Influence of environmental factors on electricity generation performance of electricity-producing bacteria from oily sludge microbial fuel cells

Electricity-generating bacteria are used as the biocatalysts of microbial fuel cells (MFCs). The power-generating properties of electricity-generating bacteria play an important role in organic matter degradation and electricity generation of MFCs. However, there are few electricity-producing bacteria isolated from the anode bio-film of microbial fuel cells containing oily sludge. More importantly, the adaptability of nitrogen-to-phosphorus ratio, temperature and pH of the electricity-generating bacteria were adjusted by controlled variable method. The results of this study showed that the isolated electricity-producing bacteria (Citrobacter freundii) with a rod-shaped cell, wrinkled surface, about 0.5-1.0 mu m in length. The optimal nitrogen-to-phosphorus ratio, temperature and pH of MFCs are 5.67:1, 25 degrees C, and pH = 7.5, Its maximum voltage and power density was up to 143.01 mV and 65 mW center dot m(-3), respectively. Furthermore, the growth rate of the electricity-producing bacteria is the highest. This lays the foundation for inoculating electricity-generating bacteria into oily sludge MFCs to improve the oil removal and power generation performance.