CRA--Agrobiology and Pedology Research Centre, Piazza D’Azeglio, 30, 50121 Firenze, Italy.
Appl Microbiol Biotechnol. 2013 Feb;97(3):1299-315. doi: 10.1007/s00253-012-3906-6.
The alteration of the organic matter (OM) and the composition of bacterial community in microbial fuel cells (MFCs) supplied with soil (S) and a composted organic fertilizer (A) was examined at the beginning and at the end of 3 weeks of incubation under current-producing as well as no-current-producing conditions. Denaturing gradient gel electrophoresis revealed a significant alteration of the microbial community structure in MFCs generating electricity as compared with no-current-producing MFCs. The genetic diversity of cultivable bacterial communities was assessed by random amplified polymorphic DNA (RAPD) analysis of 106 bacterial isolates obtained by using both generic and elective media. Sequencing of the 16S rRNA genes of the more representative RAPD groups indicated that over 50.4% of the isolates from MFCs fed with S were Proteobacteria, 25.1% Firmicutes, and 24.5% Actinobacteria, whereas in MFCs supplied with A 100% of the dominant species belonged to γ-Proteobacteria. The chemical analysis performed by fractioning the OM and using thermal analysis showed that the amount of total organic carbon contained in the soluble phase of the electrochemically active chambers significantly decreased as compared to the no-current-producing systems, whereas the OM of the solid phase became more humified and aromatic along with electricity generation, suggesting a significant stimulation of a humification process of the OM. These findings demonstrated that electroactive bacteria are commonly present in aerobic organic substrates such as soil or a fertilizer and that MFCs could represent a powerful tool for exploring the mineralization and humification processes of the soil OM.
在产电流和不产电流条件下，分别对以土壤（S）和堆肥有机肥料（A）为底物的微生物燃料电池（MFC）在 3 周孵育期始末的有机质（OM）变化和细菌群落组成进行了研究。变性梯度凝胶电泳（DGGE）显示，与不产电流的 MFC 相比，产电流的 MFC 中微生物群落结构发生了显著变化。通过对使用通用和选择性培养基获得的 106 个细菌分离株进行随机扩增多态性 DNA（RAPD）分析，评估了可培养细菌群落的遗传多样性。对更具代表性的 RAPD 组的 16S rRNA 基因进行测序表明，S 作为底物的 MFC 中分离出的 50.4%以上的菌株为变形菌门，25.1%为厚壁菌门，24.5%为放线菌门，而 A 作为底物的 MFC 中 100%的优势种属于γ-变形菌门。通过对 OM 进行分级并采用热分析进行化学分析表明，与不产电流系统相比，电化学活性室可溶性相中的总有机碳含量显著减少，而固相 OM 的腐殖化和芳香化程度随着电流的产生而增加，这表明 OM 的腐殖化过程得到了显著的刺激。这些发现表明，电活性细菌通常存在于有氧有机底物（如土壤或肥料）中，并且 MFC 可以作为探索土壤 OM 矿化和腐殖化过程的有力工具。
