title: Development of immobilized biophotonic beads consisting of Photobacterium leiognathi for the detection of heavy metals and pesticide.
abstract: The present communication deals with construction of immobilized robust biophotonic bead using P. leiognathi, a marine luminescent bacterium for their possible application in monitoring of environmental toxicants. Immobilization efficiency of agar, carrageenan and sodium alginate was evaluated separately in terms of luminescence response and was recorded as 30.3, 77.4 or 99.5%, respectively. Under optimized storage conditions, the luminescent response of P. leiognathi in the immobilized state was studied over a period of 30 days. These biophotonic beads were further used as a rapid and reliable optical biosensing tool for the detection of heavy metals [Hg(II), As(V) or Cd(II)] and pesticide [2,4-dichlorophenoxyacetic acid (2,4-D)] in water systems. The concentration range for the detection of Hg(II), As(V), Cd(II) and 2,4-D was 2-32ppm, 4-128ppm, 16-512ppm and 100-600ppm, respectively, while corresponding sensitivity threshold was 2.0ppm, 4.0ppm, 16.0ppm and 100ppm. A comparison of inhibition constant (K(d)) (or EC(20)) values indicated that the sensitivity thresholds rank as Hg(II)>As(V)>Cd(II)>2,4-D. Moreover, the time taken for the detection of heavy metals and pesticide was less than 30min. Using the bioluminescence inhibition method, the concentration of heavy metals and pesticide could be predicted.
authors.affiliation: Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute, Mysore 570020, India.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Ranjan
authors.forename: Navin K
authors.initials: NK
authors.lastname: Rastogi
authors.forename: M S
authors.initials: MS
authors.lastname: Thakur
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis; D001151:Arsenic / Q000032:analysis*; D015374:Biosensing Techniques; D002104:Cadmium / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D008163:Luminescent Measurements; D008628:Mercury / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D010776:Photobacterium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical; D002104:Cadmium; D015084:2,4-Dichlorophenoxyacetic Acid; D008628:Mercury; D001151:Arsenic