Monitoring Biodegradable Substances with High-Molecular Content with a Microbial Sensor

Microbial sensors utilizing microorganisms that are in immediate contact with a transducer, which converts the biochemical signal into a quantifiable electrical response signal, are used for sensitive determinations of a large spectrum of substances, especially in the field of environmental monitoring. A commercially available BOD sensor for the detection of biodegradable pollution was employed in the marshes of Mai Po WWF Nature Reserve area in Hong Kong. The sensor response was at first very low due to the presence of substances with high molecular content compared with the result of the standard 5-day BOD test. Therefore, pretreatment of the sample was conducted and good correlation between the result of the standard method and the BOD sensor was found.