• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.811-817
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• 2013

The present study dealt with the isolation, identification and enzyme characterization of potential luminous bacteria from water, sediment, squid, and cuttle fish samples of the Karaikal coast, Bay of Bengal, India during the study period September 2007 - August 2008. Bioluminescent strains were screened in SWC agar and identified using biochemical tests. As Shewanella henadai was found to be the most common and abundant species with maximum light emission [69,702,240 photons per second (pps)], the optimum ranges of various physicochemical parameters that enhance the luciferase activity in Shewanella hanedai were worked out. The maximum luciferase activity was observed at the temperature of $25^{\circ}C$ (69,674,387 pps), pH of 8.0 (70,523,671 pps), salinity of 20 ppt (71,674,387 pps), incubation period of 16 h (69,895,714 pps), 4% peptone (70,895,152 pps) as nitrogen source, 0.9% glycerol (71,625,196 pps), and the ionic supplements of 0.3% $CaCO_3$ (73,991,591 pps), 0.3% $K_2HPO_4$ (73,919,915 pps), and 0.2% $MgSO_4$ (72,161,155 pps). Shewanella hanedai was cultured at optimum ranges for luciferase enzyme characterization. From the centrifuged supernatant, the proteins were precipitated with 60% ammonium sulfate, dialyzed, and purified using anion-exchange chromatography, and then luciferase was eluted with 500 mM phosphate of pH 7.0. The purified luciferase enzyme was subjected to SDS-PAGE and the molecular mass was determined as 78 kDa.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.547-555
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• 2018

In addition to North America and Europe, Korea is also responding to the toxic damage caused by the production and distribution of chemicals. Methods for assessing bio-toxicity of harmful substances have been widely introduced, but it is required of quantitative and speedy information for modeling. For 6 heavy metals, as zinc, copper, chrome, cadmium, mercury and lead, bio-toxicity assessment and kinetics model were constructed using Vibrio fischeri which is widely used luminous bacteria. The degree of luminescence activity and the toxicity of heavy metals were relative limunescence unit, RLU measured as by using a photomultiplier embedded device. The toxicity was assessed by the concentration levels giving under 20% lethality and lethal concentration, $EC_{50}$. In the results, the toxicity order were followed from mercury, lead, copper, chrome, zinc and cadmium. $EC_{{50},{\infty}}$ obtained by trends of $EC_{50}$ by time follows had highly linear agreement with main parameters of bio-toxicity modelling. The average error rates of the reproduced lethality obtained from DAM and TDM model on the basis of body residue, were 10.2% for mercury, lead, copper, chrome and 20.0 for the all 6 methals.

• Microbiology and Biotechnology Letters
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• v.12 no.4
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• pp.265-270
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• 1984

Luminous marine bacteria which have ability toproduce pyruvic acid were isolated from fresh fishes. Among them, newly isolated bacterium BL-1980 having the highest ability to produce pyruvic acid was selected and identified as Beneckea sp. Optimal conditions for the production of pyruvic acid from glucose by the bacterium BL-1980 were investigated. At the optimal conditions, 10.6g/L of pyruvic acid was produced at the conversion ratio of 35.33%.

• Korean Journal of Microbiology
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• v.34 no.3
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• pp.154-161
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• 1998

To investigate whether the introduced genetic marker is useful to detect the survivalship and activity of the natural bacteria under the stressed conditions, one Gram-negative isolate, KP964 was transformed to the luminous phenotype by transferring luxAB gene. Under the starvation-stress this luminous bacterial culturability (determined by colony-forming-units [CFU] on agar plate) decreased rapidly below the detection limit by 37 days, while its total cell number (determined by AODC) remained almost the same as its initial inocular size. At that time period, the viable cell number was estimated to be 1400 times higher than its CFU number. The bioiuminescence (determined by relative light units [RLU]) produced under the same condition was also monitored and found to decrease more rapidly than the culturability by 5-fold. Under the other stresses, e.g., osmotic shocks, acid shock, and exposure to toxic chemicals, this bacterial strain did not show the reliable correlation between CFU and RLU. These results might not suggest the direct estimation of bioiuminescence from the stressed bacteria be an index of both the survivalship and its activity. However, when the stressed bacterial cells were incubated under the favorable condition by relieving from the existing stress, the potential bioiuminescence (the lag periods before the increase of bioiuminescence, the increase rates of bioiuminescence, and the maximal levels of bioiuminescence) was shown to be highly dependent upon the strengths of the stresses exposed to the bacterial cells. Therefore, analysis of the potential bioiuminescence from the stressed bacteria revealed good relationships with survival as well as activity.