• Journal of Korean Society for Atmospheric Environment
• /
• v.24 no.3
• /
• pp.357-366
• /
• 2008

In this study, the analytical performance of trimethylamine (TMA) were investigated with respect to headspace-solid phase microextraction (HS-SPME) method. In order to induce the elution of aqueous TMA to headspace, NaOH was added as a decomposition reagent to aqueous TMA standard. By controlling the combination of three major variables for TMA extraction, the extent of extraction was compared between the two contrasting conditions for each variable (i.e., reaction time (long (L) vs short (S)), exposure temperature (30 vs $50^{\circ}C$), and exposure time (10 vs 30 min)). The results of this comparative analysis showed that the extraction efficiency for all eight types of HS-SPME combinations decreased on the order: L-30-30>L-50-10>L-30-10>L-50-30>S-30-30>S-50-30>S-50-10>S-30-10. The effect of reaction time appeared to exert significant influences on the relative recovery rate of HS-SPME at 90% confidence level. However, the effects of exposure temperature or exposure time were not so significant as reaction time. When the recovery rate of HS-SPME is compared against the direct injection of liquid standard into GC injector, it recorded as 2%. According to this comparative study, the reaction conditions for HS-SPME application can exert significant influences on the analysis of TMA.

• Korean Journal of Environmental Biology
• /
• v.21 no.1
• /
• pp.72-76
• /
• 2003

We investigated the effects of molting-hormone insecticide tebufenozide on fourth larvae of the midge C. flaviplumuon in growth development from fourth-instar to adult. Fourth-instar larvae were exposed test concentrations were chosen control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$, 60 $\mu\textrm{g}$$L^{-1}$ and 100$\mu\textrm{g}$$L^{-1}$. In control and 10 $\mu\textrm{g}$$L^{-1}$, 10~20% individuals succeed adults while low emergence rates were observed surplus 30 $\mu\textrm{g}$$L^{-1}$. Death larvae appeared a various day along the concentration. We observed the converged day: control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$ and 60~100 $\mu\textrm{g}$$L^{-1}$ were day 4 to day 18, day 13 to day 16, day 9 to day 17 and day 9 to day 15, respectively. Therefore we concerned a tendency that exposure concentration was high, death period was short. Also, due to molting hormone disruption, development of midge was postponed relatively low concentration such as 10 $\mu\textrm{g}$$L^{-1}$. The converged days of pupa stage revealed control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$ and 60~100$\mu\textrm{g}$$L^{-1}$ were day 11~15, day 16~20, day 9~15 and day 5~9, respectively. About 10% individuals grow up the pupa-stage in 60~100 $\mu\textrm{g}$$L^{-1}$ condition. Sex ratio of the emerged adults was not different in this study. Death pupae frequently appeared in day 13~16 in control, day 6~23 in 10 $\mu\textrm{g}$$L^{-1}$, day 13~16 in 30 $\mu\textrm{g}$$L^{-1}$ and day 6~16 in 60~100 $\mu\textrm{g}$$L^{-1}$.

• Food Science and Preservation
• /
• v.13 no.3
• /
• pp.389-396
• /
• 2006

In order to prepare liqueur of citrus fruit, changes of major constituents, flavonoid pH, color changes, and extract, by soaking 3 kg/6 L kumquats for $1{\sim}70$ days and 1 kg/3 L Citrus platymama for $1{\sim}50$ days in $30{\sim}95%$ ethanol solution were investigated 1.5kg of kumquats, and 1kg of citrus platymama were soaked in 3 L of $30{\sim}95%$ ethanol solution for $50{\sim}70$ days. pH and color changed largely by ethanol concentration. Glucose and fructose were more extracted in $60{\sim}95%$ ethanol concentration. Citric acid and malic acid were extracted $10{\sim}15$ times with kumquats than with Citrus platymama in 30% ethanol solution. Ascorbic acid was more extracted in 60% ethanol solution for kumquats, and in 95% ethanol for Citrus platymamma. The content of ascorbic acid was $3.19{\sim}41.91{\mu}g/mL$ in kumquats, and $21.90{\sim}30.12{\mu}g/mL$ in Citrus platymamma. $312.82{\sim}688.12{\mu}g/mL$ of rutin were extracted in 95% ethanol solution, $9.32{\sim}74.49{\mu}g/mL$ of neohesperidin were extracted in 60% ethanol as for kumquats. Rutin and neohesperidin were more extracted in 30% ethanol concentration contrary to hesperidin. Hesperidin was extracted $38.93{\sim}136.86{\mu}g/mL$ in 95% ethanol solution.

