A microbial biosensor for trimethylamine using Pseudomonas aminovorans cells

A biosensor system based on the difference in the oxygen uptake response of two microbial electrodes was developed to monitor trimethylamine (TMA). The first electrode, constructed using Pseudomonas aminovorans grown on TMA, was sensitive to TMA, trimethylamine N-oxide (TMAO), dimethylamine (DMA) and monomethylamine (MMA). The second electrode responding to TMAO, DMA and MMA was prepared using Ps. aminovorans grown on TMAO. The difference in oxygen uptake was linearly related to the TMA concentration in the range of 5-26 μm. The minimum detectable level was 2·6 μm and the relative standard deviation was determined to be 14% for 16 repeated analyses. When operated and stored at 30°C, the response of the system was stable for only 2 days. However, when the biosensor system was operated at 30°C but stored overnight at 4°C, the system was stable up to 20 days. The biosensor system was applicable for the determination of TMA in fish tissue extracts and the results compared well with those determined by HPLC.