Effect of sludge age on microbial consortia developed in MFCs

Abstract

BACKGROUND This work is focused on the assessment of the performance of mini‐scale air‐breathing microbial fuel cells (MFCs), by monitoring the evolution of the bio‐electrogenic activity for a period of 40 days and by comparing the microorganisms populations developed in each of the MFCs after this period. RESULTS Five MFCs were operated at sludge ages ranging from 1.4 to 10.0 days. Results showed the superb performance of the MFC operating under a sludge age of 2.5 days. Desulfuromonas, Syntrophothermus, Solitalea, Acholeplasma, Propionicimonas, Desulfobacula and Sphaerochaeta are proposed as potentially responsible for the bio‐electrogenic activity. CONCLUSIONS Microbial population analysis through Illumina amplicon sequencing demonstrated that despite all MFCs being seeded with the same mixed culture inoculum, the biological cultures developed in the suspension and the biofilm are completely different and depend strongly on sludge age. © 2017 Society of Chemical Industry

Influence of Sludge Age on the Performance of a Cyclically Fed Microbial Fuel Cell Using Glycerol from Biodiesel

“…As observed in Figures a and b, any modification in SA reduces the CCV when compared with the CCV reference value at a SA of 24 d which was the reference used in our previous study of the influence of HRT . The important influence of SA on the electrochemical performance has been reported in the literature and is based on the evidence that SA directly influences the composition of the microbial consortia in the anodic compartment . Based on this argument, the EGMs develop more favorably with the application of a SA of 24 d. In this case, a large amount of redox mediator (mediated electron transfer, MET) may be produced by the suspended EGM.…”

“…This allows for a faster development rate and a higher value for VSS. The differences in the operational conditions (cell design, operation mode, substrate concentration, start‐up conditions, substrate type and the sequence chosen for the SA study) can explain the difference between our results and other results found in the literature . Another interesting feature can be derived from the fact that the maximum concentration of VSS (microorganisms) is achieved at shorter SAs compared to the maximum CCV.…”

“…The best values were attained for an SA of 24 d, which agrees with the overall polarization curves. This SA represents the most favorable condition for the development and activity of the EGM, whose most efficient activity requires relatively long SAs . In the case of cathodic performance, the impact of the SA is very limited.…”

“…Another parameter with a marked influence on the performance of an MFC is the sludge age (SA). This was demonstrated by the research group of M. A. Rodrigo . One important aspect that they highlighted in their studies was that a change in the SA directly affected the solids suspended in the anodic compartment, but not the microorganisms attached to the anode forming the biofilm .…”

“…This was demonstrated by the research group of M. A. Rodrigo . One important aspect that they highlighted in their studies was that a change in the SA directly affected the solids suspended in the anodic compartment, but not the microorganisms attached to the anode forming the biofilm . Nevertheless, one can expect that the surrounding conditions may affect the biofilm characteristics based on an equilibrium established between the biofilm and the surroundings.…”