Microbial community dynamics in anaerobic bioreactors and algal tanks treating piggery wastewater

Integrated biosystem is becoming a major aspect of wastewater management practice. Microbial communities in piggery wastewater sampled from anaerobic (thermophilic and mesophilic) and aerobic digesters (algal tanks) during waste remediation were analyzed by culture-independent techniques based on polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The use of Muyzer's 314F-GC, 518R bacterial primers, and archaeal A934F, 1309R primers followed by partial 16s rDNA sequence analysis of the main bands from DGGE revealed the presence of unknown and as yet uncultured microorganisms but also showed functional and ecologically significant denitrifying, acetogenic bacteria along with autotrophic, hydrogenotrophic, and acetoclastic methanogen archaea. Thermophilic digesters were dominated by ?-Proteobacteria, Methanothermobacter sp., while mesophilic digesters showed dominance by Firmicutes, uncultured bacteria, Methanosarcina, and Methanoculleus genera. Under aerobic conditions within algal tanks, pH rose from 7.17 to 9.32, with a significant decrease in total ammonia nitrogen, chemical oxygen demand, and soluble phosphorus level