Piezoelektrischer Schwermetallbiosensor mit Glutathion und Phytochelatin als Biokomponente

Autor: Ebel, Marc Christofer Josef
Přispěvatelé: Hartmeier, Winfried
Jazyk: němčina
Rok vydání: 2005
Předmět:
Zdroj: Aachen : Publikationsserver der RWTH Aachen University III, 111 S. : Ill., graph. Darst. (2005). = Aachen, Techn. Hochsch., Diss., 2005
Popis: Biosensors for the detection of heavy metal show a wide diversity concerning the biological and technical components. Amongst others, metal-inducible promoters, microorganisms, enzymes as well as peptides, which specifically bind heavy metals, can be used as biological components. This work focuses on the specific binding of heavy metals by phytochelatin, which is used to construct a biosensor based on piezoelectrically measured mass changes. To obtain phytochelatin, a packed bed reactor filled with cross- and co-crosslinked phytochelatin-synthase (E.C.: 2.3.2.15) derived from Schizosaccharomyces pombe immobilised in alginate, PVA or sol-gel respectively was set up. An 18fold increase of the specific activity could be achieved by a fractioned ammonium sulphate precipitation. The immobilisation of the enzyme resulted in a low contamination of the fluent phase with enzyme (i.e. low bleeding of the immobilisates), hence there was no need to further purify the produced phytochelatin. In addition, the immobilisation facilitated a lifetime of the packed bed of 4 weeks. Best results were achieved with co-crosslinked, partly purified phytochelatin-synthase immobilised in PVA with a yield of 4,5 mg phytochelatin per litre and day. The phytochelatin produced by these means was immobilised onto a QMB (quartz crystal micro balance) to create a biosensor for heavy metal detection. All applied heavy metals (cadmium, lead, copper and arsenic) could be detected. Other divalent non-metal ions like potassium and magnesium did not have an impact on the measurements. The assembled measuring device facilitated heavy metal detection in a relatively simple "static" as well as in a flow-cell mode. Both modi showed an increase in mass change during the detection of equimolar solutions of arsenic, copper, lead and cadmium respectively (i.e. according to their molar mass). Detection-limits for cadmium using the "static" mode were 2 and 30 µM respectively, using the flow-through technique, limits of 1 and 20 µM were achieved. Applying an imprinted matrix, it was possible to specifically detect cadmium in the presence of other heavy metals. The detection range achieved here was 2 to 20 µM.
Databáze: OpenAIRE