Université de Toulouse, UPS, INP, Laboratoire d’Ecologie Fonctionnelle, 118 Route de Narbonne, F-31062 Toulouse, France.
Appl Environ Microbiol. 2011 Aug;77(15):5394-401. doi: 10.1128/AEM.00500-11. Epub 2011 Jun 3.
Electroactivity is a property of microorganisms assembled in biofilms that has been highlighted in a variety of environments. This characteristic was assessed for phototrophic river biofilms at the community scale and at the bacterial population scale. At the community scale, electroactivity was evaluated on stainless steel and copper alloy coupons used both as biofilm colonization supports and as working electrodes. At the population scale, the ability of environmental bacterial strains to catalyze oxygen reduction was assessed by cyclic voltammetry. Our data demonstrate that phototrophic river biofilm development on the electrodes, measured by dry mass and chlorophyll a content, resulted in significant increases of the recorded potentials, with potentials of up to +120 mV/saturated calomel electrode (SCE) on stainless steel electrodes and +60 mV/SCE on copper electrodes. Thirty-two bacterial strains isolated from natural phototrophic river biofilms were tested by cyclic voltammetry. Twenty-five were able to catalyze oxygen reduction, with shifts of potential ranging from 0.06 to 0.23 V, cathodic peak potentials ranging from -0.36 to -0.76 V/SCE, and peak amplitudes ranging from -9.5 to -19.4 μA. These isolates were diversified phylogenetically (Actinobacteria, Firmicutes, Bacteroidetes, and Alpha-, Beta-, and Gammaproteobacteria) and exhibited various phenotypic properties (Gram stain, oxidase, and catalase characteristics). These data suggest that phototrophic river biofilm communities and/or most of their constitutive bacterial populations present the ability to promote electronic exchange with a metallic electrode, supporting the following possibilities: (i) development of electrochemistry-based sensors allowing in situ phototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions.
电活性是微生物在生物膜中组装的一种特性，已在多种环境中得到强调。本研究在群落和细菌种群尺度上评估了好氧河流生物膜的电活性。在群落尺度上，使用不锈钢和铜合金作为生物膜定植的支持物和工作电极来评估电活性。在种群尺度上，通过循环伏安法评估环境细菌菌株催化氧气还原的能力。我们的数据表明，通过干质量和叶绿素 a 含量测量，电极上好氧河流生物膜的发展导致记录的电位显著增加，不锈钢电极上的电位高达+120 mV/饱和甘汞电极（SCE），铜电极上的电位高达+60 mV/SCE。通过循环伏安法测试了从天然好氧河流生物膜中分离的 32 株细菌。其中 25 株能够催化氧气还原，电位偏移范围为 0.06 至 0.23 V，阴极峰电位范围为-0.36 至-0.76 V/SCE，峰幅度范围为-9.5 至-19.4 μA。这些分离株在系统发育上多样化（放线菌、厚壁菌门、拟杆菌门和α-、β-和γ-变形菌门），并表现出各种表型特性（革兰氏染色、氧化酶和过氧化氢酶特性）。这些数据表明，好氧河流生物膜群落及其组成细菌种群具有促进与金属电极进行电子交换的能力，支持以下可能性：（i）开发基于电化学的传感器，允许原位好氧河流生物膜检测；（ii）在贫营养条件下生产微生物燃料电池接种物。
