Abstract: A system and device for filtering fluids using graphene oxide (GO) is provided. GO-based filters may be used for the efficient removal of microorganisms from organic and aqueous liquids and may be used to prevent fuel biodeterioration. Functionalization of graphene oxide with reactive oxygen functional groups provides physical properties to the GO including high solubility in polar solvents, good colloidal properties, low production costs, low toxicity, and a large surface area which can be decorated with antimicrobial agents including nanosilver. GO may be used as a filtration media for efficient removal of bacteria and to remove small amounts of water from hydrocarbon fuels. The GO filter media may be made of a plurality of GO particles, a structural core coated with GO, a non-porous structural membrane coated with GO, or a filtering membrane coated with GO. A method for sampling impurities found in an environmental sample is also provided.

Abstract: The invention provides a system of heavy metal sequestration by bacteria. The bacteria expresses the ppk, mt, and/or ?-galactosidase (lacZ) genes and can tolerate at least 25 ?M mercury, 1,000 ?M zinc, 250 ?M cadmium, and 3,000 ?M Pb. The system allows for facile determination of the presence of heavy metal contaminants in a liquid and the facile collection of the bacteria that has sequestered large amounts of heavy metal. Further provided is a system of gene expression in bacteria that comprises phage and plastid gene expression elements and delivers a particularly high level of protein expression and heavy metal resistance.