DEVELOPMENT OF CULTURE-BASED BIOLOGICAL MICROELECTRO- MECHANICAL SYSTEMS (BioMEMS) FOR MEASURING NOCARDIOFORMS IN WASTEWATER TREATMENT

One benefit of the advancement of microbial screening techniques is improved detection of the microorganisms that are responsible for foaming in activated sludge wastewater treatment plants. Molecular-biology based techniques are useful in identifying these organisms since they are sensitive, specific, and rapid. However, these techniques lack quantitative power, the ability to distinguish between living and dead organisms, and do not generate cultures that may be assayed for phenotypic traits. These drawbacks have caused culture-based methods to remain the “gold standard” for screening for microorganisms in environmental samples. Yet traditional culture-based methods lack the sensitivity and convenient turn-around time of molecular biology-based techniques. In a desire to improve culture-based methods for monitoring specific microbial populations in environmental samples, our team is developing a novel approach of detection by employing BioMEMS (Biological Micro-Electro- Mechanical Systems) technology to miniaturize culture-based methods for identification, enumeration, and characterization of microorganisms in environmental samples. Our preliminary biochip is based on the principle of selectively isolating mycobacteria and nocardioforms from environmental samples using paraffin coated microscope slides (reviewed in Ollar, 1999) thus exploiting the paraffinophilic (i.e., wax loving) nature of these microorganisms. Paraffinophilicity is considered to be a conserved trait not possessed by organisms other than the superfamily mycolata, which includes the nocardioforms. Using our first generation device we determined that selective isolation of target organisms can be completed in as little as five minutes, while non-target organisms do not bind to the surface of the device. Initial calibration of the biochip indicates binding occurs in a manner consistent with the surface adsorption theory of the Langmuir isotherm. By developing this rapid, simple, and specific detection method for nocardioforms in wastewater treatment systems, plant operators will have a tool that will save money, time, and resources through diagnosing the causative microorganism of foaming.