• 한국수산과학회지
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• 제33권1호
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• pp.20-24
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• 2000

은어 자어 배합사료에 효모의 첨가효과를 조사하기 위해 K. fragilis, protoplasted K. fragilis, C. utilis, protoplasted C. utilis 및 맥주효모를 각각 $5{\%}씩$ 첨가한 6종류의 실험사료를 미립자 크럼블 형태로 제조하여 평균체중 l00 mg 전후의 자어를 대상으로 사육 실험하였다. 사료별 3반복으로 7주간 사육 실험한 후의 생존율은 protoplasted K. fragilis, C. utilis 및 protoplasted C. utilis 첨가구가 $93{\~}94{\%}$로 효모 무첨가구인 대조구의 $87{\%}$보다 유의하게 높은 경향이었으며 (P<0.05), K. fragilis 및 맥주효모 첨가구는 대조구와 유의한 차이를 보이지 않았다 (P>0.05). 증체율은 protoplasted K. fragilis 첨가구가 $149{\%}$로 대조구의 $78{\%}$보다 유의하게 높았고 (P<0.05), 그 외 실험구들과는 유의한 차이가 없었다 (P>0.05). 전어체의 단백질과 회분 함량은 모든 실험구간에 유의한 차이는 없었고 (P>0.05), 지질 함량은 K. fragilis와 맥주효모 첨가구들이 대조구보다 낮은 값을 보였다 (P<0.05). 전어체의 아미노산 조성중 Asp는 효모 첨가구들이 대조구보다 유의하게 높은 값을 보였으며 (P<0.05), 그 외 아미노산들은 실험구간에 유의한 차이가 없었다 (P>0.05). 이상의 결과로부터 C. utilis보다는 K. fragilis를 외벽 처리하여 첨가하는 것이 은어 자어의 성장과 어체 지질 성분을 더 개선시킬 수 있을 것으로 전망된다.

• 생명과학회지
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• 제24권8호
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• pp.880-886
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• 2014

제주 연안에서 분리한 해양유래미생물 14종을 이용하여 어류질병세균 4종에 대해 항균활성을 탐색하였다. 그 결과, MK-11이 그람양성균인 Streptococcus iniae, Streptococcus parauberis에 대하여 항균활성을 나타내었다. 특히 S. iniae에 대해 뛰어난 활성을 보였으며 최소 억제 농도는 $250{\mu}g/ml$로 나타났다. 최적 생장 조건은 $25^{\circ}C$, pH 6.0, 1% NaCl로 나타났으며, 최적 배지 조건은 탄소원 sorbitol, 질소원 yeast extract, 무기염 dipotassium phosphate ($K_2HPO_4$)으로 나타났다. API 50CHB kit 결과, D-sorbitol 과 D-mannitol을 추가적으로 분해하여 산을 생성하였다. 16S rDNA 염기서열 분석결과, MK-11은 Paenibacillus polymyxa, P. jamilae, P. rasilensis 와 각각 99.78%, 99.43%, 99.39%의 유사도를 나타내었다. 이처럼 다양한 특성을 지닌 Paenibacillus sp. MK-11은 그람양성균에 대한 새로운 항생물질로서의 이용가능성을 보였으며, 추가 연구를 통해 in vivo에 적용 가능할 것으로 사료된다.

• 한국환경농학회지
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• 제36권2호
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• pp.129-134
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• 2017

BACKGROUND: Yeasts are used in a variety of industries. However, most industries are biased toward Saccharomyces cerevisiae ; so we sought to explore non-conventional yeasts (NCY). This study aimed to isolate yeasts from seawater collected from the East Sea of Korea and to analyze the NCY. METHODS AND RESULTS: We first collected seawater and performed pure isolation using four kinds of medium (GPY, DOB + CSM, DG18, and SCG). In total, 314 strains and 17 genera were isolated by ITS sequencing, including Aureobasidum pullulans (236 strains), Cryptococcus (19 strains), Cystobasidium (18 strains), and Rhodotorula (9 strains). Upon in-depth analysis, A. pullulans, the most dominant genus (236 strains), was divided into Group II (147 strains), Unknown I (8 strains), and Unknown II (49 strains). CONCLUSION: In this study, a total of 314 strains were isolated from seawater; many of these yeasts have been found and reported in seawater previously. In-depth analysis of A. pullulans, showed the dominance of Group I (21 strains) and Group II (147 strains) We also discovered Unknown I (8 strains) and Unknown II (49 strains), which have not been reported previously.

