一株产电菌嗜根考克氏菌(Kocuria rhizophila)的分离及其产电性能优化

本研究以天津泰达污水处理厂污泥浓缩间的污泥为接种物,启动并运行了微生物燃料电池(MFCs).从富集的阳极生物膜上分离得到了一株纯培养的微生物菌种,命名为P2-A-5.研究发现,菌株P2-A-5的16S rDNA序列与菌株Kocuria rhizophila DC2201具有100%的同源性,结合该菌的形态特征和生理生化实验,将其归属为嗜根考克氏菌(Kocuria rhizophila).通过化学剂处理、底物种类和浓度的优化,进一步提高其在微生物燃料电池中的产电性能.结果表明,菌株K.rhizophila P2-A-5经0.5 mg·L-1溶菌酶处理45 min后,接种到以2.0 g·L-1海藻糖为底物的阳极液中运行MFCs,其功率密度达到314.8 m W·m-2,比优化前(74.9 m W·m-2)提高了320.3%.这是首次对K.rhizophila种内微生物产电性能及其在微生物燃料电池中应用的报道,其成果对于丰富产电微生物的多样性,挖掘更多具有高电化学活性的微生物菌种,提高其产电性能具有重要的理论意义.

Isolation of an exoelectrogen Kocuria rhizophila from the anodic biofilm and optimization of its power generation

An electrogenic bacterium (designated as P2-A-5) was isolated from the anodic biofilm of microbial fuel cells (MFCs) inoculated with sludge from a sewage treatment plant. The 16S rDNA sequence of P2-A-5 had 100% similarity with strain Kocuria rhizophila DC2201. Combined with its morphological, physiological and biochemical properties, strain P2-A-5 was identified as Kocuria rhizophila. The power generation performance of the strain P2-A-5 was further improved by cells modification with chemical reagents, and optimizing the type and concentration of the substrates. The results showed that strain P2-A-5 treated with 0.5 mg·L^-1 lysozyme for 45 min achieved the highest power density of 314.8 mW·m^-2 with 2.0 g·L^-1 trehalose as the substrate, which was 320.3% higher than the original level (74.9 mW·m^-2). It is the first time that the strain affiliated to K. rhizophila shows electrochemical activity when applying in MFCs. The research is of important guidance for enriching the diversity of electricigens, discovering more microbes with high electrochemical activity and improving the electricity production performance.