• 한국토양환경학회지
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• 제4권3호
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• pp.95-104
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• 1999

소수성 오염물질인 원유성분의 분해메카니즘을 규명하기 위하여 원유중 알칸성분의 동시분해능을 지닌 Acinetobacter sp. 를 단리하여 액체/고체알칸, 서로다른 고체알칸을 단일 또는 복합기질로 하여 비교분해연구를 행하였다. 또한 비분해성 유기액상성분인 pristane을 원유매체, 고체알칸인 heneicosane을 유효기질로 하는 실험계를 확립하여 원유성분의 분해모델로서 연구를 행하였다. 본 연구에 이용된 Acinetobacter sp. 는 기질의 물리적 상태가 다른 액체/고체 성분의 분해특성에 차이를 보이지 않고 소수성기질의 표면에 직접접촉하여 분해할수 있음을 시사하였으며, 서로 다른 고체알칸의 단일 또는 복합 분해연구와 탄화수소에 대한 미생물의 부착성 결과가 이를 믿바침하였다. 또한 고체성분이 원유중에서는 유기상내에 용존상태로 존재함에 착안한 heneicosane/pristane계의 연구결과 원유매체는 미생물로의 유효기질 전달을 억제함을 밝혔으며, 단일성분으로 존재할때에 비하여 분해가 일어나기 위한 미생물과의 접촉면적을 감소시키는 유효기질의 비표면적 저하가 주요 원인임을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권8호
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• pp.1241-1245
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• 1999

Nine two-year old sheep fitted with rumen and duodenum cannulas were used to study the effect of controlling protozoa flora on the degradation and utilization of dietary fibre and protein in the rumen and on nitrogenous flow to the duodenum. There were three groups in this experiment: defaunation (DF); partial defaunation (PDF); faunation (F) as control. Results showed that: 1,There were no differences between treatments in dietary DM degradation in the rumen, but defaunation and partial defaunation increased the quantity of nitrogenous material in the rumen and the flow of N to duodenum. 2, partial defaunation and defaunation improved the degradabilities of dietary NDF, ADF and HC, but there were no differences between the defaunated and partially defaunated groups. 3, Partial defaunation decreased the degradability of dietary protein in the rumen. There was no difference between defaunated and faunated groups. 4, Defaunation and partial defaunation increased the quantity of total N (TN) and microbial N (MCN) in the rumen and the amounts entering the duodenum. The protozoa N (PN) flow in the faunated group was higher than that in the partially defaunated group, and the amino acid pattern in the digesta at the proximal duodenum in the defaunated group was closer to the ideal amino acid pattern. 5, There were differences in the mole percent of acetic, propionic, total-VFAs and the non-glucogenic to glucogenic VFAs ratio (NGR) value in the rumen fluids. The order was as follows: mole percent of acetate: F>PDF>DF; mole percent of propionate: DF>PDF>F; total-VFAs: PDF>F>DF; NGR: F>PDF>DF.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.81-91
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• 2011

Current fuel ethanol research and development deals with process engineering trends for improving biotechnological production of ethanol. Recently, a large amount of studies regarding the utilization of lignocellulosic biomass as a good feedstock for producing fuel ethanol is being carried out worldwide. The plant biomass is mainly composed of cellulose, hemicellulose and lignin. The main challenge in the conversion of biomass into ethanol is the complex, rigid and harsh structures which require efficient process and cost effective to break down. The isolation of microorganisms is one of the means for obtaining enzymes with properties suitable for industrial applications. For these reasons, crude cultures containing cellulosic biomass degrading microorganisms were isolated from rice field soil, cow farm soil and rotten rice straw from cow farm. Carboxymethyl cellulose (CMC), xylan and Avicel (microcrystalline cellulose) degradation zone of clearance on agar platefrom rice field soil resulted approximately at 25 mm, 24 mm and 22 mm respectively. As for cow farm soil, CMC, xylan and Avicel degradation clearancezone on agar plate resulted around at 24mm, 23mm and 21 mm respectively. Rotten rice straw from cow farm also resulted for CMC, xylan and Avicel degradation zone almost at 24 mm, 23 mm and 22 mm respectively. The objective of this study is to isolatebiomass degrading microbial strains having good efficiency in cellulose hydrolysis and observed the effects of different substrates (CMC, xylan and Avicel) on the production of cellulase enzymes (endo-glucanase, exo-glucanase, cellobiase, xylanase and avicelase) for producing low cost biofuel from cellulosic materials.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.812-815
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• 2005

