• 한국미생물·생명공학회지
• /
• 제19권5호
• /
• pp.487-490
• /
• 1991

효모 재순환계에 의한 당밀의 연속발효를 하였다. 단계적으로 YPD배지 농도를 10g/l에서 183.5g/l로 증가시킨 후 최종 발효배지는 당밀로 하였다. 최고의 효모농도는 25g/l였고, 운전중 평균 효모농도는 23.5g/l으로 종래 회분식보다 3.4배 높았다. 최적 발효조건은 180g/l의 당밀배지를 공급하였을 때 교반속도 500rpm, 희석을 0.037$h^{-1}$였다. 이 조건을 645시간 연속 운전하였으며 최고 알코올 생산성은 4.9g$l\cdot h$로서 이때의 희석율은 0.091$h^{-1}$, 알코올 농도는 53.9g/l이었다.

• 한국연초학회지
• /
• 제30권1호
• /
• pp.14-24
• /
• 2008

The objective of this study was to determine the effect of smoking conditions on the in vitro toxicological activity of mainstream smoke. The 2R4F reference cigarette was machine-smoked by International Organization for Standardization(ISO) and Canadian Intense(CI) conditions. Smoke was analysed for chemical composition and in vitro toxicity. The cytotoxic potencies of both the total particulate matter(TPM), which were collected in Cambridge filter pad, and gas/vapor phase(GVP), which was bubbled through in phosphate-buffer saline in a gas-washing bottle, were assessed neutral red up take assay with chinese hamster ovary(CHO) cells. The assessment for genotoxicity of TPMs generated under ISO and CI conditions was determined using Salmonella mutagenicity assay and in vitro micronucleus assay. When calculated on an equal TPM basis, in vitro toxicity of TPM obtained under CI condition was decreased compared to TPM generated under ISO condition. The results of chemical composition analyses revealed that the lower toxicological activity under CI condition than that of ISO condition could be explained by the decreased in the contents of phenols, N-nitrosoamines and aromatic amines of TPM on an equal TPM basis.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2008년도 추계학술대회 논문집
• /
• pp.431-432
• /
• 2008

• Journal of applied mathematics & informatics
• /
• 제26권1_2호
• /
• pp.275-282
• /
• 2008

Our aim in this paper is to investigate the global attractivity of the recursive sequence $x_{n+1}$ = $\frac{\alpha-{\beta}x_{n-1}}{\gamma+g(x_n)}$ under specified conditions. We show that the positive (or zero for $\alpha$ = 0) equilibrium point of the equation is a global attractor with a basin that depends on certain conditions posed on the coefficients and the function g(x).

• Journal of Applied Biological Chemistry
• /
• 제58권1호
• /
• pp.25-29
• /
• 2015

The determination of the optimum conditions for the conversion of ergosterol to vitamin $D_2$ in shitake mushrooms (Lentinula edodes) was studied using response surface methodology (RSM). The effects of the three main variables ambient temperature ($20-40^{\circ}C$), exposure time (60-180 min), and irradiation intensity ($0.6-1.8W/m^2$) were investigated. According to the RSM ridge analysis, the optimum conditions were as follows: ambient temperature of $34.2^{\circ}C$, exposure time of 175.6 min, and irradiation intensity of $1.41W/m^2$. Under these optimum conditions, the maximum vitamin $D_2$ content of $117.93{\mu}g/g$ in shitake mushrooms was obtained, which agreed fairly well with the predicted value of $122.60{\mu}g/g$.

• Food Science and Biotechnology
• /
• 제14권2호
• /
• pp.190-195
• /
• 2005

The conditions for the extraction of effective substances from the stem of Opuntia ficus-indica were optimized by a response surface methodology. The total extract yield was maximized under the temperature of $97.77^{\circ}C$, at a time duration of 145.82 min and a water to sample ratio 16.59 mL/g. Moreover, the optimum conditions for the extraction of effective substances were as follows: $84.95^{\circ}C$, 156.50 min and a water/sample ratio of 7.46 mL/g for the phenolics content; and $97.11^{\circ}C$, 139.03 min and a water/sample ratio of 10.91 mL/g for the pectin content. The range of optimum extraction conditions in consideration of the physicochemical properties of the extracts were shown to be as $95-100^{\circ}C$ as the extraction temperature, 120-180 min as extraction time and a water to sample ratio of 5-18 mL/g.

