• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
• /
• pp.100-107
• /
• 2000

In a recently developed strategy for in-situ treatment of polychlorinated biphenyls (PCB), bioaugmentation was used in conjunction with a surfactant, sorbitan trioleate, as a carbon source for the degrader bacteria, along with the monoterpene, carvone, and salicylic acid as inducing substrates. Two bacteria were used for soil inoculants, including Arthrobacter sp. st. B1B and Ralstonia eutrophus H850. This methodology achieved 60% degradation of PCBs in Aroclor 1242 after 18 weeks in soils receiving 34 repeated applications of the degrader bacteria. However, an obvious limitation was the requirement for soil mixing after every soil inoculation. In the research reported here, bioaugmentation and biostimulation treatment strategies were modified by using the earthworm, Pheretima hawayana, as a vector for dispersal and mixing of surface-applied PCB-degrading bacteria and soil chemical amendments. Changes in microbial biomass and microbial community structure due to earthworm effects were examined using DNA extraction and PCR-DGGE of 16S rDNA. Results showed that earthworms effectively promoted biodegradation of PCBs in bioaugmented soils to the same extent previously achieved using physical soil mixing, and had a lesser, but significant effect in promoting PCB biodegradation in biostimulated soils treated with carvone and salicylic acid. The effects of earthworms were speculated to involve many interacting factors including increased bacterial transport to lower soil depths, improved soil aeration, and enhanced microbial activity and diversity.

• Journal of Microbiology and Biotechnology
• /
• 제32권3호
• /
• pp.294-301
• /
• 2022

In our greenhouse experiment, soil heat treatment groups (50, 80, and 121℃) significantly promoted growth and disease suppression of Panax notoginseng in consecutively cultivated soil (CCS) samples (p < 0.01), and 80℃ worked better than 50℃ and 121℃ (p < 0.01). Furthermore, we found that heat treatment at 80℃ changes the microbial diversity in CCS, and the inhibition ratios of culturable microorganisms, such as fungi and actinomycetes, were nearly 100%. However, the heat-tolerant bacterial community was preserved. The 16S rRNA gene and internal transcribed spacer (ITS) sequencing analyses indicated that the soil heat treatment had a greater effect on the Chao1 index and Shannon's diversity index of bacteria than fungi, and the relative abundances of Firmicutes and Proteobacteria were significantly higher than without heating (80 and 121℃, p < 0.05). Soil probiotic bacteria, such as Bacillus (67%), Sporosarcina (9%), Paenibacillus (6%), Paenisporosarcina (6%), and Cohnella (4%), remained in the soil after the 80℃ and 121℃ heat treatments. Although steam increased the relative abundances of most of the heat-tolerant microbes before sowing, richness and diversity gradually recovered to the level of CCS, regardless of fungi or bacteria, after replanting. Thus, we added heat-tolerant microbes (such as Bacillus) after steaming, which reduced the relative abundance of pathogens, recruited antagonistic bacteria, and provided a long-term protective effect compared to the steaming and Bacillus alone (p < 0.05). Taken together, the current study provides novel insight into sustainable agriculture in a consecutively cultivated system.

• 한국미생물학회:학술대회논문집
• /
• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
• /
• pp.188.4-188
• /
• 2005

• 한국농림기상학회:학술대회논문집
• /
• 한국농림기상학회 2012년도 학술발표논문집
• /
• pp.161-164
• /
• 2012

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• 제4권2호
• /
• pp.86-94
• /
• 2023

