Denaturing Gradient Gel Electrophoresis Analysis of Archaeal and Bacterial Populations in a Submerged Anaerobic Membrane Bioreactor Treating Landfill Leachate at Low Temperatures

摘要

This study investigated the evolution of archaeal and bacterial populations of two submerged anaerobic membrane bioreactors (SAMBRs) operating at a mean solids residence time of 30 (SAMBR30) and 300 days (SAMBR300) at mesophilic and psychrophilic temperatures. SAMBRs were fed with leachate produced in a hydrolytic reactor (HR) treating the organic fraction of municipal solid waste. The archaeal fingerprint using denaturing gradient gel electrophoresis showed different populations in the first and second stage of the two-stage anaerobic process. A build up of volatile fatty acids (VFAs) was observed at 20°C in SAMBR30; whereas in SAMBR300, the VFAs only built up at 10°C. The dominant bacterial species in the HR belonged to Prevotella and Thauera, whereas the dominant ones in SAMBR300 belonged to Sphingobacteriales, Anaerovorax, Spirochaetaceae, Hydrogenophaga, Ralstonia, Prevotella, and Smithella. Low bacterial diversity in SAMBR30 compared with SAMBR300 resulted in a persistently high soluble chemical oxygen demand (>2 g/L) in the bulk reactor due to an insufficient residence time for bacteria to carry out the degradation of recalcitrant chemical oxygen demand found in the leachate.