Thermophilic (55C) dark fermentation is currently the main biotechnological approach</p><p>studied to recover value-added products (biohydrogen and organic acids) from sugarcane</p><p>vinasse within the context of two-stage anaerobic digestion. Although practical results show</p><p>that this process offers a great metabolic flexibility, the understanding on the microbes</p><p>involved in substrate conversion is still full of gaps. The microbial communities of four</p><p>thermophilic fixed-bed vinasse-fed fermentative reactors were analyzed by 16S rRNA gene</p><p>amplicon sequencing. A functional prediction was also made by aligning the marker gene data</p><p>with reference genomes deposited in databases.