Quantification of microbial communities in activated sludge containing lignin and chlorophenol from the pulp and paper industry as determined by 16S rRNA analysis

Activated sludge (AS) uses microbial communities to transform organic pollutants and nutrients to produce detoxified water, and in more advanced configurations, to recover resources. In this study, we investigated the bacterial populations and physico-chemical properties of AS from pulp paper industry. The physico-chemical analysis of AS showed that pH, color, total dissolved solids, total nitrogen, sulfate, sulfide, phosphate, electrical conductivity, Cl−, Na+, K+, lignin, chlorophenol, and heavy metals were all above permissible limits. The major microbial community detected in AS sample were Bacteroidetes (8 %), Proteobacteria (5 %), Spirochaetes (6 %), Chloroflexi (6 %), Betaproteobacteria (14 %), Anaerolineae (4 %), Burkholderiales (3 %), Rhodocyclacles (4 %), Spirochaetaceae (4 %), Desulfobacterace (3 %), and uncultured_gamma Proteobacteria (9 %). Moreover, other small species like uncultured_archaeon, uncultured Proteobacterium (1 %), Uncultured_Prokaryote (1 %), Tenericutes (1 %), and uncultured Anaeroliena (1 %) in AS. The findings revealed that species' relative abundance diversity and richness in microbial populations associated with AS differed significantly.