This study was conducted to see the influence of additives and fermentation periods on Mott grass silage (MGS) characteristics, its chemical composition and to compare the digestion kinetics of Mott grass (MG) and MGS in Nili buffaloes. Mott grass chopped with a locally manufactured chopper was ensiled using two additives, cane molasses and crushed corn grains each at 2, 4 and 6% of forage DM for 30 and 40 days in laboratory silos. The pH, lactic acid concentration, dry matter (DM), crude protein and fiber fractions of MGS were not affected by the type or level of additive and fermentation periods. The non-significant pH lactic acid concentration, and chemical composition of MGS indicated that the both molasses and crushed corn were utilized at similar rate for the growth of lactic acid bacteria and production of organic acids. The MG ensiled with molasses at 2% of fodder DM for 30 days was screened out for in situ digestion kinetics in Nili buffaloes. Ruminal DM and neutral detergent fiber (NDF) degradabilities of MGS were significantly (p<0.05) higher than that of MG. The DM and NDF rate of degradation, lag time and extent of degradation was nonsignificant between MGS and MG. The higher ruminal degradation of DM and NDF of MGS than MG was probably a reflection of fermentation of MG during ensilation that improved its degradability by improving the availability of easily degradable structural polysaccharides to ruminal microbial population. The results in the present study have indicated that MG ensiled with either 2% molasses or 2% crushed corn for 30 days has better nutritive value for buffalo.

• Asian-Australasian Journal of Animal Sciences
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• 제6권1호
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• pp.5-11
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• 1993

First crop of alfalfa (Medicago sativa L.) was harvested, wilted and ensiled with or without NaOH or $NH_3$, and fed to three rumen fistulated goats in a $3{\times}3$ Latin-square design. Each alkali treatment (2.44% of alfalfa dry matter) was made by spraying its solution prior to ensiling. Silage pH, $NH_3-N$ and butyric acid concentration were increased with each alkali addition, and NaOH-treated silage showed the lowest chemical quality. Compared with untreated silage, digestibilities of organic matter, ADF and cellulose were depressed by both alkali treatments, and the reductions in NaOH-treated silage were significant. Crude protein digestibility was also significantly decreased in NaOH-treated silage, but the goats receiving the silage excreted less nitrogen in urine than those on the other two silages. Nitrogen retention of goats was not different among the treatments. Ruminal solubility and potential degradability of dry matter and nitrogen determined with the in situ bag technique were reduced, and rate of degradation of the two components were increased by the NaOH treatment. Addition of $NH_3$ provided ruminal soluble nitrogen to the silage, but the rate of degradation was similar to that of untreated silage. These results suggest that NaOH treatment would denature the protein and reduce the susceptibility to microbial degradation in the rumen, while no positive effect of alkali treatment on fiber digestion and nitrogen utilization was observed in this study.

• Applied Biological Chemistry
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• 제26권1호
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• pp.53-57
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• 1983

이종(二種)의 토양(土壤)을 가지고 논과 유사한 상태(狀態)로 만들어 butachlor를 일정기간(一定其間) 배양시(培養時) 모든 경우 주분해산물(主分解産物)로 2,6-diethyl-N-(butoxymethyl) acetanilide와 신분해산물(新分解産物) C를, 그리고 경우에 따라서는 비교적(比較的) 소량(少量)의 신분해산물(新分解産物) 8-ethyl-2-hydroxy-N-(butoxymethyl) 3,4-dihydroguinoline을 생성(生成)하였다. 토양미산물(土壤微産物)의 작용(作用)으로 추측(推測)되는 이 분해(分解)는 어느 정도 배양기간에 비 해하여 진행(進行)되었다. 전번 연구의 혐기적 배양시에는 2,6-diethyl-N-(butoxymethyl) acetanilide가 주분해산물(主分解産物)인 반면 이번 경우에는 m/z a91의 물질(物質)이 주분해산물(主分解産物)이었다. 그리고 Mass Spectrum의 Fragmentation Pattern에 의(依)하여 이들 신분해산물(新分解産物)의 화학구조(化學構造)를 구명(究明)하고 가능(可能)한 생성경로(生成經路)를 추정(推定)하였다.

