Enhanced power production from microbial fuel cells with high cell density culture

Abstract

Improvement of power production in a microbial fuel cell (MFC) with a high cell density culture strategy was developed. By using high cell density culture, the voltage output and power density output of the MFC were enhanced about 0.6 and 1.6 times compared to the control, respectively. Further analysis showed that riboflavin concentration in the MFC was dramatically increased from 0.1 mg/L to 1.2 mg/L by high cell density culture. Moreover, the biofilm formation on the anode surface was significantly enhanced by this new strategy. The increased accumulation of electron shuttle (riboflavin) as well as enhanced biofilm formation contributed to the improvement in anodic electrochemical activity and these factors were the underlying mechanism for MFC performance improvement by high cell density culture. This work demonstrated that high cell density culture would be a simple and practical strategy for MFC manipulation.

Extracellular riboflavin induces anaerobic biofilm formation inShewanella oneidensis

“…4). Riboflavin concentrations in batch experiments that have been reported so far vary apparently depending on growth conditions between 30 and 450 nM (17–19). Since we hypothesized that riboflavin could be a quorum sensing molecule that is used by the cells to initiate a cell concentration-dependent physiological response, we quantified the response of the speC promoter on the addition of riboflavin at concentrations between 0 and 100 nM.…”

Improving the extracellular electron transfer of Shewanella oneidensis MR-1 for enhanced bioelectricity production from biomass hydrolysate

“…The cell suspension in electrolyte was added into the anodic chamber, while the cathodic chamber was lled with 50 mM K 3 [Fe(CN) 6 ] and KCl solution. 24 The MFCs were operated at 30 C and pH 7.0 (maintained by the phosphate buffer in the electrolyte) 23 (Fig. S1 †).…”

Addition of Riboflavin-Coupled Magnetic Beads Increases Current Production in Bioelectrochemical Systems via the Increased Formation of Anode-Biofilms

“…Already in Marsili et al (2008) showed that riboflavin accumulates in the supernatant of 4-day-old biofilms in concentrations of 250 to 500 nM (Marsili et al, 2008). Other groups measured only 25 nM flavin in the bulk solution and a change of the BES setup resulted in a different concentration of riboflavin (Velasquez-Orta et al, 2010; Zhai et al, 2016; Lu et al, 2017). Independent of the natural concentration, the artificial addition of riboflavin has stimulatory effects in a BES and this seems to be linearly dependent on the riboflavin concentration in a certain concentration range.…”

“…Independent of the natural concentration, the artificial addition of riboflavin has stimulatory effects in a BES and this seems to be linearly dependent on the riboflavin concentration in a certain concentration range. Consequently, several groups tried to raise the riboflavin concentration either via genetic engineering of MR-1 itself or via co-culturing with other riboflavin producing strains (Zhai et al, 2016; Lu et al, 2017). Still, from an application point of view, although bioelectrochemical systems (BESs) are perfectly suited for continuous biofilm based biotechnological production, the constant stream of fresh media over the biofilm would result in a continuous wash out of flavin compounds.…”