• Journal of Food Hygiene and Safety
• /
• v.20 no.4
• /
• pp.217-224
• /
• 2005

When L. monocytogenes ($10^{5}CFU/mL$) at exponential phase cells were heated for 5 min at $65^{\circ}C$ in the presence of the bacteriocin (30 BU/mL) produced by E. faecium MJ-14, the number of viable cells was markedly reduced at p < 0.05. The bactericidal effect of bacteriocin showed synergism with combination ot organic acids (citric acid or acetic acid) or chemical preservatives (sodium benzoate, sodium lactate, sodium nitrate or potassium nitrate). For example, the number of viable cells was reduced by 4.8 log units under combination of the bacteriocin (30 BU/mL) and sodium nitrate ($100{\mu}g/mL$), while it was reduced by 1.1 log unit only under single treatment of the bacteriocin after 12 k at $37^{\circ}C$. The addition of the bacteriocin (300 BU/mL) into skim milk inoculated with L. monocytogenes ($10^{5}$CFU/mL) reduced the cells by 1.5 log unit, in case of the cell suspension stored at $4^{\circ}C$ for 24 hr. Moreover, L. monocytogenes was reduced by 2 log unit when stored at $-20^{\circ}C$ for 7 days in gound pork added with 300 BU/mL of 린e bacteriocin.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.3
• /
• pp.405-410
• /
• 2015

The objective of this study was to evaluate the effects of sequential applications of ${\varepsilon}$-polylysine (EPL) or lauramide arginine ethyl ester (LAE) sprays followed by an acidic calcium sulfate (ACS) spray on inoculated chicken carcasses to reduce Salmonella (Salmonella enterica serovars including Salmonella typhimurium and Salmonella enteritidis) contamination during 6 days of storage ($4.4^{\circ}C$). Secondly, reductions of the resident microflora were studied on uninoculated chicken carcasses following the sequential application of the treatments, chilling and 10 days of storage at $4.4^{\circ}C$. The treatment of Salmonella inoculated carcasses with 300 mg/L EPL followed by 30% ACS (EPL300-ACS30) sprays reduced Salmonella counts initially by 1.5 log cfu/mL and then by 1.2 log cfu/mL (p<0.05) following 6 days of storage at $4.4^{\circ}C$. Likewise, 200 mg/L LAE followed by 30% ACS (LAE200-ACS30) treatment reduced initial Salmonella counts on poultry carcasses by 1.8, 1.4 and 1.8 log cfu/mL (p<0.05), respectively, after 0, 3, and 6 days storage. Immediately after the treatments, EPL300-ACS30 and LAE200-ACS30 both reduced Escherichia coli counts significantly by 2.6 and 2.9 log cfu/mL, respectively. EPL300-ACS30 and LAE200-ASC30 were effective in lowering psychrotroph counts by 1 log cfu/mL on day 10 when compared to the control and distilled water treatments. This study demonstrated that EPL300-ACS30 and LAE200-ACS30 were effective in reducing Salmonella on inoculated chicken carcasses both after treatment and during the storage at $4.4^{\circ}C$ for up to 6 days. In addition, reductions in psychrotroph counts indicated that these treatments might have the potential to increase the shelf-life of poultry carcasses.

• KSBB Journal
• /
• v.7 no.2
• /
• pp.149-153
• /
• 1992

Pseudomanas fluorescens was selected from mushroom and studied in both batch and continuous culture in order to find out optimum conditions for cultivation. P. fluorescens is an aerobic bacterium and antagonistic to Pseudomonas tolaasii which causes blotch disease on the mushroom cap. Cells of P. fluorescens were grown well on medium containing 30g/L of glucose, whereas the growth was inhibited with the glucose concentration at higher than 30g/L. The highest value of specific growth rate and productivity were obtained when using 10g/L of yeast extract. Optimum concentrations of $NH_4Cl$ and $(NH_4)_2SO_4$ for culture were found to be 1.0g/L and 0.1g/L respectively. Optimum concentration of $MgSO_4{\cdot}7H_2O$ used as a sulfur source was 1.0g/L. It was also found that the cell concentrations were at the maximum level when grown on the medium containing 1.0g/L of $KH_2PO_4$ and 0.1g/L of $CaCl_2$. Also, the optimum culture conditions were $30^{\circ}C$ and pH 6.0. Cultivation of P.fluorescens at high initial dissolved oxygen (D.O) value led to a decrease of bacterial productivity in batch culture. Maximum productivity was achieved at 68 for the initial D.O value.