• KSBB Journal
• /
• 제8권5호
• /
• pp.452-456
• /
• 1993

Pichia stipitis CBS 5776에 의한 xylose의 최적 알코올 발효조건에 대한 연구를 수행하였다. 최적 세포성장 및 최대 ethanol 생성은 초가 pH가 5.0인 100 g/l 의 xylose배지를 이용하여 $30^{\circ}C$에서 0.05VVM으로 통기하고 300rpm으로 교반하는 발효 조건에셔 얻을 수 있었다. 이러한 최적 발효조건 서의 최대 비성장속도와 최대 세포농도는 각각 $0.14hr^{-1}$와 $1.3\times109$ cells/ml이였다. 또한 최대 etha­n nol 농도는 72시간 발효시에 100 g/l 의 xylose 중 에셔 96%을 이용하여 40.2 g/l 을 얻었으며, 이때 의 단위부피당 ethanol 생산성은 0.56 g/l-hr이고 ethanol 수율은 0.42g-ethanol/g-xylose로서 이론수율의 82%였다.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.149-152
• /
• 2003

본 연구에서는 담자균류의 일종인 Tricholoma matsutake의 균사체 생육과 polysaccharide 생산을 최적화하기 위하여 5L jar fermentor에서 교반속도와 통기량의 영향을 검토하였다. 교반속도는 150 rpm에서 가장 좋은 결과를 보였으며, 균체량은 배양 10일째 21.87 g/L, polysaccharide는 교반속도는 300 rpm에서 배양 8일째 8.86 g/L 로 가장 높은 값을 나타내다. 통기량은 11일째 0.5 vvm에서 가장 좋은 균체량 20.85 g/L, polysaccharide는 1.5vvm에서 배양 11일째 8.83 g/L로 가장 높은 값을 나타내었다.

• BMB Reports
• /
• 제30권5호
• /
• pp.346-351
• /
• 1997

The maximum adsorption/desorption conditions and the adsorption mechanism of globular proteins to vaccine adjuvants were determined. The maximum adsorption ratio of protein to the $Al^{3+}$ content of aluminum oxyhydroxide and the optimal adsorption pH are 2:1 (${\mu}g:{\mu}g$) for bovine serum albumin (BSA) at pH 6.0 and 2.5:1 (${\mu}g:{\mu}g$) for immunoglobulin G (IgG) at pH 7.0, respectively. The maximum adsorption ratio onto aluminum phosphate gel was 1.5:1 (${\mu}g$ Protein:${\mu}g$ $Al^{3+}$) at pH 5.0 for both BSA and IgG. Adsorption of the native globular proteins, BSA and IgG, to aluminum oxyhydroxide and aluminum phosphate gel was reversible as a function of pH. Complete desorption of these proteins from aluminum phosphate gel was observed at alkaline pH, whereas only 80~90% removal from aluminum oxyhydroxide was achieved with alkaline pH and 50 mM phosphate buffer. We conclude that electrostatic and hydrogen bonding interactions between the native proteins and adjuvants are important binding mechanisms for adsorption, and that the surface charge of the protein and the colloid components control the maximum adsorption conditions.

• 대한수학회보
• /
• 제58권1호
• /
• pp.31-46
• /
• 2021

Let a and b be positive integers, and let V (G), ��(G), and ��2(G) be the vertex set of a graph G, the minimum degree of G, and the minimum degree sum of two non-adjacent vertices in V (G), respectively. An even [a, b]-factor of a graph G is a spanning subgraph H such that for every vertex v ∈ V (G), dH(v) is even and a ≤ dH(v) ≤ b, where dH(v) is the degree of v in H. Matsuda conjectured that if G is an n-vertex 2-edge-connected graph such that $n{\geq}2a+b+{\frac{a^2-3a}{b}}-2$, ��(G) ≥ a, and ${\sigma}_2(G){\geq}{\frac{2an}{a+b}}$, then G has an even [a, b]-factor. In this paper, we provide counterexamples, which are highly connected. Furthermore, we give sharp sufficient conditions for a graph to have an even [a, b]-factor. For even an, we conjecture a lower bound for the largest eigenvalue in an n-vertex graph to have an [a, b]-factor.