• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.154-161
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• 2011

L. lactis sk071115 has been shown to grow more actively and generate lower levels of lactate in glucose-defined medium with nitrate than in medium with Mn(IV). By adding Mn(IV) to a L. lactis culture, lactate production was relatively reduced in combination with Mn(II) production, but cell mass production levels did not increase. Both cell-free extract and intact L. lactis cells reacted electrochemically with Mn(IV) but did not react with Mn(II) upon cyclic voltammetry using neutral red (NR) as an electron mediator. A modified graphite felt cathode with NR (NR-cathode) was employed to induce electrochemical reducing equivalence for bacterial metabolism. Cell-free L. lactis extract catalyzed the reduction of Mn(IV) to Mn(II) under both control and electrochemical reduction conditions; however, the levels of Mn(II) generated under electrochemical reduction conditions were approximately 4 times those generated under control conditions. The levels of Mn(II) generated by the catalysis of L. lactis immobilized in the NR-cathode (L-NR-cathode) under electrochemical reduction conditions were more than 4 times that generated under control conditions. Mn(II) production levels were increased by approximately 2.5 and 4.5 times by the addition of citrate to the reactant under control and electrochemical reduction conditions, respectively. The cumulative Mn(II) produced from manganese ore by catalysis of the L-NR-cathode for 30 days reached levels of approximately 3,800 and 16,000 mg/l under control and electrochemical reduction conditions, respectively. In conclusion, the electrochemical reduction reaction generated by the NR-cathode activated the biochemical reduction of Mn(IV) to Mn(II) by L. lactis.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.13-13
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• 2022

Recently, stable crop production is threatened by the effects of climate change. In particular, it is difficult to consistently maintain agricultural policies due to large price fluctuations depending on the difference in total domestic rice production from year to year. For stable rice production amid changes in the crop growing environment, development of varieties with improved disease resistance and abiotic stress stability is becoming more important. In here, drought and cold tolerant trait have been studied. First, for the development of drought tolerant varieties, we analyzed which agricultural traits are mainly affected by domestic drought conditions. As a result, it was observed that drought caused by the lack of water during transplanting season inhibits the development of the number of tiller and reduces the yield. 'Samgang' was selected as a useful genetic resource with strong drought tolerant and stable tiller number development even under drought conditions by phenotype screening. Three of drought tolerant QTLs were identified using doubled haploid (DH) population derived from a cross between Nacdong and Samgang, a drought sensitive and a tolerant, respectively. Among these QTLs, when qVDT2 and qVDTl1 were integrated, it was investigated that the tiller number development was relatively stable in the rainfed paddy field conditions. It is known that the high-yielding Tongil-type cultivars are severely affected by cold stress throughout the entire growth stage. In this study, we established conditions that can test the cold tolerance phenotype with alternate temperature to treat low temperatures in indoor growth conditions similar to those in field conditions at seedling stage. Three cold tolerant QTLs were explored using population derived from a cross between Hanareum2 (cold sensitive variety, Tongil-type) and Unkwang (cold tolerant variety, Japonica). Among these QTLs, qSCT12 showed strong cold tolerant phenotype, and when all of three QTLs were integrated, it was investigated that cold tolerant score was relatively similar to its donor parent, Unkwang, in our experimental conditions. We are performing that development of new variety with improved cold tolerant through the introduction of these QTLs.

• 한국농림기상학회지
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• 제4권3호
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• pp.141-150
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• 2002

