Yeasts Saccharomyces cerevisiae were investigated by scanning electrochemical microscopy (SECM).

Generation-collection mode was applied for SECM-based investigation.

9,10-Phenanthrenequinone was for the first time applied as a lipophilic redox mediator, which was incorporated within cell membrane to facilitate electron transfer.

A two redox mediator based system was designed and adapted in order to evaluate redox activity of yeasts.

The most efficient concentrations of redox mediators suitable for the visualization of redox process of yeast cells were determined.