• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.161-166
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• 2001

The influence of the consumed carbon to nitrogen (C/N) ratio on mycelial morphology was investigated in cultures of Mortierella alpina using shake flasks. The consumed C/N ratio was varied from 5 to 32 under the condition that the total initial amount of the carbon and nitrogen sources was 50g/L. The whole mycelia and filamentous mycelia exhibited no relationship with the consumed C/N ratio below a consumed C/N ratio of 20 in the presence of either excess carbon or excess nitrogen. However, when the consumed C/N ratio increased higher than 20, the mycelial sizes increased in proportion to the consumed C/N ratio. However, the area ratio of filamentous mycelia to total mycelia was found to be independent of the consumed C/N ratio, and remained constant at 0.82. In the case of a fixed consumed C/N ratio of 20, the whole mycelia and filamentous mycelia increased in proportion to the degree of the medium strength, yet the area ratio of filamentous mycelia to total mycelia remained unchanged at 0.76. Accordingly, these results show that fungal morphology and mycelial size are both affected by the ratio of carbon to nitrogen. The findings of the current study will be helpful in obtaining the efficient production of useful bioproducts from fungal cultures.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.237-242
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• 2004

Cell growth and the production of pullulan by Aureobasidium pullulan HP-2001, the UV-induced mutant of A pullulans ATCC 42023, increased with increased concentration of glucose up to 15.0% (w/v). Maximal production of pullulan in the flask scale was 27.65 g/l, when concentrations of glucose and yeast extract were 15.0 and 0.25% (w/v), respectively. Maximal conversion rate of pullulan from glucose as the carbon source was 0.37, when those of glucose and yeast extract were 5.0 and 0.15% (w/v), respectively. On the basis of total amount of pullulan, the conversion rate of pullulan from glucose, and utilization rate of glucose to cell mass and pullulan by A. pullulans HP-2001, the optimal concentrations of glucose and yeast extract for the mass production of pullulan were determined to be 10.0 and 0.25% (w/v), respectively, at which concentrations the production of pullulan and its conversion rate were 27.14 g/l and 0.27, respectively. Maximal production of pullulan with optimized concentrations of carbon and nitrogen sources by A. pullulans HP-200l in a 7-1 bioreactor was 32.12 g/l for 72 h culture, and that in a 100-1 bioreactor with the inner pressure of $0.4 kgf/cm^2$ was 36.87 g/l. Increased inner pressure of a 100-1 bioreactor resulted in a higher concentration of dissolved oxygen in the medium, which might enhance the production of pullulan by A. pullulans HP-2001.

• Plant Biotechnology Reports
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• 제4권4호
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• pp.261-267
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• 2010

We describe culture conditions for a high-efficiency in vitro regeneration system of Papaver nudicaule through somatic embryogenesis and secondary somatic embryogenesis. The embryogenic callus induction rate was highest when petiole explants were cultured on Murashige and Skoog (MS) medium containing 1.0 mg $1^{-1}$ ${\alpha}$-naphthaleneacetic acid (NAA) and 0.1 mg $1^{-1}$ 6-benzyladenine (BA) (36.7%). When transferred to plant growth regulator (PGR)-free medium, 430 somatic embryos formed asynchronously from 90 mg of embryogenic callus in each 100-ml flask. Early-stage somatic embryos were transferred to MS medium containing 1.0 mg $1^{-1}$ BA and 1.0 mg $1^{-1}$ NAA to germinate at high frequency (97.6%). One-third-strength MS medium with 1.0% sucrose and 1.0 mg $1^{-1}$ $GA_3$ had the highest frequency of plantlet conversion from somatic embryos (91.2%). Over 90% of regenerated plantlets were successfully acclimated in the greenhouse. Secondary somatic embryos were frequently induced directly when the excised hypocotyls of the primary somatic embryos were cultured on MS medium without PGRs. Sucrose concentration significantly affected the induction of secondary embryos. The highest induction rate (89.5) and number of secondary somatic embryos per explant (9.3) were obtained by 1% sucrose. Most secondary embryos (87.2-94.3%) developed into the cotyledonary stage on induction medium. All cotyledonary secondary embryos were converted into plantlets both in liquid and on semisolid 1/3-strength MS medium with 1.0% sucrose.

