The voltage and the power production of two gram negative and two gram positive bacteria in four
identical continuous flow microbial fuel cells combined with biological wastewater treatment units were evaluated and
compared in the present study. Each microbial fuel cell and biological treatment unit was operated at four different flow
rates and four different external load resistances. The results show that overall removal efficiency of chemical oxygen
demand for all four systems can reach more than 85.5%. Each pure culture has different power generation performance
that can be affected by some factors, such as wastewater characteristics, influent flow rate and hydraulic retention time
of reactor. Good linear relationships between the flow rate and the potential and between the flow rate and the power
density on four pure cultures at different external load resistances were found.
Comamonas testosteroni
has better
power generation performance than
Arthrobacter polychromogenes
, especially at higher flow rate. Although
Pseudomonas putida
also showed higher power generation than
Corynebacterium glutamicum
, the difference was not statistically significant. It seems that gram negative bacteria could display higher power generation than gram positive bacteria at higher flow rate. However, more evidence is required to provide stronger proof for the difference of power generation
between gram negative and gram positive bacteria.