Gesellschaft zur Förderung von Medizin-,
Bio- und Umwelttechnologien e. V.

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Substrate screening with Bio-Activity-Sensors

The Continuous-Flow Analysis system can be used for the characterization of physiological metabolisms of microorganisms. On this principle „Bio-Activity-Sensor“ (BAS), microorganism cells, which are still in their natural physiological state, are tested with a sequence of agents. A basic example is the application of the substrate screening. The cells (aerobe bacteriae, isolates, sludges …) are taken directly from the culture and installed on a porous membrane in an oxygen measuring cell.

They are permanently flowing with an oxygenated carrier. The substances (e.g. organic pollutants from remedial actions) and a good utizable reference substance (e.g. acetate glucose) are injected in this flow. If the substances are metabolized, then the measurement shows negative peaks (oxygen consumption).

The peaks are compared with the reference and a qualitative estimation is possible within a few minutes.

Measurement with Microalgae

Phototrophic cells such as microalgae and cyanobacteriae have a great potential as a resource and energy supplier and can be used well for diverse sensory measurement. Microalgae are ideal receptor components for:

  • monitoring the vitality of cultures
  • analyzing the water qualities
  • screening of photosynthese inhibitors
  • correlation the cell density by algae growth

Luminescence characteristics and light-induced oxygen release are used as measured variable. Prototypes were developed in cooperation with ECH GmbH.

Inhibitory effects occur when microalgae get in contact with toxic chemicals. For example, algae show an increased after flow (phosphorescence) for several seconds. The light energy is not dissipated goal-oriented in the electron transport chain by cell damage, but distributed as a light emission.

The Flow-Injection-Analysis (FIA) - measuring station can be used to detect the oxygen production of membrane immobilized microalgae cells. This is measurable because of the increasing oxygen concentration in close proximity to the algae immobilisate in a flow-through measuring cell as a result of the exposure to light. Damaged algae cells (e.g. influences of toxic substances) show a significant smaller oxygen signal.