Elucidating functional microorganisms and metabolic mechanisms in a novel engineered ecosystem integrating C, N, P and S biotransformation by metagenomics

Abstract

Denitrifying sulfur conversion-associated enhanced biological phosphorous removal (DS-EBPR) system is not only a novel wastewater treatment process, but also an ideal model for microbial ecology in a community context. However, it exists the knowledge gap on the roles and interactions of functional microorganisms in the DS-EBPR system for carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) bioconversions. We use genome-resolved metagenomics to build up an ecological model of microbial communities in a lab-scale DS-EBPR system with stable operation for more than 400 days. Our results yield 11 near-complete draft genomes that represent a substantial portion of the microbial community (39.4%).Sulfate-reducing bacteria (SRB) and sulfide-oxidizing bacteria (SOB) promote complex metabolic processes and interactions for C, N, P and S conversions. Bins 1-4 and 10 are considered as new potential polyphosphate-accumulating organisms (PAOs), in which Bins 1-4 can be considered as S-related PAOs (S-PAOs) with no previously cultivated or reported members. Our findings give an insight into a new ecological system with C, N, P and S simultaneous bioconversions and improve the understanding of interactions among SRB, SOB, denitrifiers and PAOs within a community context.

Metagenomic insights into mixotrophic denitrification facilitated nitrogen removal in a full-scale A2/O wastewater treatment plant

“…denitrification process [3,8,15], SRB were not the dominant taxa in the A2/O process. However, the guild of SRB showed high diversity in our study (40 genera) (S3 Table ).…”

“…Ignavibacterium (7.3%-8.4%) was the most dominant genus in the AS community, which was associated with sulfur-based autotrophic denitrifying processes, converting NO 2 and NO to N 2 [36,37]. Thiobacillus (4.9%-5.6%) was the third most abundant taxon, which was previously reported to be the dominant taxon in sulfur-based autotrophic denitrification bioreactors and could also cooperate with heterotrophic denitrifiers in heterotrophic environments [8,11,15,32]. Sulfuritalea (0.80%-0.91%) and Thauera (0.65%-0.76%) were also found to act as sulfur-driven autotrophic denitrifiers [13].…”

“…As sustainable wastewater treatment becomes a priority, autotrophic denitrification processes based on sulfur oxidation have become increasingly popular [3][4][5]. Sulfur-based autotrophic denitrification, such as the sulfate reduction autotrophic denitrification nitrification integrated (SANI 1 ) process and sulfur-limestone autotrophic denitrification (SLAD), has been comprehensively studied [3,[5][6][7][8]. In these processes, chemolithotrophic sulfide-oxidizing denitrifying bacteria (SONB) (Thiobacillus sp., Sulfurimonas denitrificans, Beggiatoa sp., and Thiothrix sp.)…”

“…and heterotrophic sulfide-oxidizing denitrifiers (Thauera-like taxa, Azoarcus, Pseudomonas, and Dechloromonas) cooperate in the processes of N removal [3,5,[9][10][11][12][13][14]. Moreover, sulfate reducing bacteria (SRB), such as Desulfobacteraceae, Desulfonema, and Thermotogaceae, in activated sludge (AS), which convert sulfate to sulfur, sulfide, and poly-S, could cooperate with SONB and enhance N removal by providing electron donors [3,8,15].…”

Enhanced Simultaneous Nitrogen and Phosphorus Removal in A Denitrifying Biological Filter Using Waterworks Sludge Ceramsite Coupled with Iron-Carbon

“…Dechloromonas are glycogen accumulating organisms that have a strong NO 3 − -N reduction capacity [19]. Some studies have shown that glycogen accumulating organisms can produce N 2 O during denitrification, thereby promoting N removal [20,21]. Pseudomonas and Acinetobacter have been shown to perform both heterotrophic nitrification and aerobic denitrification [22].…”