Metabolites produced by Pseudomonas sp enable a Gram-positive bacterium to achieve extracellular electron transfer
Metabolites produced by Pseudomonas sp enable a Gram-positive bacterium to achieve extracellular electron transfer
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DOI：
10.1007/s00253-007-1248-6
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发表时间：
2008-01-01
影响因子：
5
通讯作者：
Rabaey, Korneel
中科院分区：
文献类型：
--
作者：
Pham, The Hai;Boon, Nico;Rabaey, Korneel
先前的研究揭示了在微生物燃料电池（MFC）的微生物群落中的假单胞菌属的丰度。这些细菌可以通过自身产生的吩嗪介体将电子转移到电极。发现用乙酸盐喂养的MFC（其中存在几种假单胞菌属）富含革兰氏阳性细菌，鉴定为短芽孢杆菌属PTH 1。值得注意的是，在其阳极中仅用短芽孢杆菌菌株操作的MFC具有差的发电能力。在用假单胞菌属CMR 12 a（一种产生大量吩嗪-1-甲酰胺（PCN）和生物表面活性剂的菌株）操作的MFC的无细胞阳极上清液替换含有MFC的短芽孢杆菌的阳极水性部分后，发电显著提高。假单胞菌CMR12a_Reg，一种缺乏产生PCN能力的调节突变体的上清液，没有类似的改善效果。纯化的PCN，连同鼠李糖脂作为生物表面活性剂（1毫克L-1），可以明显提高发电短芽孢杆菌属PTH 1，以及使这种细菌氧化乙酸与伴随的还原三价铁，提供针铁矿（FeOOH）。单独添加时，PCN对短芽孢杆菌的电子传递没有明显影响。这项工作表明，假单胞菌产生的代谢产物使革兰氏阳性菌实现胞外电子转移。可能，这种细菌相互作用是MFC阳极电子转移的关键过程，使短芽孢杆菌PTH 1实现其优势。
Previous studies revealed the abundance of Pseudomonas sp. in the microbial community of a microbial fuel cell (MFC). These bacteria can transfer electrons to the electrode via self-produced phenazine-based mediators. A MFC fed with acetate where several Pseudomonas sp. were present was found to be rich in a Gram-positive bacterium, identified as Brevibacillus sp. PTH1. Remarkably, MFCs operated with only the Brevibacillus strain in their anodes had poor electricity generation. Upon replacement of the anodic aqueous part of Brevibacillus containing MFCs with the cell-free anodic supernatants of MFCs operated with Pseudomonas sp. CMR12a, a strain producing considerable amounts of phenazine-1-carboxamide (PCN) and biosurfactants, the electricity generation was improved significantly. Supernatants of Pseudomonas sp. CMR12a_Reg, a regulatory mutant lacking the ability to produce PCN, had no similar improvement effect. Purified PCN, together with rhamnolipids as biosurfactants (1 mg L-1), could clearly improve electricity generation by Brevibacillus sp. PTH1, as well as enable this bacterium to oxidize acetate with concomitant reduction of ferric iron, supplied as goethite (FeOOH). When added alone, PCN had no observable effects on Brevibacillus' electron transfer. This work demonstrates that metabolites produced by Pseudomonas sp. enable Gram-positive bacteria to achieve extracellular electron transfer. Possibly, this bacterial interaction is a key process in the anodic electron transfer of a MFC, enabling Brevibacillus sp. PTH1 to achieve its dominance.