• Asian-Australasian Journal of Animal Sciences
• /
• 제13권10호
• /
• pp.1399-1406
• /
• 2000

A continuous culture study was conducted to determine the impact of ruminal degradable soy protein (S-RDP) level and dilution rate (D) on growth of ruminal non-structural carbohydrate-fermenting microbes. Corn starch, urea and isolated soy protein (ISP) were used to formulate three diets with S-RDP levels of 0, 35 and 70% of total dietary CP. Two Ds were 0.03 and $0.06h^{-1}$ of the fermenter volume in a single-effluent continuous culture system. As S-RDP levels increased, digestibilities of dietary dry matter (DM), organic matter (OM) and crude protein (CP) linearly (p=0.001) decreased, whereas digestion of dietary starch linearly (p=0.001) increased. Increasing D from 0.03 to $0.06h^{-1}$ resulted in decreased digestibilities of dietary DM and OM, but had no effect on digestibilities of dietary starch (p=0.77) and CP (p=0.103). Fermenter pH, the concentration of volatile fatty acids (VFA) and daily VFA production were unaffected (p=0.159-0.517) by S-RDP levels. Molar percentages of acetate, propionate and butyrate were greatly affected by S-RDP levels (p=0.016-0.091), but unaffected by D (p=0.331-0.442). With increasing S-RDP levels and D, daily bacterial counts, daily microbial N production (DMNP) and microbial efficiency (MOEFF; grams of microbial N produced per kilogram of OM truly digested) were enhanced (p=0.001). The increased microbial efficiency with increasing S-RDP levels is probably the result of peptides or amino acids that served as a stimulus for optimal protein synthesis. The quantity of ruminal degradable protein from soy proteins required for optimum protein synthesis of non-structural carbohydrate-fermenting microbes appears to be equivalent to 9.5% of dietary fermented OM.

• Journal of Microbiology and Biotechnology
• /
• 제19권7호
• /
• pp.651-657
• /
• 2009

Shifts in the activity and diversity of microbes involved in aliphatic and aromatic hydrocarbon degradation in contaminated soil were investigated. Subsurface soil was collected from a gas station that had been abandoned since 1995 owing to ground subsidence. The total petroleum hydrocarbon content of the sample was approximately 2,100 mg/kg, and that of the soil below a gas pump was over 23,000 mg/kg. Enrichment cultures were grown in mineral medium that contained hexadecane (H) or naphthalene (N) at a concentration of 200 mg/l. In the Henrichment culture, a real-time PCR assay revealed that the 16S rRNA gene copy number increased from $1.2{\times}10^5$to $8.6{\times}10^6$with no lag phase, representing an approximately 70-fold increase. In the N-enrichment culture, the 16S rRNA copy number increased about 13-fold after 48 h, from $6.3{\times}10^4$to $8.3{\times}10^5$. Microbial communities in the enrichment cultures were studied by denaturing gradient gel electrophoresis and by analysis of 16S rRNA gene libraries. Before the addition of hydrocarbons, the gas station soil contained primarily Alpha- and Gammaproteobacteria. During growth in the H-enrichment culture, the contribution of Bacteriodetes to the microbial community increased significantly. On the other hand, during N-enrichment, the Betaproteobacteria population increased conspicuously. These results suggest that specific phylotypes of bacteria were associated with the degradation of each hydrocarbon.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제5권3호
• /
• pp.207-210
• /
• 2000

When endothelial cells isolated isolated from human umbilical venis were cultred for 6dary using 96-well microplates, the final cell density in each was fiund not to be the same although the medium composition of each well was exactly the same. Cell growth in the wells located at the periphery of a microplate was low, while that in the central area of the plate was high. A possible cause for different rate of growth was proposed as the uneven concentration of oxygen in the culture medium of each well.

• 식품과학과 산업
• /
• 제50권1호
• /
• pp.2-10
• /
• 2017

Human have eaten various traditional fermented foods for a numbers of million years for health benefit as well as survival. The beneficial effects of fermented foods have been resulted from complex microbial communications within the fermented foods. Therefore, the holistic approaches for individual identification and complete microbial profiling involved in their communications have been of interest to food microbiology fields. Microbiome is the ecological community of microorganisms that literally share our environments including foods as well as human body. However, due to the limitation of culture-dependent methods such as simple isolations of just culturable microorganisms, the culture-independent methods have been consistently developed, resulting in new light on the diverse non-culturable and hitherto unknown microorganisms, and even microbial communities in the fermented foods. For the culture-independent approaches, the food microbiome has been deciphered by employing various molecular analysis tools such as fluorescence in situ hybridization, quantitative PCR, and denaturing gradient gel-electrophoresis. More recently, next-generation-sequencing (NGS) platform-based microbiome analysis has been of interest, because NGS is a powerful analytical tool capable of resolving the microbiome in respect to community structures, dynamics, and activities. In this overview, the development status of analysis tools for the fermented food microbiome is covered and research trend for NGS-based food microbiome analysis is also discussed.

