• 한국수산과학회지
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• 제28권6호
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• pp.812-813
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• 1995

Lactococcal cells are nutritionally fastidious and thus, generally cultured either in milk or M17 medium (Terzaghi and Sandine, 1975). In this study, Lactococcus cremoris wild-type (KH) and its less­proteolytic mutant (KHA1) cells were grown on the M17 medium or with modified M17 medium by replicated parallel experiments. The modified M17 medium had the same composition as M17 medium, except that lactose was replaced by glucose. Analyses of culture-broth samples, in which the M17 and the modified M17 media were used, were conducted by high-performance liquid chromatography (HPLC). But, working with these media created noisy problems in analyses of samples. Therefore, a new semi-synthetic medium was developed on the basis of nutritional requirements (Morishita et al., 1981). The composition of the semi-synthetic medium determined on the basis of the nutritional requirements and the composition of milk, is presented in Table 1. The composition of M17 medium is also presented and compared in the table. L. cremoris KH and KHA1 cells were grown again on the new synthetic medium containing glucose or lactose. The broth samples were then drawn and analyzed by HPLC. Clearer separations of fermented products were achieved from the new medium than those with the M17 and the modified M17 media. In comparison with the M17 or the modified M17 media, growth on the new medium was good (Kim et al, 1993). Additional fermentations were also carried out at a controlled pH of 7.0, where enhanced growth of lactococcal cells was obtained. In the fermentations, samples were also analyzed for the concentrations of sugar and lactic acid. The results showed that the new synthetic medium was as good as or better than the M 17 and the modified M 17 media. This is because casein hydrolysate in the synthetic medium provided a ready supply of amino acids and peptides for L. cremoris KH and KHA1 cells. Lactic acid bacteria (LAB) including Lactococcal cells have been known to be an effective means of preserving foods, at the same time as giving particular tastes in fields of dairy products. LAB also have always occupied an important place in the technology of sea products, and marine LAB have known to be present in traditional fermented products (Ohhira et al, 1988). To apply the new synthetic medium to marine LAB, two different LAB were isolated from pickled anchovy and pollacks caviar and were grown on the new media in which various concentrations of NaCl $(3, 5, 7 and 10\%)$ added. They were also grown on the medium solution in natural seawater $(35\%o\;salinity)$ and on the solution of natural seawater itself, too. As seen in Fig. 1, Marine LAB were grown best on the synthetic medium solution in natural seawater and the higher concentrations of NaCl were added to the medium, the longer lag-phase of growth profile appeared. Marine LAB in natural seawater were not grown well. From these results, the synthetic medium seems good to cultivate cells which are essential to get salted fish aged. In this study, it showed that the new synthetic medium provided adequate nutrition for L. cremoris KH and KHA1 cells, which have been used as cheese starters (Stadhouders et al, 1988). Using this new medium, the acid production capability of starter cultures could be also measured quantitatively. Thus, this new medium was inferior to the M17 or the modified M17 medium in culturing the cheese starters and in measuring fermentation characteristics of the starter cells. Moreover, this new medium found to be good for selected and well-identified marine LAB which are used in rapid fermentations of low-salted fish.

• KSBB Journal
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• 제27권6호
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• pp.335-340
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• 2012

The microalgae, Microcystis aeruginosa are able to proliferate in a wide range of freshwater ecosystem. M. aeruginosa was cultivated in 25 L and 240 L race-way reactor containing modified medium with added urea 0.2 g/L, increased $Fe^{+2}$, and decreased $Ca^{+2}$ion compared to BG11 medium. Sugar contents of M. aeruginosa grown in BG11 medium, and modified medium were 120 mg/mL and 140 mg/mL respectively. Fermentation was conducted with the extract of M. aeruginosa at $30^{\circ}C$ for 30 h, using Saccharomyces cerevisiae (Sc), Pichia stipitis (Ps), Zymomonas mobilis (Zm), and mixed-culture of these strains (Sc + Ps + Zm). Pichia stipitis (0.7%) was found to be more suitable for producing bioalcohol from M. aeruginosa extract than other strains of Saccharomyces cerevisiae (0.45%) and Zymomonas mobilis (0.61%), while mixed-cultured of these strains showed higest productivity by 1.75%. Biomass of M. aeruginosa contains the potency to be the most renewable resource for bioalcohol fermentation.

