• 한국미생물·생명공학회지
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• 제5권1호
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• pp.18-23
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• 1977

섬유소자화세균 Cellulomonas flavigena KIST 321로 섬유소 단세포 단백을 생산하기 위하여 우리주변에서 제기되고 있는 각종 섬유소폐기물을 수집하여 기질로서의 사용 가능성을 검토하였는 바 그 결과를 요약하면 다음과 같다. 1. 당유를 유일한 탄소원으로 하였을 때 cellulose와 rylose에서 균체량이 가장 많았다. 2. 폐지유와 폐의유를 기질로 하였을 때 알카리 전처리를 함으로써 알카리 전처리하지 않았을 때보다 균체량이 많았으며, 폐신문지와 같은 인쇄물에서는 균체량이 적었다. 3. 짚류(straws)를 기질로 하였을 때는 대체로 균체수율이 높았으며, 볏짚, 채종대, 피를 기질로 하였을 때 균체량이 많았다. 4. 목재유의 톱밥에서는 균체량이 적었으나 잎류(leaves)에서는 비교적 많았다. 5. 기질의 종류에 따라 전처리시 NaOH농도를 다르게 하여 균체생산량을 조사하였다. NaOH 농도는 기질의 종류에 따라 최적농도가 달랐으나 짚류(Straws)에서는 0.8∼1.0％ 일때가 좋았고, 잎류(leaves)에서는 0.4∼0.6％일때가 좋았다. 6. 각종기질을 알카리 처리후 세척하여 기질로 사용하였을 때 볏짚에서는 균체량이 감소하였으나 소나무 톱밥, 피나무 톱밥, 소나무잎, 폐신문지에서는 증가하였다.

• Journal of Ecology and Environment
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• 제29권6호
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• pp.565-572
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• 2006

팔당호에서 분포 면적과 빈도가 가장 큰 대형 수생 식물인 줄(Zizania latifolia), 갈대(Phragmites communis), 애기부들(Typha angustata) 3종의 잎과 줄기의 분해 실험을 낙엽 주머니 법(litter bag method)을 이용하여 2005년 7월에서 12월까지 실험하였다. 97일간의 실험 기간 동안 줄의 잎과 줄기는 각각 초기 건중량의 78.8%와 77.4%, 갈대의 잎과 줄기는 각각 67.5%와 43.6%, 애기부들의 잎과 줄기는 각각 55.3%와 61.9% 분해되었다. 식물체의 분해로 인한 중량 감소는 높은 질소(N) 함량과, 낮은 C/N을 보인 종과 식물체 부위에서 빠른 분해율을 나타내는 뚜렷한 상관이 있었다. 반면에 리그닌(lignin)의 함량이 높거나, lignin/N, cellulose/N이 높은 식물 종과 부위에서는 그 분해율이 늦은 것으로 나타났다. 수온과 수중 인(P)의 함량 변화와 낙엽 분해율 사이에는 양의 상관을 보였으나, $NO_3^-$-N 함량과는 음의 상관을 보였다. 더욱이 낙엽주머니의 망목의 크기를 달리한 각 낙엽주머니에서의 분해율은 차이를 나타내지 않아 이들 식물체의 분해는 대부분 갉아먹는 수생미소절지동물에 의하여 진행되는 것이 아니라 세균이나 곰팡이 등과 같은 미생물의 작용에 의하여 분해되고 있는 것으로 보이며, 특히 수중의 질소와 인(P)의 함량은 수온의 변화와 함께 이들 미생물의 소장에 영향을 주는 주요 환경요소로서 수중 식물체의 분해에 영향을 미치는 것으로 여겨진다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권7호
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• pp.957-966
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• 2017