Climate change is more rapid in the Arctic than elsewhere in the world, and increased precipitation and warming are expected cause changes in biogeochemical processes due to altered microbial communities and activities. It is crucial to investigate microbial responses to climate change to understand changes in carbon and nitrogen dynamics. We investigated the effects of increased temperature and precipitation on microbial biomass and community structure in dry tundra using two depths of soil samples (organic and mineral layers) under four treatments (control, warming, increased precipitation, and warming with increased precipitation) during the growing season (June-September) in Cambridge Bay, Canada (69°N, 105°W). A phospholipid fatty acid (PLFA) analysis method was applied to detect active microorganisms and distinguish major functional groups (e.g., fungi and bacteria) with different roles in organic matter decomposition. The soil layers featured different biomass and community structure; ratios of fungal/bacterial and gram-positive/-negative bacteria were higher in the mineral layer, possibly connected to low substrate quality. Increased temperature and precipitation had no effect in either layer, possibly due to the relatively short treatment period (seven years) or the ecosystem type. Mostly, sampling times did not affect PLFAs in the organic layer, but June mineral soil samples showed higher contents of total PLFAs and PLFA biomarkers for bacteria and fungi than those in other months. Despite the lack of response found in this investigation, long-term monitoring of these communities should be maintained because of the slow response times of vegetation and other parameters in high-Arctic ecosystems.

• 한국토양비료학회지
• /
• 제45권5호
• /
• pp.829-835
• /
• 2012

경제적 및 농업적 장점은 유전자 변형 작물 재배면적의 증가를 가져왔다. 그러나 유전자 변형 작물의 상업적 재배전에 유전자 변형 작물의 인간건강 및 환경에 미칠 잠재적 위해성에 대한 면밀한 검토가 필수적이다. 본 연구에서는 Bt벼의 토양미생물 군집에 미치는 영향을 조사하였다. 토양화학성분을 분석한 결과, Bt벼와 낙동벼 근권토양 간 화학성분의 유의성 있는 차이는 없는 것으로 조사되었다. 재배전, 재배초기, 최고분얼기의 토양미생물 군집밀도를 조사했을 때 Bt벼 근권토양의 세균, 방선균, 진균 군집밀도는 낙동벼와 유사한 수준으로 나타났다. 시기별 DGGE 분석결과 Bt 벼 근권토양 전체미생물상은 낙동벼와 차이가 없는 것으로 조사되었다. Pyrosequencing을 통한 Bt벼와 낙동벼의 미생물 군집조성을 조사한 결과 주요 미생물상 분포에 있어서도 매우 유사한 양상을 나타내었다. 위의 결과들을 종합해볼때 Bt 재배에 따른 토양미생물상에 미치는 영향은 미미한 것으로 사료된다. 수확 후 벼 잔존물이 토양환경에 미치는 영향에 대해서는 좀 더 연구가 진행되어야 할 것이다.

• 자원환경지질
• /
• 제57권3호
• /
• pp.305-317
• /
• 2024

토양 내 미생물 군집의 변화가 비소 용출에 미치는 영향을 파악하기 위해 비소 오염 토양(F1, G7, G10)을 대상으로 실험을 수행하였다. 실험은 혐기적 조건에서 비소 오염 토양을 ① BAC: 멸균토양 + Bacillus fungorum, ② IND: 토착균 토양, ③ MIX: 토착균 토양 + B. fungorum으로 나누어 혐기적 조건에서 유산염을 탄소원으로 하여 7주간 배양하였다. 실험 결과, 토착균 군집이 존재하는 IND와 MIX에서 BAC에 비하여 높은 함량의 비소가 용출되었으며, pH가 높은 G10 토양에서 F1과 G7 토양에 비해 비소 용출량이 월등히 높았다. G10 토양의 경우, 다른 토양과 달리 용출된 비소 중 As(III) 함량의 비율이 낮았다. 이러한 결과는 토양에 따라 상이하게 나타나는 미생물 군집의 차이에 기인할 수도 있다. IND와 MIX는 7주차에 이르러 미생물의 다양성이 크게 감소하였으며 실험 조건에 적응한 Eubacteriales 및 Bacillales 등의 우점목이 번성하였다. F1 토양의 7주차 MIX에서는 Bacteroidales, G7 토양의 7주차 IND와 MIX에서는 Rummelibaciilus가 번성하였다. G10 토양의 IND와 MIX에서는 Enterobacterales가 우점목 중 하나를 차지하였다. 현재로서는 미생물 군집의 변화가 비소의 지구화학적 거동에 어떠한 메커니즘으로 영향을 미치는지에 관한 정보가 부족하나, 이러한 결과는 토양 내 마이크로바이옴이 비소의 용출을 조절하는 요인 중 하나로 기능할 수 있음을 나타낸다.