• Journal of Animal Science and Technology
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• 제51권6호
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• pp.527-536
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• 2009

A potent protein degrading bacterium was isolated from soil samples of different environments. Polyphasic taxonomic studies and phylogenetic 16S rRNA sequence analyses led to identify the isolate IB No. 11 as a strain of Bacillus subtilis. The isolated strain was recognized to produce protease constitutively, and the maximum production (1.64 units/ml) was attained in a shake flask culture when the isolate was grown at $40^{\circ}C$, for 32 h in basal medium supplemented with starch (0.25%) and gelatin (1.25%) as sole carbon and nitrogen source, respectively. The optimum pH and temperature for the protease activity were determined to be pH 7.0 and $50^{\circ}C$, respectively. $Ca^{2+}$ and $Mn^{2+}$ enhanced remarkably the protease activity but neither showed positive effect on the protease's thermal stability. In addition, it was observed that the protease was fairly stable in the pH range of 6.5-8.0 and at temperatures below $50^{\circ}C$, and it could be a good candidate for an animal feed additive. The inhibition profile of the protease by various inhibitors indicated that the enzyme is a member of serine-proteases. A combination of UV irradiation and NTG mutagenesis allowed to develop a protease hyper-producing mutant strain coded as IB No. 11-4. This mutant strain produced approximately 3.23-fold higher protease activity (6.74 units/mg) than the parent strain IB No. 11 when grown at $40^{\circ}C$ for 32h in the production medium. The protease production profile of the selected mutants was also confirmed by the zymography analysis.

• 생명과학회지
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• 제6권2호
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• pp.135-141
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• 1996

양식을 위한 먹이사료로서 가능성 있는 효모균주를 연구하였다. Kluyveromyces fragilis효모와 Candida utilis 효모의 최대 비증식 속도와 바이오매스 효율은 Saccharomyces cervisiae 효모에 비하여 굉장히 높은 값을 나타내었다. 따라서, 이 연구는 대량생산을 위하여, 플라스크 배양을 통한 이들 두 효모균들의 성장특성에 그 초점을 맞추었다. 5% 접종량을 가지고 실험한 결과, 가장 좋은 $\mu$$_{max}$ 와 OD$_{max}$ 값들은 K, fragilis는 2.5% fructose 배지에서, C. utilis는 2% YE배지에서 각각 얻었으며, 이 때의 이 값들은 K. fragilis는 0.73 hr$^{-1}$1 와 3.00을 C. uitilis는 0.59 hr$^{-1}$ 와 2.80으로 밝혀졌다. 또한, 아연과 염의 초기종도가 증가할수록 균성장에 있어서의 우도기는 증가하였으며, 접종량이 증가할수록 유도가는 감소하였다. 두 효모균은 3.5% 염농도에서 비교적 잘 자랄 수 있었으며, C. utilis 효모균만이 아연을 이용할 수 있었다.

• 한국식품영양과학회지
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• 제24권3호
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• pp.434-439
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• 1995

단세포 단백질 자원으로 이용 가능한 균주로 알려진 Candida utilis ATCC 42416 균체를 생산하기 위하여 무를 파쇄하여 얻은 무즙을 배지로 균체배양 실험을 하였다. 무즙의 수용성 고형물과 총 당량은 각각 5.0~8.8 Brix와 3.5~6.5%였다. C. utilis ATCC 42416 균주를 무즙에 접종하여 $30^{\circ}C$에서 200rpm으로 진탕 배양하였을 때 24시간 이내에 증식이 끝났으며, 단위 소모당에 대한 최대 균체 생산량은 당농도 1% 회석 무즙에서 L당($5\;\times\;DCRI$) 21.5g의 건조균체를 생산하였다. 5배 회석무즙에 약간의 영양소 glucose(2.0%), yeast extract(0.2%), peptone(0.2%), ammonium sulfate(0.2%) 및 $KH_2PO_4(0.2%)$ 등을 각각 보강하여도 증식 속도, 균체생산 및 세포 단백질 함량 등에 차이가 거의 없어서 무즙자체가 C. utilis ATCC 42416 균체 생산에 좋은 기질이었음을 알 수 있다.

• KSBB Journal
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• 제13권2호
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• pp.214-219
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• 1998

Polymerase chain reaction(PCR) was conducted to obtain the gene encoding glucose oxidase(GOD) from Aspergillus niger(ATCC 2110) and the DNA sequence determined was coincided with published GOD sequence from A. niger. Recombinant transforming vector containing GOD and hygromycin B(hyg.B) resistant gene(hph) was constructed and used for further transformation of A. niger ATCC 2110. Selectivity of hyg.B against A. niger differed depending on which media were used i.e., nutrient-rich media such as potato dextrose agar(PDA) and complete medium(CM) showed only 50% growth inhibition at 400 $\mu$m ml$^-1$ of hyg.B while the minimal media inhibited mycelial growth completely at 200 $\mu$m ml$^-1$ of hyg.B. Twenty to sixty putative transformants were isolated from the hyg.B-containing minimal top agar, transferred successively onto alternating selective and nonselective media for a mitotic stability of hyg.B resistance and, then, single-spored. Among the stable transformants, the transformant(GOD1-6) grown by flask culture showed the considerable increase of extracellular GOD activity, which was estimated to the degree of 50% - 100% comparing to that of wild type. Transformation of tGOD1-6 was resulted from integration of the vectors into heterologous as well as homologous regions of the A. niger genome. Southern blot analysis revealed that there were two independent integrations of vector into fungal genome and one into the GOD gene due to homologous recombination. In addition, GOD activity and sodium gluconate production when tGOD1-6 was fed-batch fermented were enhanced 11 fold and 2.25 fold, respectively, compared to that of the wild type.

