Ponente
Descripción
Anaerobic digestion (AD) involves the symbiotic interactions of distinct functional microorganisms, namely, hydrolytic and fermentative bacteria, acetogenic and syntrophic bacteria, and methanogenic archaea. This process converts organic matter into biogas, which is commonly used as an environmentally friendly and cost-efficient method for treating organic waste. This study evaluates the microbial profiling in sewage sludge (SW) during anaerobic digestion (AD) in a Biochemical Methane Potential (BMP) assay operating at 37±1°C monodigestion. The microbial community diversity and structure were characterized using Illumina MiSeq using the 16S rRNA. The taxonomic composition of total bacteria and archaeal communities in BMP AD reactors was investigated. The most represented phyla regarding the number of OTUs in SW before AD treatment were: Proteobacteria > Bacteroidetes > Actinobacteria > Firmicutes > Chloroflexi. After AD BMP assays, the bacterial community changed regarding relative abundance. A new dominant community configuration emerged in the system, as follows: Firmicutes > Synergistota > Proteobacteria > Actinobacteriota, which has been reported in several previous studies, suggesting the existence of a general signature of the AD microbiome. At the Genus level, the dominance of methanogenic groups was represented by Methanosaeta > Methanolinea > Methanofastidiosum > Methanospirillum > Methanosarcina before AD treatment and Methanobacterium > Methanosaeta after AD treatment. The observed changes in methanogenic profiles indicate a shift in the metabolic pathway for methane production from acetoclastic to hydrogenotrophic metabolism. The results and conclusions of this study are expected to increase the knowledge of the ecology and function of the involved microbial consortia, and thus, allow better control and optimization of AD at wastewater treatment plants (WWTPs). This metabolic transition may be linked to the increased abundance of Firmicutes, particularly Clostridia, which harbour acetate-oxidizing bacteria facilitating the conversion of acetate to hydrogen.
