Electroactivity of weak electricigen Bacillus subtilis biofilms in solution containing deep eutectic solvent components

Neda Eghtesadi, Kayode Olaifa, Filippo Maria Perna, Vito Capriati, Massimo Trotta, Obinna Ajunwa, Enrico Marsili

Research output: Journal PublicationArticlepeer-review

5 Citations (Scopus)


Bacillus subtilis is a Gram-positive, spore-forming bacterium with a versatile and adaptable metabolism, which makes it a viable cell factory for microbial production. Electroactivity has recently been identified as a cellular characteristic linked with the metabolic activity of B. subtilis. The enhancement of B. subtilis electroactivity can positively enhance bioproduction of high-added value metabolites under electrofermentative conditions. Here, we explored the use of deep eutectic solvents (DESs) and DES components as biocompatible nutrient additives for enhancing electroactivity of B. subtilis. The strongest electroactivity was obtained in an aqueous choline chloride: glycerol (1:2 mol mol−1) eutectic mixture. At low concentration (50–500 mM), this mixture induced a pseudo-diauxic increase in planktonic growth and increased biofilm formation, likely due to a nutritional and osmoprotectant effect. Similarities in electroactivity enhancements of choline chloride-based eutectic mixtures and quinone redox metabolism in B. subtilis were detected using high performance liquid chromatography and differential pulse voltammetry. Results show that choline chloride-based aqueous eutectic mixtures can enhance biomass and productivity in biofilm-based electrofermentation. However, the specific mechanism needs to be fully elucidated.

Original languageEnglish
Article number108207
Publication statusPublished - Oct 2022
Externally publishedYes


  • Bacillus subtilis
  • Choline chloride
  • Deep eutectic solvents
  • Electroactivity
  • Glycerol

ASJC Scopus subject areas

  • Biophysics
  • Physical and Theoretical Chemistry
  • Electrochemistry


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