Sulfidogenesis vs homoacetogenesis

This study addresses all questions raised by assessing the impacts of the availability of bicarbonate and sulfate concentrations on both the establishment of sulfidogenesis and the subsequent losses in bioH2 production in the DF of sugarcane vinasse. A central composite rotational design (CCRD) using both the CODt/sulfate and NaHCO3/CODt ratios as the independent variables coupled to response surface methodology (RSM) were carried out in batch reactors under thermophilic (55 grade C) conditions, from which models describing the evolution of bioH2 and the sulfate reduction were obtained and validated. BioH2 evolution patterns were also assessed in complementary tests under varying pH levels and using sugarcane vinasses from different sources. 16S rRNA gene amplicon sequencing was finally used to identify the main microbial groups providing such a high metabolic versatility to the DF of sugarcane vinasse.