Rezaei Farzaneh, Xing Defeng, Wagner Rachel, Regan John M, Richard Tom L, Logan Bruce E
Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, 16802, USA.
Appl Environ Microbiol. 2009 Jun;75(11):3673-8. doi: 10.1128/AEM.02600-08. Epub 2009 Apr 3.
Electricity can be directly generated by bacteria in microbial fuel cells (MFCs) from many different biodegradable substrates. When cellulose is used as the substrate, electricity generation requires a microbial community with both cellulolytic and exoelectrogenic activities. Cellulose degradation with electricity production by a pure culture has not been previously demonstrated without addition of an exogenous mediator. Using a specially designed U-tube MFC, we enriched a consortium of exoelectrogenic bacteria capable of using cellulose as the sole electron donor. After 19 dilution-to-extinction serial transfers of the consortium, 16S rRNA gene-based community analysis using denaturing gradient gel electrophoresis and band sequencing revealed that the dominant bacterium was Enterobacter cloacae. An isolate designated E. cloacae FR from the enrichment was found to be 100% identical to E. cloacae ATCC 13047(T) based on a partial 16S rRNA sequence. In polarization tests using the U-tube MFC and cellulose as a substrate, strain FR produced 4.9 +/- 0.01 mW/m(2), compared to 5.4 +/- 0.3 mW/m(2) for strain ATCC 13047(T). These results demonstrate for the first time that it is possible to generate electricity from cellulose using a single bacterial strain without exogenous mediators.
在微生物燃料电池（MFC）中，细菌可利用多种不同的可生物降解底物直接产生电能。当以纤维素作为底物时，发电需要一个同时具有纤维素分解活性和产电活性的微生物群落。此前，在不添加外源介体的情况下，尚未证明纯培养物能在降解纤维素的同时产生电能。我们使用专门设计的U型管MFC，富集了一个能够将纤维素作为唯一电子供体的产电细菌联合体。对该联合体进行19次稀释至灭绝的连续传代后，利用变性梯度凝胶电泳和条带测序对基于16S rRNA基因的群落进行分析，结果显示优势菌为阴沟肠杆菌。基于部分16S rRNA序列，从富集培养物中分离得到的一株阴沟肠杆菌FR与阴沟肠杆菌ATCC 13047(T)的序列100%相同。在以U型管MFC和纤维素为底物的极化测试中，菌株FR的产电功率为4.9±0.01 mW/m²，而菌株ATCC 13047(T)的产电功率为5.4±0.3 mW/m²。这些结果首次证明，不使用外源介体，单一菌株利用纤维素发电是可行的。