• Journal of Advanced Marine Engineering and Technology
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• 제22권5호
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• pp.670-679
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• 1998

The solution of hyperbolic equation with wave nature has sharp discontinuties in the medium at the wave front. Difficulties encounted in the numrtical solution of such problem in clude among oth-ers numerical oscillation and the representation of sharp discontinuities with good resolution at the wave front. In this work inviscid Burgers equation and modified heat conduction equation is intro-duced as hyperboic equation. These equations are caculated by numerical methods(explicit method MacCormack method Total Variation Diminishing(TVD) method) along various Courant numbers and numerical solutions are compared with the exact analytic solution. For inviscid Burgers equa-tion TVD method remains stable and produces high resolution at sharp wave front but for modified heat Conduction equation MacCormack method is recommmanded as numerical technique.

• KSBB Journal
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• 제23권1호
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• pp.18-22
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• 2008

EPS 생산량이 다양한 환경 인자 요소에 의해 달라진다는 것이 여러 연구를 통해 알려졌다(1, 5, 10, 11). 본 연구에서는 환경인자를 다음과 같은 요소 (온도, 탄소원, pH, 질소원과 탄소원)로 변화시켜 보면서 관찰하였다. 다양한 환경인자 중 EPS 생산량에 가장 큰 영향을 준 요소는 온도였다. 온도를 $37^{\circ}C$에서 $25^{\circ}C$로 낮추었을 때 EPS 생산량은 2배 이상 증가하는 것을 관찰할 수 있었다(Fig. 3(A)). 탄소원으로 galactose를 사용했을 때 EPS 생산이 가장 효율적이었으나(Fig. 2(A)), 수율 면에서는 lactose를 이용했을 때 가장 효과적이었다(Fig. 2(B)). 그러나 lactose를 사용했을 때 L. paracasei KLB 58의 성장이 매우 저조하였다. 이에 대한 균체량을 증가시킬 수 있는 방법을 모색한다면, EPS 생산하는데 있어 lactose가 휼륭한 탄소원으로 사용될 가능성이 있다고 여겨진다. 반면에, 질소원의 양을 증가시켰을 때의 EPS 생산량의 증가는 거의 변함이 없었다. 5가지 환경요소 (온도, 탄소원, pH, 질소원과 탄소원)를 변화시켜본 인자 중 질소원의 양을 변화시켰을 때 EPS 변화가 가장 적었고, 탄소원의 증가는 EPS 생산의 증가를 가져왔다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.378-381
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• 2000

The optimal conditions and properties for the immobilization of marine bacterium Pseudomonas aeruginosa BYK-2 have been determined. For the high productioon of biosurfactant, Na-alginate, PVA, modified PVA were used as a carrier. The optimal emulsifying activity on immobilized Pseudomonas aeruginosa BYK-2 showed 1036Unit (about 2.2g/L biosurfactant) in Basal salt medium(B.S.M.) at $25^{\circ}C$, 100rpm. Ca-alginate was selected the optimal bead among PVA, modified PVA and Ca-alginate. The optimal cell load in alginate bead was 10 gCWW/100g carrier. As the results of incubation of immobilized 5g Ca-alginate bead (conditions; 3% alginate, bead diameter: 2.3mm, 10% cell load) in 50m1 production medium, The emulsifying activity of 1407Unit, about 3.0g/L biosurfactant was obtained from immobilized cell after cultivation of 92hr at $25^{\circ}C$, 100rpm.

• Journal of Advanced Marine Engineering and Technology
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• 제29권2호
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• pp.202-208
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• 2005

Stress and fatigue life analyses are performed to enhance a fatigue life of a heating drum of the roller press for medium density fiberboard. The finite element method employing the submodel is used to analyze stress concentration in the journal of the heating drum. The fatigue life is evaluated by the stress-life theory. Two modified designs of the journal are suggested and evaluated to reduce the maximum stress and to increase the fatigue life Their structural reliabilities are verified in terms of the yield strength and the design life.