Objective: To understand the dynamic structure, function, and influence on nutrient metabolism in hosts, it was crucial to assess the genetic potential of gut microbial community in yaks of different ages. Methods: The denaturing gradient gel electrophoresis (DGGE) profiles and Illumina-based metagenomic sequencing on colon contents of 15 semi-domestic yaks were investigated. Unweighted pairwise grouping method with mathematical averages (UPGMA) clustering and principal component analysis (PCA) were used to analyze the DGGE fingerprint. The Illumina sequences were assembled, predicted to genes and functionally annotated, and then classified by querying protein sequences of the genes against the Kyoto encyclopedia of genes and genomes (KEGG) database. Results: Metagenomic sequencing showed that more than 85% of ribosomal RNA (rRNA) gene sequences belonged to the phylum Firmicutes and Bacteroidetes, indicating that the family Ruminococcaceae (46.5%), Rikenellaceae (11.3%), Lachnospiraceae (10.0%), and Bacteroidaceae (6.3%) were dominant gut microbes. Over 50% of non-rRNA gene sequences represented the metabolic pathways of amino acids (14.4%), proteins (12.3%), sugars (11.9%), nucleotides (6.8%), lipids (1.7%), xenobiotics (1.4%), coenzymes, and vitamins (3.6%). Gene functional classification showed that most of enzyme-coding genes were related to cellulose digestion and amino acids metabolic pathways. Conclusion: Yaks' age had a substantial effect on gut microbial composition. Comparative metagenomics of gut microbiota in 0.5-, 1.5-, and 2.5-year-old yaks revealed that the abundance of the class Clostridia, Bacteroidia, and Lentisphaeria, as well as the phylum Firmicutes, Bacteroidetes, Lentisphaerae, Tenericutes, and Cyanobacteria, varied more greatly during yaks' growth, especially in young animals (0.5 and 1.5 years old). Gut microbes, including Bacteroides, Clostridium, and Lentisphaeria, make a contribution to the energy metabolism and synthesis of amino acid, which are essential to the normal growth of yaks.

• 한국미생물·생명공학회지
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• 제6권1호
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• pp.1-8
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• 1978

섬유소분해효소 생산균인 Trichoderma sp. KI 7-2의 cellulase생성을 위한 탄소원으로는 순수한 섬유소보다 볏짚 보리짚 분말을 사용하는 것이 좋았으며 1% 첨가에서 심부배양한 액을 유안농도 20~60%로 떨어뜨린 침전에서만 cellulase의 활성이 나타났다. 이 조효소의 작용최적온도는 5$0^{\circ}C$, 최적 pH는 4.2였으며, 열에 대한 안정성은 5$0^{\circ}C$에서 2시간까지 100% 활성을 유지하였고 pH에 대한 안정성은 pH4~6에서 안정하였지만 pH 4이하 및 pH 6.0 이상에서는 불안정하였다. 이러한 성질의 효소를 생산하는 균주로서 볏짚 발효시키는 몇 가지 방법을 아울러 검토하였다.

• 한국미생물·생명공학회지
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• 제9권2호
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• pp.65-69
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• 1981

농산폐자원을 이용하기 위한 방법으로써 Trichoderma sp. KI 7-2로 만든 koji와 내열성 효모를 사용하여 동시당화-발효와 당화액 발효를 비교하였다. 볏짚의 당화액에서는 15 mg/$m\ell$의 cellobiose가 존재하였으나 동일한 효소원을 사용한 동시당화-발효액에서는 존재하지 않았다. 효소당화법에서 는 cellulase enzyme system의 반응산물인 glucose가 cellobiose의 활성을 저해하므로 cellobiose 가 축적되었으나 동시당화-발효법에서 는 glucose가 ethanol로 발효되어 cellobiose의 축적이 없었다. Cutting mill 한 볏짚은 동시 당화-발효 과정에서는 ball mill 한 것과 같은 정도로 효과적으로 발효되었다. 이 결과로부터 cellylolytic enzyme system의 반응산물에 의한 저해 mechanism을 논의하였다. 또한 볏짚 당화시 약 10 mg/$m\ell$ 생산되는 xylose는 동시당화-발효에 아무런 영향을 미치지 않음을 확인하였다.

• 한국미생물·생명공학회지
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• 제4권3호
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• pp.105-110
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• 1976

곰팡이를 이용하여 섬유소분해효소를 생산할 목적으로 전국각처에서 수집한 102종의 시료로부터 총 221주의 곰팡이를 분리하였다. 이들 분리균주의 섬유소분해능을 여과 지붕괴법 ？ 액화법 및 cup method로서 1차 36균주를 선별하였고 1차 선별된 균주를 탄소원을 변경하여 배양한뒤 활성을 추정하여 2차로 15균주를 선별하였다. 15균주를 개선된 배지에서 배양한뒤 $C_1$, $C_{x}$ 및 filter paper-activity을 측정하여 최종적으로 $C_1$및 $C_{x}$ -Cellulase의 활성이 강한 균주인 Aspergillus sp. strain No. AS-9, Penicillium sp. strain No. KI-1-2 Trichoderma sp. strain No. KI-7-2, KI-7-5, 및 KI-4-IB을 선별하였다. 이상 최종적으로 선별된 균주중의 strain No. KI-4-1-1B 조효소액으로 ammonia 처리볏짚을 당화시킬 때 24시간 작용으로 26%가 당화되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권6호
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• pp.988-1001
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• 1999