• Cement Symposium
• /
• no.30
• /
• pp.25-30
• /
• 2003

• Microbiology and Biotechnology Letters
• /
• v.19 no.4
• /
• pp.390-397
• /
• 1991

Ethanol production by calcium alginate-immobilized baker's yeast (Saccharor/tyces cereviszae) was studied in the batch fermentation using glucose medium as a feed. Immobilied cells were stable between $30^{\circ}C$ and $40^{\circ}C$ whereas free cells were stable between $30^{\circ}C$ and $37^{\circ}C$ The beads were showed constant ethanol productivity during 720 hours (30 days) over. Fermentation characteristics of immobilized baker's yeast were examined changing the initial glucose concentration of broth in fermentation. Initial glucose concentrations employed were 50, 100, 150 and 200 g/l, respectively. In 15% gucose medium, maximum specific growth rate, maximum ethanol yield and ethanol concentration were observed as 0.092 $h^{-1}$, 0.45, 67.5 g/l, respectively.

• Korean Journal of Microbiology
• /
• v.46 no.2
• /
• pp.183-191
• /
• 2010

In this study, we isolated 179 bacterial strains using benzene, phenol, ethylbenzene, aniline, cumene, toluene as growth substrate from TCE contaminated soils and wastewaters. All the 179 strains were screened for TCE (30 mg/L) removal (growth substrate 0.2 g/L, $30^{\circ}C$, pH 7, cell biomass 1.0 g/L (w/v)) under aerobic condition for 21 days. EK2 strain using aniline showed the highest removal efficiency (74.4%) for TCE degradation. This strain was identified as Delftia acidovorans as the results of API kit, 16S rDNA sequence and fatty acid assay. In the batch culture, D. acidovorans EK2 showed the bio-degradation for TCE in the various TCE concentration (10 mg/L to 200 mg/L). However, D. acidovorans EK2 did not show the bio-degradation in the TCE 250 mg/L. D. acidovorans EK2 also show the removal efficiency (99.9%) for 12 days in the low concentration (1.0 mg/L). Optimal conditions to degrade TCE 200 mg/L were cell biomass 1.0 g/L (w/v), aniline 0.5 g/L, pH 7 and $30^{\circ}C$. Removal efficiency and removal rate by D. acidovorans EK2 strain was 71.0% and 94.7 nmol/h for 21 days under optimal conditions. Conclusion, we expect that D. acidovorans EK2 may contribute on the biological treatment in the contaminated soil or industrio us wastewater.

• Journal of Plant Biotechnology
• /
• v.32 no.2
• /
• pp.123-128
• /
• 2005

A series of experiments were performed to establish regeneration system through friable embryogenic callus (FFC) of Lilium longiflorum 'Nellie White'. Only hard and regular callus was induced from bulb scales on medium containing 2.0 mg/L dicamba and $30{\sim}90$ g/L sucrose. The induced hard callus was subcultured on medium with 2.0 mg/L dicamba and 30 g/L sucrose, and used as a material for induction of FEC. In order to induce FEC, induced hard and regular callus was chopped into $1{\sim}2\;mm$ segments, and re-cultured on medium with 2.0 mg/L dicamba and 90 g/L sucrose. FEC was induced from chopped hard calli by the subcultures of two months interval. The induction rate of FEC was enhanced when hard callus was subcultured on same medium. FEC was proliferated more than 5 times on medium with $1.0{\sim}2.0\;mg/L$ dicamba and 90 g/L sucrose. Bulblet differentiation from FEC was very favorable on MS medium supplemented with 0.1 mg/L BA, 1.0 mg/L NAA and 30 g/L maltose, but many differentiated bulblets were changed to vitrificated ones. The differentiation of normal bulblets was most effective on medium containing $0.5{\sim}1.0\%$ activated charcoal and 30 g/L sucrose.