Phosphorus Removal and Storage Polymer Synthesis by Tetrasphaera-Related Bacteria with Different Carbon Sources

Abstract

Tetrasphaera are polyphosphate-accumulating organisms (PAOs) prevalent in wastewater phosphorus removal systems. However, their metabolic versatility on carbon sources and correlations between carbon and phosphorus metabolism have not been fully elucidated. In this study, we identified a new clade of Tetrasphaera as the dominant PAO in a lab-scale phosphorus removal reactor. Both phosphorus release and uptake by Tetrasphaera-PAOs were more efficient with acetate than with glycerol and glucose. Fermentation of glycerol and glucose provided 4 and 1.7 times more energy than poly-P hydrolysis, and the trade-off between the two processes resulted in poor phosphorus release. Raman-fluorescence in situ hybridization suggested that polyhydroxyalkanoates (PHA) were synthesized from acetate. Glycogen, on the other hand, was the key energy storage compound formed using glycerol and glucose. Aerobic phosphorus uptake with acetate was 4.4 and 1.8 times more efficient than glycerol and glucose due to the additional energy supplied by PHA hydrolysis. The metabolic versatility and fermentation capability of Tetrasphaera-PAOs supported their prevalence in EBPR and underlined their potential metabolic interactions with other populations in the community. This work adds to our understanding of the genetic and metabolic divergence of Tetrasphaera-PAOs, providing useful information for the optimization of wastewater phosphorus removal under varied carbon source conditions.

Meta-omic profiling reveals ubiquity of genes encoding for the nitrogen-rich biopolymer cyanophycin in activated sludge microbiomes

“…Furthermore, the Group 2 gene cluster harbored genes for glycogen synthesis and storage including glycogen synthetase glgA and glucose-1-adenylyltransferase glgC, as well as the amino acid utilization gene phosphoserine phosphatase serB . Glycogen is an important carbon reserve for Tetrasphaera, as they utilize glycogen under anaerobic conditions and replenish stores during aerobic conditions ( Close et al, 2021 ; Yu et al, 2023 ).…”

Meta-omic profiling reveals ubiquity of genes encoding for the high value nitrogen rich biopolymer cyanophycin in activated sludge microbiomes

“…Furthermore, the Tetrasphaera cphA gene cluster also consisted of key genes for glycogen synthesis and storage including glycogen synthetase glgA and glucose-1-adenylyltransferase glgC, as well as the amino acid utilization gene phosphoserine phosphatase serB. Glycogen is an important carbon reserve for Tetrasphaera; they typically consume glycogen under anaerobic conditions and replenish stores during aerobic conditions (Close et al, 2021;Yu et al, 2023). The clustering of cphA and cphB with these key glycogen synthesis genes suggests that cyanophycin may be another important carbon and N storage compound for Tetrasphaera.…”