Advances in Biochips

The aim of this study was to create a laboratory model of an amperometric microbial biosensor for maltose quantification in the presence and absence of starch and to estimate the use of the model in the study of maltase activity of the culture-receptor. The biosensor for maltose was developed on the basis of a Clark-type oxygen electrode, coupled with a bioreceptor, which contained bacterial cells immobilized on the membrane. The determination of maltose concentration was based on measuring the rate of electrode current change in response to addition of the analyte. The detection limit of the biosensor was 1 µM maltose, a linear interval of standard curve was observed from 14 µM up to 1.9 mM of maltose. The microbial biosensor demonstrated good sensitivity to maltose, 36.02 nА (M·s)^-1. Combination of bioreceptors on the basis of fungus and bacterium allowed of using the biosensor for quantification of maltose in the presence of starch. Changes in metabolism of the culture-receptor had an effect on the biosensor response. It indicated that the developed model was a tool of simple construction and easy-to-use in the study of maltase activity of the immobilized culture-receptor.