• Journal of Microbiology and Biotechnology
• /
• 제17권1호
• /
• pp.67-73
• /
• 2007

The present study compared the microbial diversity and activity during the application of various bioremediation processes to crude oil-contaminated soil. Five different treatments, including natural attenuation (NA), biostimulation (BS), biosurfactant addition (BE), bioaugmentation (BA), and a combined treatment (CT) of biostimulation, biosurfactant addition, and bioaugmentation, were used to analyze the degradation rate and microbial communities. After 120 days, the level of remaining hydrocarbons after all the treatments was similar, however, the highest rate (k) of total petroleum hydrocarbon (TPH) degradation was observed with the CT treatment (P<0.05). The total bacterial counts increased during the first 2 weeks with all the treatments, and then remained stable. The bacterial communities and alkane monooxygenase gene fragment, alkB, were compared by denaturing gradient gel electrophoresis (DGGE). The DGGE analyses of the BA and CT treatments, which included Nocardia sp. H17-1, revealed a simple dominant population structure, compared with the other treatments. The Shannon-Weaver diversity index (H') and Simpson dominance index (D), calculated from the DGGE profiles using 16S rDNA, showed considerable qualitative differences in the community structure before and after the bioremediation treatment as well as between treatment conditions.

• 한국토양비료학회지
• /
• 제46권3호
• /
• pp.173-181
• /
• 2013

Livestock wastes are considered as major environmental pollutants because they contain high concentration of organic materials. In 2001, The Environmental Department reported that stock farmers were increasing as 5.1%/year, which resulted in a gradual increase in livestock wastes generation. The direct disposal of livestock wastes create several environmental problems. Thus, several countries banned the disposal of livestock wastes in environment including aquatic systems. Recently, aeration-based liquid fertilization was considered as potential way for the disposal of livestock wastes. In this study, next generation sequencing (NGS) analysis was used to understand the microbial community changes during liquid fertilization of livestock wastes. Microbial community was compared with liquid fertilizer physicochemical analysis such as $BOD_5$, $COD_{Mn}$ pH, N (Nitrogen), P (Phosphorus), K (Potassium) etc. The physicochemical parameters and bacterial community results pave the way for producing effective livestock-based fertilizer. By comparing the physical characteristics of the manure with microbial community changes, it is possible to optimize the conditions for producing effective fertilizer.

• 미생물학회지
• /
• 제52권1호
• /
• pp.59-64
• /
• 2016

본 연구에서는 차세대 염기서열분석(pyrosequencing) 기술을 이용해 조릿대(Sasa borealis) 대나무림의 낙엽층과 근권 토양 내 주요 군집인 방선균군집의 계통학적 특성을 분석하여 방선균 유전자원 다양성 확보를 위한 기반 연구를 수행하고자 하였다. 낙엽층 시료 내 세균군집은 2,588 OTUs, 다양성 지수 7.55로 나타났으며, 근권토양 시료의 경우 2,868 OTUs, 다양성 지수 8.15로 다양한 세균군집이 균등하게 분포하고 있는 것으로 확인되었다. 대나무림 토양시료 내 세균군집은 총 35개의 문으로 구성되었으며, Proteobacteria (51-60%), Bacteroidetes (16-20%), Acidobacteria (4-16%) 그리고 Actinobacteria (4-14%) 계통군이 주요 세균군집으로 확인되었다. 특히, Actinobacteria은 총 6목 35과 121속의 다양한 방선균이 분포하였으며, 전체 방선균군집의 83%가 Actinomycetales 목으로 확인되었다. 이들 Actinomycetales 목은 28개 과로 구성되었으며, Micromonosporaceae, Pseudonocardiaceae 그리고 Streptomycetaceae는 조릿대 대나무림의 낙엽층과 근권토양에서 풍부도가 가장 높고 변이가 적은 대표 방선균군집으로 확인되었다.