• 한국양식학회지
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• 제19권1호
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• pp.40-46
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• 2006

Bacillus subtilis strain with highly active chitosanase was isolated from the intestine of Sebastiscus marmoratus (scorpion fish). It was named as Bacillus subtilis CH1 by morphological, biochemical and 165 rRNA gene analysis. The optimal conditions for chitosanase production were investigated. The optimum carbon and nitrogen sources for Bacillus stibtilis CH1 were 2% starch and 1% yeast extract respectively. Unlike other chitosanases, the expression of this chitosanase was not induced or slightly induced with chitosan. The chitosanase secreted into the medium were concentrated with ammonium sulfate precipitation and purified by gel permeation chromatography. The molecular weight of purified chitosanase was 30 kDa. The optimum pH and temperature of purified chitosanase were 5.5 and $60^{\circ}C$ respectively. The purified chitosanase was continuously thermostable at $40^{\circ}C$ and showed stable activity between pH 6.0 and 8.0. Chitosanase activity of Bacillus subtilis CH1 under optimum condition was 4.1 units/ml.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.309-312
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• 2000

A halophilic bacterium was isolated from domestic marine. The bacterium was gram negative and motile. Transmission electron micrograph after cultivating for 6-, 20-, 72-, and 144 hrs showed that it was bacilli and contained intracellular granules, which were pleomorphic, larger in density by the time and considered to be PHB since they were positive on the sudan black B staining. The presence of sodium chloride was critical, because the isolated marine bacterium could not multiply and even produce any immunostimulant in the deficiency of sodium chloride. The strain produced an immunostimulant, which was investigated for the biological characteristics. The optimal conditions for the production of the immunostimulant were 1 % dextrose and 1 % yeast extract in artificial sea water for carbon and nitrogen sources, respectively. The initial pH and growth temperature for the production were 8.0 and $30^{\circ}C$ under the presence of oxigen, respectively.

• 한국식품영양과학회지
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• 제28권6호
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• pp.1239-1243
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• 1999

The optimal medium composition for the production of carotenoid pigment from Haloarcular sp. EH 1 as a dietary for fishes were 1.0% sucrose, 1.0% yeast extract, 25% sodium chloride, 0.3% sodium citrate, 0.2% potassium chloride, 2.0% magnesium sulphate, 0.002% ferric sulphate(pH 7.0). The incubation temperate, aeration rate and agitation speed were 40oC, 100ml medium/500ml vol. shaking flask, and 180 rpm/min. The carotenoid pigment production was highest after 5 days of incubation with the light.

• KSBB Journal
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• 제24권3호
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• pp.321-326
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• 2009

Paracoccus sp.의 astaxanthin 생산성 증가를 위해 반응표면 분석법을 사용하여 최적의 배지조성을 설계하였다. Paracoccus의 성장 배지인 Marine Broth와 modified Blaszczyk 배지를 사용하여 astaxanthin 생산성을 측정한 결과 각각 0.39 mg/L, 0.40 mg/L의 astaxanthin 농도를 보였다. Modified Blaszczyk 배지의 조성을 각각 변수로 두어 가장 많은 영향을 주는 성분을 알아본 결과 $MgSO_4$와 yeast extract로 확인되었다. 중심합성계획법에 따라 $MgSO_4$ ($0.397{\sim}4.621$ g/L), yeast extract ($2.879{\sim}7.121$ g/L)를 달리하였을 때, astaxanthin 생상성에 대한 회귀식의 $R^2$은 0.894로 나타났고, 이에 따른 최대 생산량에 0.925 mg/L로 예상되었으며 이때의 $MgSO_4$와 yeast extract의 농도는 각각 2.83과 7.02 g/L로 나타났다. 이에 대한 확인실험 결과 2.83 $MgSO_4$ g/L, 7.02 yeast extract g/L에서 1.021 mg/L의 astaxanthin이 생산되었으며, 배지의 최적화에 따라 250% 이상의 생산성 증가가 확인되어졌다.

