铜绿假单胞菌存活时间延长可提高生物燃料电池的产电量

Survival elongation of Pseudomonas aeruginosa improves power output of microbial fuel cells

摘要:

铜绿假单胞菌产生的次生代谢产物吩嗪化合物具有电子传递作用，可用于构建微生物燃料电池。如何通过改进微生物自身性质来提升微生物燃料电池产电量是研究的热点与难点之一。本文以铜绿假单胞菌SJTD-1和其敲除突变株SJTD-1 (ΔmvaT) 为对象，研究了以其搭建的微生物燃料电池的放电过程，分析了影响其放电量的主要因素。结果显示，假单胞菌产生的吩嗪化合物和发酵系统中细菌的活性与存活数量均会直接影响燃料电池的产电量。敲除突变株SJTD-1 (ΔmvaT) 可产生较多的吩嗪化合物，在生物燃料电池系统可持续放电超过160 h，产生2.32 J的总电量；而野生菌株SJTD-1仅能放电90 h，产生1.30 J的总电量。细胞生长分析结果进一步显示，与野生菌株相比，突变菌株SJTD-1 (ΔmvaT) 在发酵过程中维持了较长的稳定期生长，细胞存活时间更长，放电时间更持久。因此，铜绿假单胞菌存活时间延长，可增加其在微生物燃料电池中的放电时间，从而提升微生物燃料电池的总产电量。本研究可为通过工程菌株改造来提升微生物燃料电池总产电量的研究提供思路，有利于推进微生物燃料电池的实际应用。

Abstract:

The secondary metabolites, phenazine products, produced by Pseudomonas aeruginosa can mediate the electrons transfer in microbial fuel cells (MFCs). How increase the total electricity production in MFCs by improving the characteristics of Pseudomonas aeruginosa is one of research hot spots and problems. In this study, P. aeruginosa strain SJTD-1 and its knockout mutant strain SJTD-1 (ΔmvaT) were used to construct MFCs, and the discharge processes of the two MFCs were analyzed to determine the key factors to electricity yields. Results indicated that not only phenazine but also the viable cells in the fermentation broth were essential for the discharge of MFCs. The mutant strain SJTD-1 (ΔmvaT) could produce more phenazine products and continue discharging over 160 hours in MFCs, more than that of the wild-type SJTD-1 strain (90 hours discharging time). The total electricity generated by SJTD-1 (ΔmvaT) strain could achieve 2.32 J in the fermentation process, much higher than the total 1.30 J electricity of the wild-type SJTD-1 strain. Further cell growth analysis showed that the mutant strain SJTD-1 (ΔmvaT) could keep a longer stationary period, survive much longer in MFCs and therefore, discharge more electron than those of the wild-type SJTD-1 strain. Therefore, the cell survival elongation of P. aeruginosa in MFCs could enhance its discharging time and improve the overall energy yield. This work could give a clue to improve the characteristics of MFCs using genetic engineering strain, and could promote related application studies on MFCs.