• KSBB Journal
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• v.14 no.1
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• pp.91-95
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• 1999

The objective of this work was to improve bioluminescence stability of Photobacterium phosphoreum when it stored in view of developing continuous on-line monitoring system for pullutants. Long-term experiments were made to determine the effect of immobilization and storage temperature on the maintenance and stability of bioluminescence from luminescent bacteria. The immobilized cells of P. phosphoreum were compared with free cells in terms of maintenance of bioluminescence at room temperature. The bioluminescence of cells immobilized showed higher bioluminescence intensity that free and strontium bioluminescence stability was investigated with free and immobilized cells stored at $20^{\circ}C,\; 4^{\circ}C,\; -20^{\circ}C\;and\;-70^{\circ}C$for 20 days. Both free and immobilized cells stored at $4^{\circ}C$ emitted a stable bioluminescence while the bioluminescence markedly decreased with those stored at $20^{\circ}C,\;-20^{\circ}C\;and\; -70^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.706-709
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• 2002

Bacterial bioluminescence has been known to be a highly valuable reporter system for its potential application as an effective and simple environmental monitoring method for toxic compounds. In this short report, we constructed a streptomycetes-Escherichia coli shuttle vector-containing bioluminescence system and evaluated its potential application for toxic compounds monitoring. The luxAB biolurninescence genes from Vibrio harveyi were cloned into a streptornycetes-E. coli shuttle vector (named pESK004) and functionally expressed in Streptomyces lividans. The recombinant S. lividans containing pESK004 exhibited an optimal biolurninescence at the optical density ($OD_{600\;nm}$) of 0.4-0.5 and aldehyde concentration of 0.005%. When the recombinant bioluminescence streptomycetes was exposed to a toxic compound such as heavy metals, chlorinated phenols, or pesticides, the bioluminescence was decreased proportionally to the concentration of toxic compound in the assay mixture. The $EC_{50}$ (effective concentration to decrease 50% of the bioluminescence prior to exposure) values in the recombinant biolurninescence streptomycetes for mercury, 2,4-dichlorophenol, and malathion were measured at 2.2 ppm, 144.0 ppm, and 82.4 ppm, respectively. The degree of sensitivity and specificity pattern toward these toxic compounds characterized in this recombinant bioluminescence streptomycetes were unique when compared with previously reported bacterial bioluminescence systems, and this revealed that a recombinant bioluminescence streptomycetes might provide an alternative or complementary system for potential environmental monitoring.

• KSBB Journal
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• v.14 no.4
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• pp.403-407
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• 1999

Various materials including sodium alginate, k-carragreenan, collagen and polyacrylamide were studied in order to maintain stability of bioluminescence of P. phosphoreum for the purpose of continuos monitoring of toxic subtances. Collagen and polycryamide were shown to be inadequate for immobilization of p. phosphoreum since the bioluminescence decreased when cells were mixed with such materials. In case of k-carrageenan, the bioluminescence was stable when compared with collagen and polyacryamide. However, the k-carrageenan was not suitable for immobilization of p. phosphoreum as cells could not be mixed with the material properly in temperature at which gel formation already occurred. P . phosphoreum must be treated at low temperature below that of gel formation since these are psychrophilic luminescent bacterial. When cells were immobilized on sodium alginate, the bioluminescence was stably maintained for 20 minutes.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.242-249
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• 1997

Stability of bioluminescence was investigated with Photobacterium phosphoreum immobilized on the strontium alginate in order to develope continuous real time monitoring of pollutants. The stability of bioluminescence emission was improved by prolonged aging time. The aging time of ${\geq}40$ min and the cell concentration of ${\leq}0.6\;of\;OD_660$ were selected for the immobilization of P. phosphoreum to give linearity between cell concentrations and bioluminescence intensity. In sensitivity tests using phenol, it was found that this compound quenched bioluminescence proportional to the concentration without lowering of cell growth. The lower value for maximum quenching ($q_s$) and higher dissociation constant ($K_s$) were observed with strontium-alginate immobilized cells compared to free cells. The response of bioluminescence to toxicants was evaluated with the immobilized luminescent bacteria. The sensitivity of the immobilized cells was found to be good in response to toxicants, 4-nitrophenol, salicylate and cadmium, when evaluated with a specific rate of bioluminescence quenching.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1345-1348
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• 1999

The utility of a bioluminescence adenosine triphosphate(ATP) assay method for estimating bacterial levels in mackerel(Scomber japonicus) was investigated. Mackerel was stored at $1^{\circ}C$ throughout 10 days and its RLU(relative light unit) and APC(aerobic plate count) was determined. The ATP bioluminescence assay was validated during the storage of 32 samples, resulting in an agreement between the ATP assay and standard plate count methods of over 90% credibility. Therefore, ATP bioluminescence assay was considered as a rapid and near real-time means in estimating the microbial load on mackerel skin.

