Endogenously enhanced biosurfactant production promotes electricity generation from microbial fuel cells
Tao Zheng, Yu-Shang Xu, Xiao-Yu Yong, Bing Li, Di Yin, Qian-Wen Cheng, Hao-Ran Yuan, Yang-Chun Yong
Biofuels Institute, School of the Environment, Jiangsu University, Zhenjiang 212013, Jiangsu Province, China.
Microbial fuel cell (MFC) is considered as a promising green energy source and energy-saving pollutants treatment technology as it integrates pollutant biodegradation with energy extraction. In this work, a facile approach to enhance endogenous biosurfactant production was developed to improve the electron transfer rate and power output of MFC. By overexpression of rhlA, the key gene responsible for rhamnolipids synthesis, over-production of self-synthesized rhamnolipids from Pseudomonas aeruginosa PAO1 was achieved. Strikingly, the increased rhamnolipids production by rhlA overexpression significantly promoted the extracellular electron transfer of P. aeruginosa by enhancing electron shuttle (pyocyanin) production and increasing bacteria attachment on the anode. As a result, the strain with endogenously enhanced rhamnolipids production delivered 2.5 times higher power density output than that of the parent strain. This work substantiated that the enhancement on endogenous biosurfactant production could be a promising approach for improvement on the electricity output of MFC.
Keywords: Microbial fuel cells; Rhamnolipid; Surfactant; Electron Transfer; Pseudomonas aeruginosa.