Electroactive biofilms - key characteristics and applications
The behavior of microbial biofilms in relationship to electrodes has been a fascinating field of study for the past decade. The functioning of the biofilm depends on many parameters including electrode potential, surface properties and charge transfer approach. Electrode potential impacts microbial community composition. The electrode surface affects colonization and the establishment of an effective biofilm on short term, rather than affecting community composition. Experiments comparing constant electron flux with discontinuous charge/discharge cycles show that the latter leads to higher productivity of the biofilm. This productivity can be correlated to an apparent increase in cytochrome content. Today, the main application of such biofilms (or in extension planktonic communities interacting with the electrode) appears bioproduction from CO2 or organic substrates. The advantage of such an approach is that the typically anionic products are extracted in situ, towards an anode. In the second part of my presentation I want to focus on how electricity pushes production and extraction processes, already at pilot scale. I will discuss the examples of feed additive productions from thin stillage, and aviation fuel production from syngas.