Influence of Sucrose on the Diversity of Bacteria Involved in Nonionic Surfactant Degradation in Fluidized Bed Reactor

The microbial diversity from a fluidized bed reactor (FBR) for nonionic surfactant linear alcohol ethoxylate (LAE - Genapol (R) C100) degradation was determined by 454-pyrosequencing analysis. The FBR was operated with a hydraulic retention time of 18 h for 163 days and fed with synthetic substrate supplemented with yeast extract and LAE. The system was operated in two stages: (I) 80 mg/L of sucrose in synthetic substrate plus 107.4 +/- 47.3 mg/L LAE and (II) synthetic substrate without sucrose and 97.9 +/- 37.7 mg/L of LAE. By using 454 pyrosequencing, 14,325 sequences with an average length of 225 bp were generated. Proteobacteria phyla predominated in support material (sand) biofilm, while for the biomass from the phase separator, there was a prevalence of Acidobacteria phyla. Furthermore, many reads were related to genera of degraders of LAE and other nonionic surfactants (Desulfosporomusa, Syntrophomonas, Desulfobulbus, Geobacter, Dongia, etc.). Higher diversity and equitability indices were obtained for the biomass from the phase separator. The use of sucrose (C12H22O11) as co-substrate for LAE degradation favored the microbial diversity in the support material and in the phase separator, indicated by the Shannon-Wiener (H') index. The removal of sucrose from the synthetic substrate definitely altered the microbial community but did not influence the LAE efficiency removal.