Population Changes of Eubacteria, Sulfate-Reducing Bacteria and Methanogenic Archaea in an Anaerobic Reactor Processing Ethanol Distillery Vinasse

Abstract

HIGHLIGHTS• UASB reactors are widely used in vinasse wastewater.• Archaea, Bacteria Domain and sulfate-reducing bacteria.• Population differences were found by DGGE technique.• PCRq was effective in the quantitative differentiation among populations. • Brown, A. I. T..; et al. Abstract:The microbiological characterization by molecular techniques (DGGE and quantitative PCR) of Archaea, Bacteria domain and sulfate-reducing bacteria (SRB) from a laboratory scale Up-flow Anaerobic Sludge Blanket (UASB) processing sugar cane vinasse was performed during the operational phase with increasing organic loads. The organic load removal efficiency was between 97% and 75% for volumetric organic loads (VOL) in the range of 0.6 to 15.4 kgCOD.m -3 .d −1 and for higher VOL (until 27.0 kgCOD.m -3 .d −1 ) the removal efficiency decreased to 48%. Archaea represented the majority of the estimated population (10 7 copies of 16S RNA ribosomal gene. mL -1 ) followed by bacteria (10 6 copies of 16S RNA ribosomal gene. mL -1 ) and sulfate-reducing bacteria (SRB) (10 5 copies of dsrB gene. mL -1 ). There was a significant difference between the populations of Archaea and SRB with increasing VOL. DGGE profiles show differences among populations with increasing VOL, especially with respect to sulfate-reducing bacteria. The presence of SRB together with a high sulfate removal percentage (97%) of about 15 kgCOD.m -3 d -1h , indicates the establishment of a sulfidogenic process.