## 3 Results and Discussion
### Microbial Community Composition  
At the end of the electrochemical experiments, different bioanodes named STWW/TB/SSM, STWW/BR/SCD, STWW/TB/SCD, STWW/BR/SSM, RTWW/SCD, and RTWW/SSM were removed from the reactors and subjected to a metagenomic study to probe the variation of bacterial communities within biofilms as a function of the nature of the inoculums (SSM or SCD) and the wastewater (STWW or RTWW). The composition and abundance distribution of each biofilm at the taxonomic levels of phylum and species are shown in Figure 8A,B. At the phylum level, biofilms were mainly colonized by two phyla: _Proteobacteria_ (from 87 to 31%) and _Firmicutes_ (from 60 to 31%). _Proteobacteria_ were enriched in the pattern of abundance 87% (RTWW/SSM) > 68% (STWW/TB/SCD) > 62% (STWW/TB/SSM) > 54% (STWW/BR/SCD) > 33% (RTWW/SCD) > 31% (STWW/BR/SSM). However, _Firmicutes_ were enriched in a different pattern of abundance: 60% (RTWW/SCD) > 50% (RTWW/SSM) > 43% (STWW/BR/SSM) = 43% (STWW/BR/SCD) > 36% (STWW/TB/SSM) > 31% (STWW/TB/SCD). Additionally, the phylum of _Eucyarchaeota_ was also enriched in Biofilms STWW/BR/SSM and STWW/BR/SCD collected from reactors, which contained STWW/BR with relative abundances of 24 and 22%, respectively. Figure 7: SEM micrographs of carbon felt anode under different magnifications used in BES for textile wastewater treatment and power generation:(**A**) STWW1 (TB); (**B**) STWW2 (BR); (**C**) RTWW. At the species level, biofilms formed in synthetic wastewater contained BR with SSM as inoculum source (STWW/BR/SSM), the most abundant bacteria were _Marinobacter hydrocarboncalcicus_ (27%), _Halanarobachum tunisiese_ (24%), _Halonera mucosum_ (20%), _Halanerobacter lacunarum_ (13%), _Halanarobibumlacurosei_ (6%), _Acetohalobium abaticum_ (4%), and _Orenia marismoruti_ (1.5%). However, biofilms formed in reactors contained synthetic wastewater containing TB treated with the same sediment (STWW/TB/SSM) were mainly colonized by _Caenispirillum_ sp. (15%), _Halanarobacter lacunarum_ (13.6%), _Desulfoibrio_ sp. (10%), _Chromolobacter thailandensis_ (15.5%), _Achromobacter xylos oxidans_ (11 %), _Azospirillum_ sp. (10%), _Achromolobacter xylos oxidans_ (11 %), _Astronomy_ (10%), _Astronomy_ (10%), _Astronomy_ (  
oryzae_ (6%), _Halanarobium lacurosei_ (7%), _Novispirillum_ spp. (5%), _Desulfotomaculum_ sp. (3%), _Crenia salina_ (3%), and _Halanarobachum tunisiense_ (2%). Biofilms formed in synthetic wastewater contained TB inoculated with SCD as a source of biocatalyst microorganisms (STWW/TB/SCD) were colonized mainly by the species of _Marinobacter_ sp. (71%), _Clostridium_ sp. (13.6%), _Caldinitratriuptor Clostridales bacterium_ (5%), and _Desulfotolaculum_ sp. (4%).While in the case of the synthetic wastewater contained BR treated with the same sediment (STWW/BR/SCD), the biofilms were mainly colonized by _Marinobacter hydrocarboclasticus_ (50%), _Crenia salina_ (14%), _Sporolabolacter_ sp. (12%), _Acetolabolium arabaticum_ (6%), _Halothiobacillus hydrothermalis_ (5%),and _Halanarobachum tunisiense_ (4%). These findings clearly revealed an important diversity in the microbial community that colonized the different biofilms. It is important to note that wastewater treated with SCD demonstrated the highest degradation potential and electric current densities; this could be attributed to the microbial community that hosts this sediment mainly being colonized by the genus of _Marinobacter_. This genus has been described as extremely halotolerant with great potential in bioremediation [46]. _Marinobacter hydrocarbonoclasticus_ has previously been shown to degrade a wide range of n-alkanes [47]and hydrocarbons [46; 48]. Recent genetic studies have shown that its broad metabolic capacity indicates that it should rather be considered as a multipurpose bacterium [49]. Furthermore, the electrogenicity of this strain is increasingly proven. It was described as a major species in a halotermotolerant biofilm designed by [PERSON] et al. [21]. In the same sense [PERSON] et al.