• KSBB Journal
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• 제9권4호
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• pp.428-435
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• 1994

탄소원으로 초기 glucose 농도와 초기 maltose 농도를 5g/$\ell$, 109/$\ell$, 20g/$\ell$ 로 한 후 Bacillus a amyloliquefaciens(ATCC 23350 ) 균주를 이용하여 플라스크 배양시의 세포 성장과 생성물 생성에 대한 연구를 수행하였다. 균주의 최대 건조세포농도는 초기 maltose 농도가 증가할수록 증가하였으나, glu­c cose에서는 초기 농도가 109/$\ell$일 때 가장 높았다 최대 비성장속도는 초기 glucose농-토가 109/$\ell$ 일 때 $0.060(hr^{-1})$로 가장 높으며, maltose에서는 초기 농도가 5g/P 얼 때 $0.042(hr^{-1})$이였다. 균주에 의해 생성되는 최대 a-amylase 생산은 초기 maltose 농도가 109/P 얼 때 l49.0unit/ml로 가장 높았으며, 초기 maltose 농도가 증가할수록 증가하였다. 최대 비생성속도는 초기 maltose 농도가 5g/$\ell$ 일 때 3.26unit/ mg- hr로 가장 높았으며 , glucose보다는 maltose에서 더 높았다. 균주에 의해 생성되는 최대 ${\alpha}$-acetic acid는 탄소원의 초기 농도가 증가함에 따라 감소하며, 초기 glucose 농도 109/$\ell$ 일 때 0.94g/$\ell$ 로 가장 많이 생성되였고, lactic acid는 탄소원의 초 기 농도가 증가할수록 증가하였으며, 초기 maltose 농도가 20g/$\ell$일얼 때 8.20g/$\ell$ 로 가장 많이 생성되였 다.

• KSBB Journal
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• 제15권1호
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• pp.27-34
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• 2000

남해안 유류 오염지역으로부터 유류분해능이 우수한 균주를 선별하여 동정한 결과 Pseudomonas aeruginosa로 동정되었으며, Pseudomonas aeruginosa BYK-2로 명명하였다. 균 성장 및 생물 유화제 생산을 위한 최적배양온도, 시간, pH, NaCl 농도는 각각 $25^{\circ}C$, 48시간, 7.0 이었으며, NaCl은 첨가하지 않았을 때 가장 많은 양의 생물유화체가 생산되었다. 본 균주의 경우, 1%(w/v) arabian light 원유와 bunker C oil을 기질로 7일간 배양한 결과 92.1%(w/w)와 76.2%(w/w)가 생분해되었다. n-hexadccane 에 대한 세포부착능이 실험에서는 탄화수소화합물들(arabian light 원유, kuwait 원유, bunker C 유, n-paraffine, n-hexadecane, n-tetradecane)을 기질로 배양했을때는 모두 80% 이상의 높은 세포부착능을 나타냈으며, 지방산들(oleic acid, olive oil, lecithin)중에는 lecithin을 기질로 배양했을 때 91.5%로 가장 높은 세포부착능을 나타냈어다. 또한 당들(arabinose, trehalose, dextrose, galactose, lactose, fructose, maltose, sorbitol, sucrose)을 기질로 했을 경우 arabinose, galactose, sorbitol, sucrose를 제외하고는 대부분 70%이하의 세포부착능을 나타냈다.

• 한국미생물·생명공학회지
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• 제32권2호
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• pp.123-127
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• 2004

토양으로부터 oleic acid 를 탄소원으로 이용하여 MCL-PHA의 생산능이 우수한 균주를 분리하여 Pseudomonas sp. MBEL21이라 명명하였다. Pseudomonas sp. MBEL21의 PHA함량을 증가시키기 위하여 여러 가지 필수 영양분의 제한 조건에서 배양한 결과, 인산이 제한된 조건에서 가장 높은 함량의 PHA를 축적하였다. 고농도의 MCL-PHA생산을 위한 Pseudomonas sp. MBEL21의 유가식 배양 전략을 개발하여 28.1 wt％의 함량으로 23 g/L. MCL-PHA를 생산하였다. 또한, 분리된 Pseudomonas sp. MBEL21을 olive oil을 탄소원으로 이용하여 배양한 결과 9.3 wt％의 PHA가 축적되어졌으며, MCL-hydroxyalkanoate와 함께 3-hyoxy-butyrate 의 단량체들로 이루어진 PHA가 확인되어졌다. 이러한 결과들은 분리된 신규 Pseudomonas sp. MBEL21이 저가의 olive oil로부터 생분해성 탄성체의 응용분야를 갖는 MCL-PHA를 효율적으로 생산할 수 있다는 것을 보여준다.