• KSBB Journal
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• v.14 no.3
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• pp.342-350
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• 1999

Photobacterium phosphoreum was used in order to study response to heavy metal including $HgCl_2$, $CdCl_2$, $MnSO_4$ and $ZnSO_4$ in view of developing monitoring system for toxic substances. The concentrations of heavy metal causing 50% reduction($EC_{50}$) in bioluminescence intensity were determined with both free and immobilized P. phosphoreum. The bioluminescence responses were examined at various concentrations of heavy metal after 10, 20 and 30 min of exposure. The linear correlation between Gamma values and concentrations of heavy metal was obtained and $EC_{50}$ was calculated from the linear correlation. The significant inhibitory concentrations for bioluminescence emission were found to be 0.05mg/L for $HgCl_2$, 25mg/L for $CdCl_2$, 50mg/L for $MnSO_4$ and 12.5mg/L for $ZnSO_4$, respectively. The free cell and disc type were shown to be more sensitive to heavy metal than cells mixed with Na-alginate or immobilized on Sr-alginate. However, the linear regression curves were derived from the Sr-alginate immobilized cells indicating the immobilization method is a useful tool for monitoring of heavy metal under more stable condition of bioluminescence.

• Journal of Ginseng Research
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• v.25 no.3
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• pp.127-129
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• 2001

Bioluminescence technique was applied to ginseng powders. ATP bioluminescence can be used as a rapid method that can be implemented for microbiological monitoring of contaminated ginseng powders. The RLU (relative light units) of ATP was proportion to bacterial CFU (colony forming units) when in high contaminated ginseng powders ($\geq$ about 1.0$\times$10$^4$CFU/g). However, when in low contaminated ginseng powders ($\times$10$^4$CFU/g), the RLU was not proportion to CFU, respectively.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.484-490
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• 1999

Various materials including sodium alginate, k-carrageenan, collagen and polyacrylamide were studied in order to maintain the stability of bioluminescence of Photobacterium for the monitoring of volatile toxic substances. Kinetic parameters of specific rate($\mu$), and gamma(${\gamma}$) value were determined for the relationship between bioluminescence of immobilized P. phosphoreum and toxic substances. The bioluminescence intensity was found to be proportional to the concentration of toxic substances and the free cells were shown to be more sensitive than immobilized cells when volatile substances were exposed to the cells. Bioluminescence increased slightly after several minutes, which was due to the volatility of toxic compounds. Furthermore, P. phosphoreum immobilized on strontium alginate was better than cells immobilized on sodium alginate for the response to substances used.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.45-51
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• 2000

Photobacterium phosphoreum was used for the study of bioluminescence response to toxic substances including phenol, As2O3, SoO2, and CrO3 in view of developing monitoring system. measurement of inhibition of bioluminescence in P. phosphoreum has been proposed as a sensitive and raped procedure to monitor toxic substances. The concentration of toxic substance causing 50% light reduction(EC50) in bioluminescence intensity was determined with free and immobilized P. phosphoreum, The minimum inhibitory concentrations (MICs) for bioluminescence emission were found to be 400ppm for As2O3, 800ppm for phenol, 60ppm for SeO2 and 60ppm for CrO3 , respectively. The linear correlation between Gamma value and the concentration of toxic substances was obtained and EC50 wa calculated from the linear correlation. The free cells were shown to be more sensitive to toxic substances than cells immobilized on Sr-alginate and Ca-alginate. However, the linear regression curves were derived from the Sr-alginate immobilized cells indicating the immobilization method in s useful tool for monitoring of toxic substances under the more stable condition of bioluminescence.

• Korean journal of food and cookery science
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• v.16 no.2
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• pp.195-201
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• 2000

An investigation was conducted to evaluate the hygienic status of university foodservice operation by using conventional swabbing technique plus standard plate count and ATP bioluminescence assay. The results of the study were as follows: 1) For all kitchen boards, knives, feeding trays, and dish towels tested, there was an overall agreement at 84.7% level between the results obtained using ATP bioluminescence and plate count when using a pass/fail cut-off of 3$\times$ control values for ATP assay and 40 CFU(colony forming unit)/㎠ for plate count. 2) The agrement rate between ATP assay and standard plate count was 87.5% for the samples before use, 29.2% for those during use, and 42.7% for those after cleaning and sanitizing. 3) The plate counts of three university foodservice operations for kitchen board, kitchen knife, feeding tray and dish towel were within the acceptable limits when tested before using. However, none of them were within the acceptable limits when tested during using and after cleaning and sanitizing. 4) Above results suggested that an immediate action needs to be taken to reduce the potential danger of cross-contamination and also effective sanitary control methods needs to be developed to improve the sanitary condition.