• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.204-211
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• 2011

To yield high concentrations of protein expressed by genetically modified Escherichia coli, it is important that the bacterial strains are cultivated to high cell density in industrial bioprocesses. Since the expressed target protein is mostly accumulated inside the E. coli cells, the cellular product formation can be directly correlated to the bacterial biomass concentration. The typical way to determine this concentration is to sample offline. Such manual sampling, however, wastes time and is not efficient for acquiring direct feedback to control a fedbatch fermentation. An E. coli K12-derived strain was cultivated to high cell density in a pressurized stirred bioreactor on a pilot scale, by detecting biomass concentration online using a capacitance probe. This E. coli strain was grown in pure minimal medium using two carbon sources (glucose and glycerol). By applying exponential feeding profiles corresponding to a constant specific growth rate, the E. coli culture grew under carbon-limited conditions to minimize overflow metabolites. A high linearity was found between capacitance and biomass concentration, whereby up to 85 g/L dry cell weight was measured. To validate the viability of the culture, the oxygen transfer rate (OTR) was determined online, yielding maximum values of 0.69 mol/l/h and 0.98mol/l/h by using glucose and glycerol as carbon sources, respectively. Consequently, online monitoring of biomass using a capacitance probe provides direct and fast information about the viable E. coli biomass generated under aerobic fermentation conditions at elevated headspace pressures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.85-93
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• 2012

We study on the distribution characteristics of antifouling agents such as Sea-nine 211, Irgarol 1051, Diuron using HS-SPME method in southwestern coast of Korea. Short half-life of Sea-nine 211 was distributed in very low concentrations and/or below detection limits in all of the sampling points, both water and sediments samples. Irgarol 1051 was detected to have the highest concentration respectively $6.98{\mu}g/L$, 28.50 ng/g-dry wt in the seawater and sediments, and regional distribution characteristics did not appeared. Strong bioaccumulation and long half-life of Diuron was distributed higher concentration than in all sampling point and was analyzed to have the highest concentration(3882.22 ng/g-dry wt) Mo7(Mokpo)'s sediment. Irgarol 1051 and Diuron distributed in the shipbuilding industry and ship marina are located just at the point to found in high concentrations. In addition, the distribution of the antifouling agent materials were lower in concentration than in inner bay to outter bay in sediments. Antifouling agent materials from these results were contaminated high potential from port and shipbuilding industry located in inner bay.

• Korean journal of food and cookery science
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• v.22 no.6 s.96
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• pp.774-782
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• 2006

Flavor components in fresh Codonopsis lanceolata cultivated on a wild hill were detected by headspace sampling(HSS) method and GC-MS equipped with a VB-5(5% phenylmethyl polysiloxane) column. The 167 volatile compounds that were detected, consisted of 28 terpenes and terpene alcohols, 34 hydrocarbon, 31 alcohols, 13 aldehydes and ketones, 25 esters, 6 acids, 10 ethers and 20 miscellaneous components. The ten major volatile flavor components, comprising about 58% of the total, were dl-limonene (10.2%), ${\alpha}$-guaiene (9.0%), 2,2,6-trimethyl-octane (8.6%), hexadecane (8.0%), isolongifolan-8-ol (4.2%), 2,4,4-trimethyl-1,3-pentanediol diisobutyrate (4.1%), ${\beta}$-selinene (3.9%), 2,2,3-trimethylnonane (3.6%), 3-methyl-5-propyl-nonane (3.1%), and ledene (3.1%). The unique aroma of fresh Codonopsis lanceolata described by sensory evaluation was green, earthy, camphoraceous and aldehydic. The components attributed to green or camphoraceous flavor such as 1-hexanol, 2-methylhexan-3-ol, 3-hexen-1-ol, cis-3-hexenyl butyrate, ethylhexanol, hexyl acetate, trans-2-hexen-1-ol, camphor, longiborneol and menthol were not included in the ten or twenty major volatile components which had the largest peak area in descending order. We concluded that the intensity of green and camphoraceous flavor might be used as an indicator of the freshness of Codonopsis lanceolata.