본 연구는 경기도 가평과 관주 그리고 충청북도 영동에 조성된 잣나무 차대검정림을 대상으로 20년생까지의 연도별 구과 결실량에 미치는 미기후의 영향을 구명하기 위하여 수행되었다. 이를 위해 지역별ㆍ연도별 구과 결실량을 측정하여 분석하였으며, 지형기후학적 방법과 공간통계기법을 사용하여 차대검정림의 연도별 미기후 조건을 추정하여 구과 결실량에 미치는 영향을 분석하였다. 착과수 및 착과 본수를 조사한 결과 가평 지역은 9년생부터, 광주 지역은 10년 생부터 그리고 영동 지역은 이보다 훨씬 늦은 14년생부터 착과가 이루어지기 시작하여 지역별 편차가 있음을 알 수 있었다. 또한 지역별 총 착과수와 가계별 착과수에서도 큰 변이를 나타내고 있는 것으로 파악되었다. 구과 결실량과 지역별 미기후간의 상관분석 결과를 보면 가평 지역의 경우 개화수분 당년의 11월부터 익년 3월까지 5개월 간의 흐린 날수 합계가 높은 부의 상관을 나타내었으며, 광주 지역의 경우 개화수분 당년 6월부터 결실년도 8월까지 15개월 동안의 일조시수 합계가 유의성이 높은 부의 상관을 나타내었다. 한편, 영동 지역의 경우는 개화수분 당년의 11월부터 익년 3월까지의 평균기온 평균치와 개화수분 당년의 5월 평균기온 등에서 부의 상관관계를 인정할 수 있었다. 한편 구과 결실량을 기후지수에 의해 추정하기 위한 최적 회귀식은 지역별로 다양한 기후변수가 채택되었으나 비교적 설명력이 높아 여러 가지 환경 요인 중에서 미기후 조건이 구과 결실량에 영향을 미치는 것으로 판명되었다. 본 연구로부터 얻어진 결과는 잣나무 우량 종자생산에 적합한 입지선정에 필요한 정보로 활용될 수 있을 것으로 기대된다.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.22-25
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• 1995

Bacillus licheniformis SSA3 can produce a dark-brown antimutagenic pigment. The optimal conditions for production of this pigment are reached at 0.1% tyrosine, in pH 6-8, within 7-9 days, at $30^{\circ}C$, and in aerobic condition. We cloned a DNA fragment involved in pigment synthesis from Bacillus licheniformis SSA3 using a mutant strain. The cloned DNA was 7kb in size, which can produce the same pigment even in E. coli.

• KSBB Journal
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• 제27권2호
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• pp.97-102
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• 2012

In the present study, the biomass productivity of two green microalgae (Chlorella sp. and Dunaliella salina DCCBC2) were assessed in a 12 L tubular photobioreactor under optimum culture conditions. In the batch culture optimization process, the Chlorella sp. biomass was obtained as 1.2 g/L under atmospheric air as a sole $CO_2$ source and other culture conditions as follows: light intensity, temperature, pH, $NH_4Cl$ and $K_2HPO_4$ were 100 ${\mu}E/m^2/s$, $27^{\circ}C$, 7.0, 20.0 mM and 2.0 mM, respectively. On the other hand, 2.9 g/L of D. salina DCCBC2 biomass production was observed under the following conditions: light intensity, temperature, pH, $KNO_3$ and $K_2HPO_4$were 80 ${\mu}E/m^2/s$, $27^{\circ}C$, 8.0, 3.0 mM and 0.025 mM, respectively. At 1% $CO_2$ supply to the reactor, the Chlorella sp. production was reached 1.53 g/L with 25% increment under the same operating conditions. In addition, the maximum D. salina DCCBC2 biomass was observed as 3.40 g/L at 3% $CO_2$ concentration. Based on the aforementioned optimized conditions, the dilution rate and maximal biomass productivity of Chlorella sp. and D. salina DCCBC2 in the continuous cultivation were 0.4/d and 0.6 g/L/d and 0.6/d and 1.5 g/L/d, respectively.

• 한국국제농업개발학회지
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• 제30권4호
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• pp.269-276
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• 2018

1. 중앙 아시아는 5 개의 국가로 구성되어 있으며, 이 국가들은 1991년에 소련 연방에서 독립하였다. 독립 이전에는 5개 국가 모두 공산주의 통치 하에 동일한 소비에트 계획경제 체제를 가지고 있었다 2. 1991년 이래로 중앙 아시아 국가들은 정치적, 사회적, 자연적, 지리적 조건에 따라 각기 다른 개발 경로를 경험하였다. 3. 더 나은 통치 환경은 현대 기술 혁신을 장려하고 토지에 대한 신기술의 적용 및 토지에 대한 권리를 보장하도록 동기를 부여한다. 또한 상대적으로 낮은 거래 비용이 조성될 수 있도록 지원하여 생산 증대로 이어질 투자를 촉진한다. 4. 따라서 통치 환경의 개선은 농업 생산 증대에도 중요한 요인이다. 본 연구는 통치 환경과 농업 생산과의 관계를 실증적으로 분석하고 이를 검증하였다. 5. 본 연구의 결과는 농업 생산의 증대를 위하여 통치 환경의 개선이 중요함을 입증하였으며, 그 중에서도 부패 통제 및 법의 지배의 개선이 농업 생산 증대에 가장 큰 영향을 미친다는 것을 밝혔다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.440-447
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• 2009