The rumen ecosystem is increasingly being recognized as a promising source of superior polysaccharide-degrading enzymes. They contain a wide array of novel enzymes at the levels of specific activities of 1,184, 1,069, 119, 390, 327 and $946{\mu}mol$ Reducing sugar release/min/mg protein for endoglucanase, xylanase, polygalactouronase, amylase, glucanase and arabinase, respectively. These enzymes are mainly located in the surface of rumen microbes. However, glycoside-degrading enzymes (e.g. glucosidase, fucosidase, xylosidase and arabinofuranosidase, etc.) are mainly located in the rumen fluid, when detected enzyme activities according to the ruminal compartments (e.g. enzymes in whole rumen contents, feed-associated enzymes, microbial cell-associated enzymes, and enzymes in the rumen fluid). Ruminal fungi are the primary contributors to high production of novel enzymes; the bacteria and protozoa also have important functions, but less central roles. The enzyme activities of bacteria, protozoa and fungi were detected 32.26, 19.21 and 47.60 mol glucose release/min/mL mediem for cellulose; 42.56, 14.96 and 64.93 mmol xylose release/min/mL medium after 48h incubation, respectively. The polysachharide-degrading enzyme activity of ruminal anaerobic fungi (e.g. Neocallimastix patriciarum and Piromyces communis, etc.) was much higher approximately 3~6 times than that of aerobic fungi (e.g. Tricoderma reesei, T. viridae and Aspergillus oryzae, etc.) used widely in industrial process. Therefore, the rumen ecosystem could be a growing source of novel enzymes having a tremendous potential for industrial applications.

• 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.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.29-34
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• 2005

W/O/W (water-in-oil-in-water) type multiple emulsion was applied to improve the storage stability of an antagonistic microorganism, Burkholderia gladioli. Encapsulation of microorganism into a W/O/W emulsion was conducted by using a two-step emulsification method. W/O/W emulsion was prepared by the incorporation of B. gladioli into rapeseed oil and the addition of polyglycerin polyriconolate (PGPR) and castor oil polyoxyethylene (COG 25) as the primary and secondary emulsifier, respectively. Microcrystalline cellulose was used as an emulsion stabilizer. To evaluate the usefulness of W/O/W emulsion formulation as a microbial pesticide for controlling the bacterial wilt pathogen (Ralstonia solanacearum), the storage stability and antagonistic activity of emulsion formulation were tested in vitro. The storage stability test revealed that the viability of formulated cells in emulsion was higher than that of unformulated cells in culture broth. At $4^{\circ}C$, the viabilities of formulated cells and unformulated cells at the end of 20 weeks decreased to about 2 and 5 log cycles, respectively. At $37^{\circ}C$, the viability of formulated cells decreased to only 2 log cycles at the end of storage. On the other hand, the viable cells in culture broth were not detected after 13 weeks. In activity test, formulated cells in emulsion were more effective in inhibiting the growth of pathogen than unformulated cells in culture broth. Unformulated cells completely lost their antagonistic activity during storage under similar conditions. The W/O/W multiple emulsion formulation was shown to be useful as the novel liquid formulation for biological control.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.829-835
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• 2004

A fibrinolytic enzyme has been found in several bacteria isolated from fermented food. This study was carried out to investigate the purification and characteristics of the fibrinolytic enzyme produced by Bacillus subtilis KCK-7 originated from Chungkookjang. The fibrinolytic enzyme was purified to homogeneity from the culture supernatant using ammonium sulfate fractionation and chromatographies on DEAE-cellulose and on Sephadex G-100. The final specific activity of the purified enzyme increased 11.0-fold, and the protein amount in the purified enzyme was about 16% of that in the culture supernatant. The molecular weight of the purified enzyme was estimated to be about 45,000 by SDS-PAGE. The optimum pH and temperature for the enzyme activity were pH 7.0 and $60^{\circ}C$, respectively. The enzyme activity was relatively stable up to $60^{\circ}C$ over the pH range of 7.0-10.0. The fibrinolytic enzyme activity increased by $Ca^{2+}$ and $Cu^{2+}$, whereas it was inhibited by $Hg^{2+}$ and $Ba^{2+}$. In addition, it was severely inhibited by PMSF and DFT. It is suggested that the purified enzyme was a serine protease for the fibrinolysis. The purified enzyme could completely hydrolyze fibrin in vitro within 8 h. Hence, it is suggested that the purified enzyme can be put into practice as an effective thrombolytic agent.