• 한국수산과학회지
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• 제36권6호
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• pp.606-613
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• 2003

This study investigated the effects of food type (condensed freshwater Chlorella, dried Chlorella, dried Spirulina, dried Schizochytrium, baker's yeast and $\omega-yeast$) and amount, and supplementation of vitamin $B_{12}$ on the growth of freshwater rotifer (Brachionus calyciflorus) in high density culture. Growth of rotifers fed condensed freshwater Chlorella was the highest and its density ranged $7.65-8.14{\times}10^3\;inds./mL.$ The primary lipid acids of rotifers fed condensed freshwater Chloyella were linoleic and linolenic, and their amount ($\%$ of total fatty acids) were $48.8\%\;and\;26.8\%,$ respectively. This suggests that condensed freshwater Chlorella would be an effective diet for high quality and quantity rotifers, which in turn serve as live food for freshwater fish larvae. Growth rate of rotifers with Chlorella supplementation increased as amount of supplementation increased up to 1.5 and 2.5 mg at 28 and $32^{\circ}C$, respectively. However, undissolved ammonia toxicity and packing volume of Chlorella in culture medium, reached the optimal conditions for the stable and effective cultivation of rotifers when amount of condensed freshwater Chlorella was 1.5 mg in dry weight per 1,000 rotifers at $28^{\circ}C\;and\;32^{\circ}C$ Growth of rotifers in condensed freshwater Chlorella with vitamin $B_{12}$ supplementation was significantly higher than that of rotifers without supplementation. However, no significant difference was found among the different concentrations of vitamin $B_{12}.$ Therefore, vitamin $B_{12}$ could improve the growth of rotifers (B. calyciflorus).

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1245-1253
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• 2014

One-step sulfuric acid saccharification of the red alga Pterocladiella capillacea was optimized, and various detoxification methods (neutralization, overliming, and electrodialysis) of the acid hydrolysate were evaluated for fermentation with the thermotolerant yeast Kluyveromyces marxianus. A proximate composition analysis indicated that P. capillacea was rich in carbohydrates. A significant galactose recovery of $81.1{\pm}5%$ was also achieved under the conditions of a 12% (w/v) biomass load, 5% (v/v) sulfuric acid, $121^{\circ}C$, and hydrolysis for 30 min. Among the various detoxification methods, electrodialysis was identified as the most suitable for fermentable sugar recovery and organic acid removal (100% reduction of formic and levulinic acids), even though it failed to reduce the amount of the inhibitor 5-HMF. As a result, K. marxianus fermentation with the electrodialyzed acid hydrolysate of P. capillacea resulted in the best ethanol levels and fermentation efficiency.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1338-1346
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• 2006

Ansamitocin P-3 is a potent antitumor agent produced by A. pretiosum. A deletion mutant of A. pretiosum was constructed by deleting the asm2 gene, a putative transcriptional repressor. The deletion mutant showed a 9-fold enhanced ansamitocin P-3 productivity. The response surface method with central composite design was employed to further optimize the culture medium composition for ansamitocin P-3 production by the deletion mutant. The concentrations of four medium ingredients, dextrin, maltose, cotton seed flour, and yeast extract, which have been reported as major components for ansamitocin production, were optimized through a series of flask culture experiments. The optimum concentrations of the selected factors were found to be dextrin 6.0%; maltose 3.0%; cotton seed flour 0.53%; and yeast extract 0.45%. The maximum titer of ansamitocin P-3 was 78.3 mg/l with the optimized composition, about 15-folds higher than the unoptimized titer of 5.0 mg/l obtained with YMG medium.