AUTHOR=Scarabotti Francesco , Kuchenbuch Anne , Kallies René , Bühler Katja , Harnisch Falk 

TITLE=Toward Real-Time Determination of Yield Coefficients of Early-Stage Electroactive Biofilms by Optical Microscopy

JOURNAL=Frontiers in Energy Research

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.920266

DOI=10.3389/fenrg.2022.920266

ISSN=2296-598X

ABSTRACT=<p>Physiological cellular parameters, such as latency times (<italic>lagt</italic>), cell production rates (CPR), doubling times (<italic>t</italic><sub>d</sub>), relative growth rates (RGR), and yield coefficients (<italic>Y</italic><sub>Ne</sub>), are only known as endpoint measurements for electroactive microorganisms (EAM). Here we show that these can be gained non-invasively and in real-time for early-stage biofilm formation at electrodes using a microfluidic electrochemical flow-cell (EFC) allowing <italic>in vivo</italic> optical microscopy. Parameters obtained for early-stage mixed culture biofilm anodes formed at +150 mV vs. Ag/AgCl sat. KCl have <italic>lagt</italic> of 2.31–4.58 days, CPR of 0.72–1.20 × 10<sup>5</sup> cells h<sup>−1</sup>, <italic>t</italic><sub><italic>d</italic></sub> of 176.54–1838.65 min, RGR of 0.02–0.27 h<sup>−1</sup>, and <italic>Y</italic><sub>Ne</sub> of 5.99–7.94 × 10<sup>12</sup> cells mol<sub>e-</sub><sup>−1</sup>. However, oxygen permeation into the EFC was the main problem that remained unsolved during the study that provides interesting lessons for future improvements.</p>