| 1. |
- Niemi, MEK, et al.
(author)
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- 2021
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swepub:Mat__t
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| 2. |
- Kim, Jung Hun, et al.
(author)
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Production of β-carotene by recombinant Escherichia coli with engineered whole mevalonate pathway in batch and fed-batch cultures
- 2009
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In: Biotechnology and Bioprocess Engineering. - : Springer Science and Business Media LLC. - 1226-8372 .- 1976-3816. ; 14:5, s. 559-564
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Journal article (peer-reviewed)abstract
- Recombinant Escherichia coli engineered to contain the whole mevalonate pathway and foreign genes for β-carotene biosynthesis, was utilized for production of β-carotene in bioreactor cultures. Optimum culture conditions were established in batch and pH-stat fed-batch cultures to determine the optimal feeding strategy thereby improving production yield. The specific growth rate and volumetric productivity in batch cultures at 37°C were 1.7-fold and 2-fold higher, respectively, than those at 28°C. Glycerol was superior to glucose as a carbon source. Maximum β-carotene production (titer of 663 mg/L and overall volumetric productivity of 24.6 mg/L × h) resulted from the simultaneous addition of 500 g/L glycerol and 50 g/L yeast extract in pH-stat fed-batch culture.
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| 3. |
- Kim, Chang Joon, et al.
(author)
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발리올아민의 UV 분석방법 (A method for analysis by UV detector of valiolamine)
- 2011
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Patent (pop. science, debate, etc.)abstract
- A UV analysis method of valiolamine is provided to maximize detection sensitivity of valiolamine by making valiolamine to phenylisocyanate, and to enable accurate and quick HPLC analysis. CONSTITUTION: A UV analysis method of valiolamine comprises the steps of: deriving valiolamine in a microbial culture medium with a chromophore reagent to increase the detection sensitivity; and analyzing the valiolamine with increased detection sensitivity with a high performance liquid chromatography(HPLC)/UV detector. The microbial culture medium uses at least one of (i) glucose 50 g/L, soybean flour 36 g/L, peptone 5 g/L, CaCO3 4 g/L; (ii) glucose 20 g/L, corn starch 40 g/L, corn steep liquor 20 g/L, corn gluten meal 40 g/L, NH4Cl 5 g/L, NaCl 15 g/L, CaCO3 15 g/L; or (iii) glucose 10 g/L, soluble starch 50 g/L, peptone 15 g/L, corn gluten powder 30 g/L, NaCl 5 g/L, CaCO3 10 g/L. COPYRIGHT KIPO 2010
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| 4. |
- Li, He, et al.
(author)
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Enhanced production of trehalose in Escherichia coli by homologous expression of otsBA in the presence of the trehalase inhibitor, validamycin A, at high osmolarity
- 2012
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In: Journal of Bioscience and Bioengineering. - : Elsevier. - 1389-1723 .- 1347-4421. ; 113:2, s. 224-232
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Journal article (peer-reviewed)abstract
- Trehalose production in Escherichia coli DH5α was explored by overexpressing otsBA operon encoding trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase. Production and subsequent degradation of trehalose resulted in low production of trehalose in engineered cells overexpressing otsBA, which was primarily due to the concomitant expression of endogenous trehalase. Through an in vitro enzyme assay and flask cultures of engineered cells, trehalase expression was shown to be directly related to the expression of otsBA rather than osmotic stress. Validamycin A effectively inhibited E. coli trehalase and the intracellular accumulation of trehalose was markedly enhanced in the presence of validamycin A at an optimal concentration in the medium. The trehalose production was further increased upon growth in a hypertonic medium in the presence of validamycin A, with most trehalose accumulating as an intracellular product. The highest titer was obtained when otsBA expression was induced by a medium-copy vector, ptrc99A, with 0.5mM of isopropyl β-d-1-thiogalactopyranoside. Trehalose titer was 1.7 g/L in controlled bioreactor cultures using synthetic M9 medium supplemented with 40 g/L glycerol, 0.1mM validamycin A, and 300 mM NaCl.
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| 5. |
- Li, He, et al.
(author)
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Quantitative analysis of valiolamine through pre-column derivatization with phenylisocyanate using high-performance liquid chromatography with UV detection : Selection of reagent, identification of derivative and optimization of derivatization conditions
- 2009
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In: Journal of Pharmaceutical and Biomedical Analysis. - : Elsevier. - 0731-7085 .- 1873-264X. ; 49:4, s. 957-963
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Journal article (peer-reviewed)abstract
- This report describes the improved quantitative determination of valiolamine in a medium for microbial culture using high-performance liquid chromatography with UV detection. Valiolamine aqueous solution was dried, dissolved in dimethyl sulfoxide and derivatization performances of phenylisocyanate (PHI), 1-fluoro-2,4-dinitrobenznene and 1-naphthylisothiocyanate were compared in the presence of triethylamine. The PHI was chosen as the most suitable derivatization reagent and the valiolamine-PHI derivative was identified by thin-layer chromatography and electrospray ionization mass spectrometry. The derivative eluted at 10.5 min on a reverse-phase column using a mobile phase composed of 10% acetonitrile in water containing 0.5 mM sodium octyl sulfate (pH 3.0), at a column flow rate of 1.0 mL/min with UV detection at 240 nm. The optimum conditions for derivatization were a reaction temperature of 30 degrees C, reaction time of 30 min, and PHI concentration higher than 33.6 mM. Calibration curves were linear in the range of 0.99-19.95 microg/mL for the standard solutions and 24.9-99.7 microg/mL for the spiked sample. The proposed method was validated and proven to be selective, accurate and precise and suitable for the quantitative analysis of valiolamine in medium for microbial cultures.
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