• Bulletin of the Korean Chemical Society
• /
• 제25권6호
• /
• pp.813-818
• /
• 2004

A systematic study of microbial fuel cells comprised of thermophilic Bacillus licheniformis and Bacillus thermoglucosidasius has been carried out under various operating conditions. Substantial amount of electricity was generated when a redox mediator was used. Being affected by operation temperature, the maximum efficiency was obtained at 50$^{\circ}C$ with an open circuit voltage of ca. 0.7 V. While a small change around the optimum temperature did not make much effect on the cell performance, the rapid decrease in performance was observed above 70$^{\circ}C$. It was noticeable that fuel cell efficiency and discharge pattern strongly depended on the kind of carbon sources used in the initial culture medium. In the case of B. thermoglucosidasius, glucose alone was utilized constitutively as a substrate in the microbial fuel cell irrespective of used carbons sources. When B. licheniformis was cultivated with lactose as a carbon source, best charging characteristics were recorded. Trehalose, in particular, showed 41.2% coulombic efficiency when B. thermoglucosidasius was cultured in a starch-containing medium. Relatively good repetitive operation was possible with B. thermoglucosidasius cells up to 12 cycles using glucose as a carbon source, when they were cultured with lactose as an initial carbon source. This study demonstrates that highly efficient thermophilic microbial fuel cells can be constructed by a pertinent modulation of the operating conditions and by carefully selecting carbon sources used in the initial culture medium.

• 대한예방한의학회지
• /
• 제15권3호
• /
• pp.153-162
• /
• 2011

1. 서울, 경기소재 한의원에서 환약 10종과 경기소재 약국1곳에서 판매되는 한방환약 10종, 총 20종의 환약에 대해 미생물검출연구를 하였다. 2. 총세균수는 한의원환약, 약국환약에서 모두 WHO기준(1.0${\times}$107) 이내로 검출되었다. 3. 총진균수는 한의원환약, 약국환약의 각각 2종류, 1개제품에서 WHO기준(1.0${\times}$104)을 초과 하였다. 4. 배양 비의존적 방법을 이용하여 환약에 분포하는 Bacteria를 동정한 결과, 대부분의 박테리아는 토양에 존재하는 Firmicutes문, Proteobacteria문의 두 종류에 속하였다. 5. 환약의 안전성을 제고하기 위해, 생산, 가공, 유통, 보관 등 각 단계에서의 추가적인 미생물검출연구가 필요하다.

• Journal of Microbiology and Biotechnology
• /
• 제27권12호
• /
• pp.2089-2093
• /
• 2017

The past decades have been a golden era during which great tasks were accomplished in the field of microbiology, including food microbiology. In the past, culture-dependent methods have been the primary choice to investigate bacterial diversity. However, using culturein-dependent high-throughput sequencing of 16S rRNA genes has greatly facilitated studies exploring the microbial compositions and dynamics associated with health and diseases. These culture-independent DNA-based studies generate large-scale data sets that describe the microbial composition of a certain niche. Consequently, understanding microbial diversity becomes of greater importance when investigating the composition, function, and dynamics of the microbiota associated with health and diseases. Even though there is no general agreement on which diversity index is the best to use, diversity indices have been used to compare the diversity among samples and between treatments with controls. Tools such as the Shannon-Weaver index and Simpson index can be used to describe population diversity in samples. The purpose of this review is to explain the principles of diversity indices, such as Shannon-Weaver and Simpson, to aid general microbiologists in better understanding bacterial communities. In this review, important questions concerning microbial diversity are addressed. Information from this review should facilitate evidence-based strategies to explore microbial communities.

• Journal of Applied Biological Chemistry
• /
• 제57권3호
• /
• pp.197-203
• /
• 2014

Various parameters such as solvent selection, concentration, solid/liquid ratio, soaking time, temperature, stationary, shaking conditions, and repeated extractions were investigated in order to determine the optimum extraction conditions of ${\beta}$-glucosidase from bagasse fermented by mixed culture of Aspergillus niger NRC 7A and Aspergillus oryzae NRRL 447. Among various solvents tested, non ionic detergents gave the best results than the inorganic or organic salt solutions and distilled water. The optimum conditions for extraction of ${\beta}$-glucosidase were 30 min soaking time at $40^{\circ}C$ under shaking condition at 150 rpm, with solid/liquid ratio 1:15 (w/v), which yielded $2882.74{\pm}95.52U/g$ fermented culture (g fc) of enzyme activity. With repeated washes under the above optimum conditions, the results showed that enzyme extracted in the $1^{st}$ and $2^{nd}$ washes represents about 90% of the total activity.

• Journal of Life Science
• /
• 제11권1호
• /
• pp.11-13
• /
• 2001

Several culture conditions affecting cellulose production by a newly isolated Acetobacter sp. A9 were examined by cultivating cells under shaking cultures. The inoculum size in the range of 1-10% (v/v) did not influence cellulose production. Maximum cellulose production was obtained with 200 rpm of agitation speed. The cells grown in the 75 ml of medium in a 250-ml conical flask produced the highest level of cellulose. The strain was able to produce cellulose at 25-3$0^{\circ}C$ with a maximum at 3$0^{\circ}C$. Cellulose production occurred at pH 4.5-7.5 with a maximum at pH6.5.

• 한국미생물·생명공학회지
• /
• 제21권2호
• /
• pp.144-149
• /
• 1993

We have identified a T cell-activating material in the culture supernatant of Streptomyces species. The factor in microbial culture supernatant (MCS) induced thymocyte proliferation in a does dependent fashion and it could be detected by immunoblot analysis using anti-interleukin-1(IL-1) antibody. The factor in MCS was slightly larger(about 21 kd) in its molecular weight than IL-1 on SDS-PAGE. When 125I-MCS was covalently coupled with homo-bifunctional cross-linking agent, disuccinimidyl-propionate to IL-1 receptor(IL-1R) on mouse thymoma cell(EL-4) and immunoprecipitated with anti-IL-1R antibody the molecular weight of this complex of 110 kd was observed.