• Journal of the Korean Wood Science and Technology
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• 제31권4호
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• pp.71-80
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• 2003

목재의 주성분 중 가장 분해가 어려운 리그닌을 분해하는 균주를 선발하기 위해 산림지역에서 채취한 부후목과 자실체로부터 균을 분리하였다. 리그닌 분해능은 활엽수보다 미생물 분해가 어렵다고 알려진 침엽수인 소나무재에 미생물을 처리하여 Klason 리그닌 정량을 통해 조사하였다. 또한 선발균에 의한 소나무재의 분해과정과 부후정도를 주사전자현미경(Scanning Electron Microscope ; SEM)을 이용해 조사하였다. 선발 균주 중 CJ-6에서 소나무 리그닌의 분해율이 49.48%로 가장 높았으며, 이것은 리그닌 분해 우수 균주로 알려진 Trametes versicolor의 40.58%와 비교해 보았을 때 리그닌 분해력이 더 우수하였다. 균주들 중 리그닌 분해력이 좋게 나타난 2개의 균주를 대상으로 부후에 의한 목재조직의 변화를 관찰하였는데 두 균주의 부후형이 비슷한 경향을 나타내었다. 부후 20일 경과에서는 균사의 침입은 있었으나 아직 목재는 건전한 상태를 유지하고 있었으며, 60일 간의 부후에서는 부후가 어느 정도 진행되어 가도관 벽과 방사조직의 세포벽의 일부가 분해되어 있음을 알 수 있었다. 100일간 부후가 진행된 경우에는 부후가 상당히 진행되어 가도관 세포벽 안쪽이 분해가 많이 진행되어 있었으며, 방사조직의 세포벽이 많이 분해되어 있어 세포간의 구별이 어려웠다.

• 유기물자원화
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• 제14권3호
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• pp.117-125
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• 2006

원유에 오염된 토양으로부터 톨루엔을 분해할 수 있는 미생물을 분리하였으며 동정결과 Pseudomonas fluorescence였다. 이 미생물을 생물학적 톨루엔 처리공정에 사용하기 위해 온도, 톨루엔 농도, pH, 질소원 등의 환경영향이 분해에 미치는 영향에 대해서 연구를 하였다. 이 미생물의 최적 분해 온도는 $30^{\circ}C$였으며 이 때 최대 비성장속도와 최대 비소모속도는 각각 $0.76hr^{-1}$와 $0.36hr^{-1}$이었다. $10^{\circ}C$ 와 $40^{\circ}C$에서는 톨루엔을 분해하지 못하였으나 $30^{\circ}C$에 적응한 미생물은 $10^{\circ}C$에서 17시간 만에 100mg/L의 톨루엔을 완전히 분해하였고 $40^{\circ}C$ 에서는 30시간 동안 80% 정도 분해할 수 있었다. 본 미생물은 200mg/L 이상의 톨루엔은 분해할 수 없었으나 20mg/L의 낮은 농도의 톨루엔에 적응을 시킴으로써 300mg/L의 톨루엔까지 분해할 수 있었다. pH는 5.5~9.0 범위에서 분해 속도에 별다른 영향을 미치지 않는 것으로 나타났다. 암모늄 (${NH_4}^+$) 대신 질산염(${NO_3}^-$)을 사용했을 때 적응기가 2~10시간 정도 길어졌고 미생물 수율이 45% 정도 감소하였다. 그러나 적응기가 지난 후의 톨루엔 분해속도에서는 별 차이를 보이지 않았다. 본 연구에서 얻은 결과들은 향후 바이오필터 등의 생물학적 톨루엔 처리공정 개발에 유용하게 사용될 것으로 기대된다.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E2호
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• pp.79-84
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• 2002

The objective of this study was to investigate the biodegradation of ethylene in an activated carbon biofilter inoculated with immobilized microbial consortium. The biofilter performance was monitored in terms of ethylene removal efficiency and carbon dioxide production. The biofilter was capable of achieving ethylene removal efficiency as much as 100% at a residence time of 14 min and an inlet concentration of 290 ppm. Under the same conditions, carbon dioxide with a concentration of up to 546 ppm was produced. Its was found that carbon dioxide was produced at a rate of 87 mg day$\^$-1/, which corresponded to a volume of 0.05 L day$\^$-1/. During operation with an inlet ethylene of 290 ppm, the maximum elimination capacity of the biofilter was 34 g of C$_2$H$_4$m$\^$-3/ day$\^$-1/. The biofilter could provide an attractive treatment technology for removing ethylene, an extremely volatile and slowly adsorbed compound.