Microbial composition of a hydropower cooling water system reveals thermophilic bacteria with a possible role in primary biofilm formation

Microfouling, ie biofilm formation on surfaces, can have an economic impact and requires costly maintenance in water-powered energy generation systems. In this study, the microbiota of a cooling system (filter and heat exchanger) in the Irapé hydroelectric power plant in Brazil was examined. The goal was to identify bacteria that could be targeted to more efficiently reduce biofilm formation. Two sampling campaigns were made corresponding to two well-defined seasons of the Brazilian Cerrado biome: the dry (campaign 1) and the wet (campaign 2). Microfouling communities varied considerably over time in samples obtained at different times after the last clearance of the heat exchanger. The thermophilic bacteria <i>Meiothermus</i>, <i>Thermomonas</i> and <i>Symbiobacterium</i> were exclusive and abundant in the microfouling of the heat exchanger in campaign 2, while methanotrophs and iron-reducing bacteria were abundant only in filter sediments. These findings could help to guide strategies for ecofriendly measures to reduce biofilm fouling in hydroelectric power plants, minimizing environmental and economic losses.

微生物污损（Microfouling）指物体表面形成生物膜的现象，该现象会对水力发电系统造成经济损失，并带来高昂的维护成本。本研究针对巴西伊拉佩水电站冷却系统（包含过滤器与热交换器）内的微生物群落开展调查，旨在筛选可用于更高效抑制生物膜形成的靶标细菌。
本次共开展两轮采样，对应巴西塞拉多（Cerrado）生物群系的两个典型季节：旱季采样（第一轮采样）与雨季采样（第二轮采样）。在热交换器末次清洁后的不同时段采集的样本中，微生物污损群落随时间推移呈现出显著差异。第二轮采样中，热交换器的微生物污损样本内仅存在且大量富集了嗜热细菌栖热菌属（Meiothermus）、热单胞菌属（Thermomonas）与共生杆菌属（Symbiobacterium）；而甲烷氧化菌（methanotrophs）与铁还原菌（iron-reducing bacteria）则仅在过滤器沉积物中大量富集。
本研究结果可为制定环保型污损防控策略以降低水电站生物膜污损提供参考，从而最大限度减少环境与经济损失。