  The zymase activity of the yeast Saccharomyces Cerevisiae is sensitive to
environmental parameters and is therefore used as a microbiological sensor for
water quality assessment, ecotoxicological characterization or environmental
monitoring. Comparing to bacterial bioluminescence approach, this method has no
toxicity, excludes usage of genetically modified microorganisms, and enables
low-cost express analysis. This work focuses on measuring the yeast
fermentation dynamics based on multichannel pressure sensing and
electrochemical impedance spectroscopy (EIS). Measurement results are compared
with each other in terms of accuracy, reproducibility and ease of use in the
field conditions. It has been shown that EIS provides more information about
ionic dynamics of metabolic processes and requires less complex measurements.
The conducted experiments demonstrated the sensitivity of this approach for
assessing biophotonic phenomena, non-chemical water treatments and impact of
environmental stressors.
