Novel bioelectrodes based on polysaccharide modified gold surfaces and electrochemically active Lactobacillus rhamnosus GG biofilms.

Abstract Lactobacillus rhamnosus GG is an environmentally and human-friendly bacteria that can be found in probiotics. However, it is incapable of forming a biofilm on metal surfaces, what limits the possibility of using it in bioelectrochemical systems (BESs) as promising and green alternatives. Hence, we propose a simple and cost-effective modification of metal surface with cationic dextran derivative (DEX-G) by using the electrostatically driven self-assembly procedure resulting in the formation of a polymeric monolayer. Modification of metal electrodes was confirmed by using infrared spectroscopy (IR) and atomic force microscopy (AFM). Synthesized metal/polycation electrodes provided a bioactive environment for L. rhamnosus GG enhancing its proliferation and formation of the biofilm as confirmed by SEM imaging. Moreover, using cyclic voltammetry (CV) and chronoamperometry measurements, it was proven that metal/polycation/ L. rhamnosus bioelectrodes are electrochemically active in the glucose-rich medium. The electrochemical activity of fabricated bioanodes allows to consider them for their potential use in the bioelectrochemical systems. Graphical abstract Image 1 Highlights • Metal surface modification method facilitating the biofilm formation is proposed. • Use of lactic acid bacteria for bioelectrochemical systems is examined. • Cationic dextran coating enhanced bacteria colonization of gold. • The electroactivity of proposed bioanodes was confirmed by cyclic voltammetry. [ABSTRACT FROM AUTHOR]