• 미생물학회지
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• 제36권1호
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• pp.74-78
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• 2000

본 연구에서는 Photobacterium phosphoreum의 배양 및 생체발광을 위한 최적 배지의 개발과 장기저장 후 생체발광능의 회복을 위한 최적의 저장 조건을 확립하고자 하였다. P. phosphoreum을 배양하기 위한 배지로 Luria broth(LB) 배지를 변형한 modified LB(mLB) 배지를 개발하였다. mLB 배지는 Luria broth에 1.5%의 NaCl과 3%의 글리세롤을 보정, 첨가한 배지로, 미생물 생장 및 생체 발광량이 Nutrient broth 배지보다 약 25% 가량 높은 수치를 보여주었으며, 생장 대수기에서 생장 휴지기로 넘어갈 때 생체 발광량이 최고치에 달하였다. 30% 글리세롤을 첨가하여 $-20^{\circ}C$ $-70^{\circ}C$ 및 액체질소에 3개월간 보관한 후, 배양하여 생장 및 생체 발광량을 조사한 결과에서는 $-20^{\circ}C$ 보관한 시료가 가장 좋은 결과를 보였다. 항 동결제로 5% adonitol을 첨가하여 동결 건조한 시료는 재 배양 시 adonitol를 첨가하지 않은 시료보다 16시간 이상 짧은 생장 유도기를 보여 주었고, 생체 발광량이 최고조에 달하는 시간도 빠르게 나타났다.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.763-766
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• 2010

An efficient and simple fermentation process was developed for the production of ${\gamma}$-aminobutyric acid (GABA) by Lactobacillus sakei B2-16. When the L. sakei B2-16 was cultivated in the rice bran extracts medium containing 4% sucrose, 1% yeast extract, and 12% monosodium glutamate, the maximum GABA concentration reached 660.0 mM with 100% conversion yield, showing the 2.4- fold higher GABA concentration compared with the modified MRS medium without the rice bran extracts. The GABA production was scaled-up from a laboratory scale (5 l) to a pilot (300 l) and a plant (5,000 l) scale to investigate the application possibility of GABA production to industrial fields. The production yields at the pilot and plant scales were similar to the laboratory scale using rice bran extracts medium, which could be effective for the low-cost production of GABA.

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.328-336
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• 2020

본 연구에서는 국내 낙동강 수계에서 신규하게 분리된 미세조류인 Parachlorella sp. 종의 바이오매스 및 지방산 생산성에 대한 배지의 영향을 연구하였다. 미세조류 배양에 통상적으로 사용되는 BG-11, TAP, BBM 배지를 사용하여 바이오매스 생산성은 TAP 배지에서, 지방산 축적은 BBM 배지에서 가장 잘 일어나는 것으로 확인되었고, 지방산 생산성을 향상시키기 위해 암모니아와 아세트산을 사용하는 TAP 배지의 조성을 변화하여 BBM 배지처럼 지방산 축적을 유도하며 바이오매스 생산성을 증가시킨 MTAP 배지를 개발하였다. 전체적인 바이오매스와 지방산 생산성을 높이기 위해서는 MTAP-1 배지가 적합하여 바이오매스 생산성과 지방산 생산성은 기존의 TAP 배지 대비 각각 14%, 45% 증가하였다. 생리 활성 효과로 인해 관심도가 높은 오메가-3 지방산의 생산에는 MTAP-4 배지가 가장 적합하여 바이오매스 생산성과 오메가-3 지방산 생산성이 기존 BBM 배지 대비 각각 18%, 39% 증가하여 목표 중점 생산물질(바이오매스, 총 지방산, 또는 오메가-3 지방산)의 생산성을 향상시킬 수 있는 신규 배지 2종의 조성을 개발하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.343-346
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• 2005

The isolated strain, SC2-1 was Gram-positive, catalase positive, facultatively anaerobic, oxidase negative, motile and small rods. The strain utilized sucrose, dextrose, fructose, mannitol and maltose as a sole carbon and energy source and sodium chloride required for the bacteria growth. The radical scavenging activity of the culture supernatants was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) method. This bacterium was identified based on cellular fatty acids analysis and 16S rDNA sequencing then named Exiguobacterium sp. SC2-1. The optimum culture conditions for production of antioxidant were $25^{\circ}C,$ pH 7.8 and NaCl concentration were 4%. The modified optimal medium compositions were maltose 2.5% (w/v), yeast extract 1.5% (w/v) and $KH_2PO_4$ 0.05% (w/v). Free radical scavenging activity of under optimal culture conditions were 93%.