Evaluating strategies for integrating bacterial cells into a biosensor designed to detect electrophilic toxins

dc.contributor.authorLinares, Katherine Anneen
dc.contributor.committeechairLove, Nancy G.en
dc.contributor.committeememberMeehan, Kathleenen
dc.contributor.committeememberLittle, John C.en
dc.contributor.committeememberLove, Brian J.en
dc.contributor.departmentEnvironmental Engineeringen
dc.date.accessioned2011-08-06T16:06:22Zen
dc.date.adate2004-09-14en
dc.date.available2011-08-06T16:06:22Zen
dc.date.issued2004-08-17en
dc.date.rdate2006-09-14en
dc.date.sdate2004-06-18en
dc.description.abstractTo improve the process stability of wastewater treatment plants, the construction of a whole-cell bacterial biosensor is explored to harness the natural stress response of the bacterial cells. The stress response selected in this work is the glutathione-gated potassium efflux (GGKE) system, which responds to electrophilic stress by effluxing potassium from the interior to the exterior of the cell. Thus, the bulk potassium in solution can be monitored as an indicator of bacterial stress. By utilizing this stress response in a biosensor, the efflux of potassium can be correlated to the stress response of the immobilized culture, providing an early warning system for electrophilic shock. This type of shock is a causative factor in many process upset events in wastewater treatment plants, so the application of the sensor would be an early warning device for such plants. The research conducted here focused on the biological element of the biosensor under development. Three immobilization matrices were explored to determine the cell viability and potassium efflux potential from immobilized cells: a calcium alginate, a photopolymer, and a thermally reversible gel. The calcium alginate was unstable, and dissolved after five days, such that the long-term impact of immobilization on the cells could not be determined in the matrix. The photopolymer resulted in very low actvity and viability of immobilized cellsOf the three matrices tested, indicating that the composition of the polymer was toxic to the cells. Of the matrices tested, the thermally-reversible gel showed the best response for further study, in that the matrix did not inhibit cell activity or potassium efflux.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.otheretd-06182004-005946en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06182004-005946en
dc.identifier.urihttp://hdl.handle.net/10919/10113en
dc.publisherVirginia Techen
dc.relation.haspartthesis_Linares_6-3-04.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectmicrobial stress responseen
dc.subjectbiosensoren
dc.subjectbacterial immobilizationen
dc.subjectpotassium effluxen
dc.titleEvaluating strategies for integrating bacterial cells into a biosensor designed to detect electrophilic toxinsen
dc.typeThesisen
thesis.degree.disciplineEnvironmental Planningen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen
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