• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.686-691
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• 2012

The objective of this research is to present method development and validation for the simultaneous determination of lutein and zeaxanthin using ultra performance liquid chromatography (UPLC). Also, rapid quantification was performed on six green leafy vegetables (Allium tuberosum, Aster scaber, Hemerocallis fulva, Pimpinella brachycarpa, Sedum sarmentosum and Spinacia oleracea) that are commonly consumed in Korea. Separation and quantification were successfully achieved with a Waters Acquity BEH C18 ($50{\times}2.1mm$, $1.7{\mu}m$) column by 85% methanol within 5 min. Two compounds showed good linearity ($r^2$ > 0.9968) in $1-150{\mu}g/mL$. Limit of detection (LOD) and quantification (LOQ) for lutein and zeaxanthin were 1.7 and 5.1 g/mL and 2.1 and 6.3 g/mL, respectively. The RSD for intra- and inter-day precision of each compound was less than 10.69%. The recovery of each compound was in the range of 91.75-105.13%. Aster scaber and Spinacia oleracea contained significantly higher amounts of lutein ($4.06{\pm}0.24$ and $3.97{\pm}0.10mg$/100 g of fresh weight), respectively.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.411-415
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• 2009

Some microorganisms are capable of leaching Mn(II) from nonsulfidic manganese ores indirectly via nonenzymatic processes. Such reductive dissolution requires organic substrates, such as glucose, sucrose, or galactose, as a source of carbon and energy for microbial growth. This study investigated characteristics of Mn(II) leaching from manganese nodules by using heterotrophic Bacillus sp. strain MR2 provided with corn starch as a less-expensive substrate. Leaching of Mn(II) at 25.6 g Mn(II) $kg^{-1}$ nodule $day^{-1}$ was accompanied with cell growth, but part of the produced Mn(II) re-adsorbed onto residual $MnO_2$ particles after 24 h. Direct contact of cells to manganese nodule was not necessary as a separation between them with a dialysis tube produced similar amount [24.6 g Mn(II) $kg^{-1}$ nodule $day^{-1}$]. These results indicated an involvement of extracellular diffusible compound(s) during Mn(II) leaching by strain MR2. In order to optimize a leaching process we tested factors that influence the reaction, and the most efficient conditions were $25\sim35^{\circ}C$, pH 5~7, inoculum density of 1.5~2.5% (v/v), pulp density of 2~3 g/L, and particle size <75 ${\mu}m$. Although Mn(II) leaching was enhanced as particle size decrease, we suggest <212 ${\mu}m$ as a proper size range since more grinding means more energy consumption The results would help for the improvement of bioleaching of manganese nodule as a less expensive, energy-efficient, and environment-friendly technology as compared to the existing physicochemical metal recovery technologies.

• KSBB Journal
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• v.23 no.6
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• pp.513-518
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• 2008

This paper described the extraction/purification of $\beta$-carotene from recombinant E.coli and evaluation of anti-wrinkle activity of purified $\beta$-carotene. No significant differences in extraction yields were observed when hexane or isobutyl acetate was used. However, extraction from wet-cell cake resulted in 2-fold higher amount of $\beta$-carotene than that from dry cells. Disruption of 5 g-wet cells by ultrasonic homogenizer, acetone dehydration, extraction with isobutyl acetate resulted in 36 mg of $\beta$-carotene corresponding to 61.2% of recovery. The formation and separation of $\beta$-carotene crystal improved the purity. 633 mg of $\beta$-carotene crystal with 93% purity was obtained from 223 g/L of wet-cell cake harvested from 2.5-L fed-batch culture broth. The cultures of normal human primary fibroblast were performed to investigate the effect of $\beta$-carotene on cytotoxicity as MTT assay and anti-wrinkle activity as collagen synthesis assays. $1.7{\mu}M$ of $\beta$-carotene was found to be optimal concentration at which 1.4-fold higher amount of collagen was synthesized than that in absence of $\beta$-carotene. This indicates that highly purified $\beta$-carotene can be obtained from recombinant E.coli by applying simple method with less toxic solvent and can be used in functional cosmetics as anti-wrinkle agent.