수행하여 800-bp(sid), 1000-bp(air), 1600-bp(cel)의 DNA fragment를 확인하였으며, 각각의 fragment는 siderophore의 생합성 key enzyme인 2,3-dihydro-2,3-dihydroxy benzoate dehydrogenase[EC : 1. 3. 1, 28]gene (sid-794bp)이며, auxin efflux carrier gene (aec - 1052 bp), 그리고 cellulase gene(cel - 1582 bp)임을 확인하고, NCBI Genbank에 등록하였다(Genbank accession sid: No. EF408238, aec: No. EF408239, cel: No. EF070194). 또한 B. subtilis AH18을 처리한 일반 경작지 토양에서 multiplex PCR을 통하여 3종의 유전자에서 증폭된 triple band를 확인하였으며, 고추를 실제 토양을 이용해 Pot에 이식 후 고추의 rhizosphere와 non-rhizosphere에서 B. subtilis AH18의 존재를 확인할 수 있다. 뿐만아니라 본 균주를 고추가 이식된 Pot의 토양에 처리 후 monitoring시 민감도는 $1.8\times10^5$ cfu/g이었고, monitoring 가능한 기간은 3주이상 확인 할 수 있었다.

• 생명과학회지
• /
• 제15권6호
• /
• pp.851-856
• /
• 2005

Although valuable microbes have been isolated from the soil for the various productions of useful components, the microbes which can be cultivated in the laboratory are only $0.1-1\%$ of all microbes. To solve this problem, the study has recently been tried for making the valuable components from the environment by directly separating unculturable micrbial DNA in the soil. But it is known that humic acid originated from the soil interrupts various restriction enzymes and molecular biological process. Thus, in order to prevent these problems, this study modified the method separated soil DNA with phenol, CTAB and PEG. In order to compare the degree of purity for each DNA and the molecular biological application process, $A_{260}/A_{280}$ ratio, restriction enzymes, and PCR were performed. In case of DNA by the modified method, total yield of DNA was lower but $A_{260}/A_{280}$ ratio was higher than the previously reported methods. It was confirmed that the degree of purity is improved by the modified method. But it was not cut off by all kinds of tested restriction enzymes because of the operation of a very small amount of interrupting substances. When PCR was operated with each diluted DNA in different concentrations and GAPDH primer, the DNA by the modified method could be processed for PCR in the concentration of 100 times higher than by the previously reported separation method. Therefore, this experiment can find out the possibility of utilization for the unknown substances by effectively removing the harmful materials including humic acid and help establishing metagenomic DNA library from the soil DNA having the high degree of purity.

• 미생물학회지
• /
• 제14권4호
• /
• pp.159-166
• /
• 1976

This study was carried out for the identification of several fungi isolated from some different geographic regional soil samples and evaluation of its pathgenicity to the mice. isolates, The results were isolated from 200 soil samples and 11 strains from 25 pigeon excreta. 2. Seventeen of Cryptococcus neoformans, eight of Candida albicans and Microporum gypseum, six of M. coorei, and three of Sporothrix schencrii were identified group. 3. An association of C. neoformans with avian habitats was found. Ten of the 11 isolates came from areas frequently by pigeons such as pigeon nest and pigeon excreta. 4. The inflammatory reaction produced in mice that were inoculated with C. neoformans and C. albicans intraperitoneal route.

• Journal of Microbiology and Biotechnology
• /
• 제26권10호
• /
• pp.1717-1722
• /
• 2016

A novel phytase of Acidobacteria was identified from a soil metagenome, cloned, overexpressed, and purified. It has low sequence similarity (<44%) to all the known phytases. At the optimum pH (2.5), the phytase shows an activity level of 1,792 μmol/min/mg at physiological temperature (37℃) and could retain 92% residual activity after 30 min, indicating the phytase is acidophilic and acidostable. However the phytase shows poor stability at high temperatures. To improve its thermal resistance, the enzyme was redesigned using Disulfide by Design 2.0, introducing four additional disulfide bridges. The half-life time of the engineered phytase at 60℃ and 80℃, respectively, is 3.0× and 2.8× longer than the wild-type, and its activity and acidostability are not significantly affected.

