Microbial Fuel Cells for Bioenergy and Bioproducts

Effect of Different Operating Conditions on MFC Performance

Dual-chamber microbial fuel cells (MFCs) were established to study the effect of seed sludge, carbon sources, buffering solution and stirring on power generation performance. Scanning electron microscope (SEM) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technologies were used to investigate the spatial distribution characteristics of bacterial community. The results showed that the MFC feeding with lactic acid obtained 0.57V of electromotive force, and 1.57 W/m3 of volumetric power density. It reached 0.62V and 2.07 W/m3 when the carbon source was changed to acetic acid. Compared with anaerobic sludge, aerobic sludge had higher maximum voltage and longer high voltage duration. The stirring and the adding buffer solution improved electricity generation. SEM and DGGE profiles indicated that a large number of bacilli were tightly bound to the anode surface. Microbial community structure on the membrane surface was more similar to suspended sludge than sediment and seed sludge. In conclusion, MFCs perform better with incubating aerobic sludge, feeding acetic acid, adding PBS buffer (50mmol/L) and stirring.

Microbial fuel cells and microbial electrolysis cells for the production of bioelectricity and biomaterials

Today's global energy crisis requires a multifaceted solution. Bioenergy is an important part of the solution. The microbial fuel cell (MFC) technology stands out as an attractive potential technology in bioenergy. MFCs can convert energy stored in organic matter directly into bioelectricity. MFCs can also be operated in the electrolysis mode as microbial electrolysis cells to produce bioproducts such as hydrogen and ethanol. Various wastewaters containing low-grade organic carbons that are otherwise unutilized can be used as feed streams for MFCs. Despite major advances in the past decade, further improvements in MFC power output and cost reduction are needed for MFCs to be practical. This paper analysed MFC operating principles using bioenergetics and bioelectrochemistry. Several major issues were explored to improve the MFC performance. An emphasis was placed on the use of catalytic materials for MFC electrodes. Recent advances in the production of various biomaterials using MFCs were also investigated.