Sprayable biofilm – Agarose hydrogels as 3D matrix for enhanced productivity in bioelectrochemical systems

Microbe–Anode Interactions: Comparing the impact of genetic and material engineering approaches to improve the performance of microbial electrochemical systems (MES)

“…However, no negative control was performed, so no improvement factor can be calculated for this study. Consistent with this embedding into conductive polymers, Knoll, Fuderer, and Gescher ( 2022 ) used agarose hydrogels containing riboflavin‐functionalized carbon nanofibres, which resulted in a 9‐fold increase in mean current density and demonstrated that it was even possible to spray this biomaterial onto the electrode surface. This was the first report on spraying biofilm material, and the latter could facilitate the application of biocomposites in industrial processes.…”

“…For example, a conceivable scenario could be that individual cells modified to perform as current collectors by in situ synthesis of FeS nanoparticles (Yu et al, 2020 ) are embedded in a PEDOT:PSS hydrogel (Zajdel et al, 2018 ). In another, scenario cells coated with polypyrrole and polydopamine (Wang, Pan, et al, 2021 ) are embedded in an agarose hydrogel and sprayed (Knoll et al, 2022 ) onto a carbon paper electrode modified with rGO and silver nanoparticles (Cao et al, 2021 ). In this way, new ecological niches are colonized by cells with improved adhesion properties, and the overall performance could exceed the individual improvements.…”

Microbial Electrosynthesis Using 3D Bioprinting of Sporomusa ovata on Copper, Stainless-Steel, and Titanium Cathodes for CO2 Reduction

“…That being said, increasing the amount of microbial cells directly on the electrode has shown significant increase in production; for example, the use of silicon nanowire arrays to entrap the cells [18], electrode modification to make it more biocompatible [28], and also the use of 3D-bioprinted biofilms [16] are the ways to increase cell density in cathode biofilm. For 3D-bioprinting biofilms, a concentrated cell suspension is mixed with a cross-linkable hydrogel and printed directly on the cathode, forming a dense biofilm in approximately a third of the normal time required (less than two days, compared to a week typically required) [16,29]. Bioprinted biofilms, for example, allow for significant biofilm growth, even when using microbes that do not naturally form thick biofilms, such as S. ovata, and has been shown to greatly increase acetate production in MES with an average acetate production of 47 ± 5.1 g/m 2 /d (0.31 ± 0.55 g/L/d) [16].…”