The chemoautotrophic bacterium Ralstonia eutropha can utilize H2/CO2 for growth under aerobic conditions. While this microbial host has great potential to be engineered to produce desired compounds (beyond polyhydroxybutyrate) directly from CO2, little work has been done to develop genetic part libraries to enable such endeavors.

In this study, we report on a bi-metal organic framework, MOF-919 (Fe–Cu), capable of bifunctional-enzyme mimicking activity with oxidase- and peroxidase-like activities. The catalytic activities were examined by using o-phenylenediamine (OPD) as a chromogenic substrate to study oxidase- and peroxidase-like mimetics. Based on our findings, we developed a simple epinephrine colorimetric biosensor with a broad linear range (1–100 μM) and a low detection limit (0.298 μM). This approach provides evidence for transition metal-based pristine bi-metallic MOFs capable of reproducing both oxidase–peroxidase properties, which could be applied as new nanosensors.

A engineered whole-cell biosensor is developed to generate output signals for the environmental copper analysis.