Domestic ruminant animals are reared in diverse production systems, ranging from extensive systems under semi-arid and tropical conditions with poor feed resources to intensive systems in temperate and cold areas with high quality feed. Nitrogen (N) recycling between the body and gut of ruminants plays a key role in the adaptation to such diverse nutritional conditions. Ammonia and microbial protein produced in the gut and urea synthesized in the liver are major players in N-recycling transactions. In this review, we focus on the physiological factors affecting urea production and recycling. Sheep and buffalo probably have higher abilities to reabsorb urea from the kidney compared with cattle. This affects the degree of urea-N recycling between the body and gut at both low and high N intakes. The synthesis and gut entry of urea also differs between cattle bred for either dairy or beef production. Lactating dairy cows show a higher gut entry of urea compared with growing cattle. The synthesis and recycling of urea dramatically increases after weaning, so that the functional development of the rumen exerts an essential role in N transactions. Furthermore, high ambient temperature increases urea production but reduces urea gut entry. An increase in total urea flux, caused by the return to the ornithine cycle from the gut entry, is considered to serve as a labile N pool in the whole body to permit metabolic plasticity under a variety of physiological, environmental and nutritional conditions.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.666-674
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• 2009

An electrochemical bioreactor (ECB) composed of a cathode compartment and an air anode was used in this study to characterize the ethanol fermentation of Zymomonas mobilis. The cathode and air anode were constructed of modified graphite felt with neutral red (NR) and a modified porous carbon plate with cellulose acetate and porous ceramic membrane, respectively. The air anode operates as a catalyst to generate protons and electrons from water. The growth and ethanol production of Z. mobilis were 50% higher in the ECB than were observed under anoxic nitrogen conditions. Ethanol production by growing cells and the crude enzyme of Z. mobilis were significantly lower under aerobic conditions than under other conditions. The growing cells and crude enzyme of Z. mobilis did not catalyze ethanol production from pyruvate and acetaldehyde. The membrane fraction of crude enzyme catalyzed ethanol production from glucose, but the soluble fraction did not. NADH was oxidized to $NAD^+$in association with $H_2O_2$reduction, via the catalysis of crude enzyme. Our results suggested that NADH/$NAD^+$balance may be a critical factor for ethanol production from glucose in the metabolism of Z. mobilis, and that the metabolic activity of both growing cells and crude enzyme for ethanol fermentation may be induced in the presence of glucose.

• Journal of Microbiology and Biotechnology
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• 제23권6호
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• pp.802-810
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• 2013

This work aims at investigating the production of yellow, orange, and red natural colorants in a submerged culture of Penicillium purpurogenum DPUA 1275. For this purpose, different experimental conditions evaluating the effect of incubation time, type and size of inoculum, and different carbon and nitrogen sources were performed. Furthermore, the growth kinetics were obtained in the conditions of $10^8$ spores/ml and 5 mycelia agar discs during 360 h. These experiments showed that 5 mycelia agar discs and 336 h promoted the highest yellow (3.08 $UA_{400nm}$), orange (1.44 $UA_{470nm}$), and red (2.27 $UA_{490nm}$) colorants production. Moreover, sucrose and yeast extract were the most suitable carbon and nitrogen sources for natural colorants production. Thus, the present study shows a new source of natural colorants, which can be used as an alternative to others available in the market after toxicological studies.

• Food Science and Biotechnology
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• 제14권5호
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• pp.561-565
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• 2005

In this study, we attempted to assess the effects of lactate and com steep liquor (CSL) on the production of bacterial cellulose (BC) by Gluconacetobacter persimmonis $KJ145^T$. The optimal condition for the production of BC was a lactate concentration of 1% (w/v) and a CSL concentration of 10% (w/v). Under these optimal conditions, 6 days of fermentation produced 6.90 g/L of BC. Both the BC production yield and cell growth increased continuously until the 20th day of fermentation, by which time 17.0 g/L had been produced. In a static culture trial, in which plastic containers were used as fermentation chambers for 6 days of fermentation, the BC production yield in the group initially cultured with 500 mL medium was higher than that of the 750 and 1000 mL media. In addition, the texture of the BC was examined according to its post-treatment in order to determine conditions for optimal textural characteristics. The strength, hardness, and other characteristics of the BC were negatively correlated with sucrose concentration, but were largely positively correlated with NaCl concentration. With regards to the effect of pH on textural change, BC strength and hardness were elevated at pH 2 and 8 but reduced at pH 4 and 6, indicating that the texture of the BC is extremely sensitive to treatment conditions.