• Journal of Microbiology and Biotechnology
• /
• 제28권5호
• /
• pp.831-838
• /
• 2018

Trophic interactions of introduced biocontrol fungi with soil animals can be a key determinant in the fungal proliferation and activity. This study investigated the trophic interaction of an introduced biocontrol fungus with soil nematodes. The biocontrol fungus Trichoderma harzianum ThzID1-M3 and the fungivorous nematode Aphelenchoides sp. (10 per gram of soil) were added to nonsterile soil, and microbial populations were monitored for 40 days. Similar results were obtained when the experiment was duplicated. ThzID1-M3 stimulated the population growth of indigenous nematodes (p < 0.05), regardless of whether Aphelenchoides sp. was added. Without ThzID1-M3, indigenous nematodes did not increase in number and the added Aphelenchoides sp. nematodes almost disappeared by day 10. With ThzID1-M3, population growth of nematodes was rapid between 5 and 10 days after treatment. ThzID1-M3 biomass peaked on day 5, dropped at day 10, and then almost disappeared at day 20, which was not influenced by the addition of nematodes. In contrast, a large quantity of ThzID1-M3 hyphae were present in a heat-treated soil in which nematodes were eliminated. Total fungal biomass in all treatments peaked on day 5 and subsequently decreased. Addition of nematodes increased the total fungal biomass (p < 0.05), but ThzID1-M3 addition did not affect the fungal biomass. Hyphae of total fungi when homogenously distributed did not support the nematode population growth; however, hyphae of the introduced fungus did when densely localized. The results suggest that soil fungivorous nematodes are an important constraint on the hyphal proliferation of fungal agents introduced into natural soils.

• 미생물학회지
• /
• 제32권2호
• /
• pp.163-171
• /
• 1994

경유를 sandy loam 토양에서 농도별로 투여하여 토양미생물군집에 미치는 영향을 조사하였으며 또한 경우가 첨가된 토양에서 경유의 신속한 제거를 위해 실시한 bioremediation에 의한 영향을 측정하였다. 경유는 토양에서 16주 후 약 50% 내외의 잔류량을 나타내며 bioremediation 처리시 제거율은 60~95% 정도가 증가하여 16주 후 약 8~20 범위의 잔류량을 나타내었다. 토양에 경유가 첨가되었을 때에는 세균직접계수, 진균류의 균사 길이, 호기성 종속영양세균과 탄화수소 분해세균의 수가 최고 10 내지 100배 정도 증가하였다. Bioremediation 처리시에는 그 증가가 더욱 두드러져 각종 미생물 개체수 측정치가 최고 100배 내지 1000배까지 증가하였다. 경유가 fluorescein diacetate 가수분해 활성에 미치는 영향은 bioremediation 처리를 하지 않은 토양에서는 뚜렷한 증감의 경향이 없었으나 bioremediation 처리를 한 토양에서는 10배 내외의 활성의 증가를 보였으며 이러한 양상은 soil dehydrogenase 활성에서도 유사하게 나타났다.

• 한국생명과학회:학술대회논문집
• /
• 한국생명과학회 2001년도 10주년 기념 국제학술 심포지움 및 추계학술대회
• /
• pp.26-29
• /
• 2001

• 한국미생물·생명공학회지
• /
• 제24권4호
• /
• pp.399-403
• /
• 1996

Total 938 actinomycete strains were isolated from 59 soil samples collected at Cheju island. All of these isolates were identified to the genus level based on morphological and physiological characteristics. As the result, 62.6% of those isolates were Streptomyces, 16.4% were Micromonospora, 8.6% were Nocardioform group, 2.2% were Actinomadura, 1.7% were Microbispora, 1.6% were Nocardiopsis, 1.0% were Streptosporangium, and 5.9% were the others. As the sources of soil, Streptomyces and Microbispora were abundant in grassland soil, Streptomyces and Micromonospora were abundant in field soil, and Micromonospora were abundant in forest soil. Especially, Nocardioform strains were abundant in natural caves.

• Journal of Microbiology and Biotechnology
• /
• 제27권12호
• /
• pp.2199-2210
• /
• 2017

Soil burial is the most widely used disposal method for infected pig carcasses, but composting has gained attention as an alternative disposal method because pig carcasses can be decomposed rapidly and safely by composting. To understand the pig carcass decomposition process in soil burial and by composting, pilot-scale test systems that simulated soil burial and composting were designed and constructed in the field. The envelope material samples were collected using special sampling devices without disturbance, and bacterial community dynamics were analyzed by high-throughput pyrosequencing for 340 days. Based on the odor gas intensity profiles, it was estimated that the active and advanced decay stages were reached earlier by composting than by soil burial. The dominant bacterial communities in the soil were aerobic and/or facultatively anaerobic gram-negative bacteria such as Pseudomonas, Gelidibacter, Mucilaginibacter, and Brevundimonas. However, the dominant bacteria in the composting system were anaerobic, thermophilic, endospore-forming, and/or halophilic gram-positive bacteria such as Pelotomaculum, Lentibacillus, Clostridium, and Caldicoprobacter. Different dominant bacteria played important roles in the decomposition of pig carcasses in the soil and compost. This study provides useful comparative date for the degradation of pig carcasses in the soil burial and composting systems.