Microbial Biosensors for Selective Detection of Disaccharides

Seven microbial strains were screened for their ability to detect disaccharides as components of Clark-type oxygen biosensors. Sensors responded to varying degrees to maltose, cellobiose, sucrose, and melibiose, but none responded strongly to lactose. Although microbial sensors are relatively nonspecific, it is possible to obtain differential measurements of specific substrates using multiple sensors with different relative specificities. For example, Escherichia coli strain K-802 oxidized maltose but had low activity against sucrose, while Bacillus subtilis strain VKM B-434 responded more strongly to sucrose than maltose. Furthermore, signals from these two sensors were additive for selected samples. Results suggest that a two-component biosensor utilizing these strains could be used for differential detection of sucrose and maltose.