N ₂ ‐fixation can sustain wastewater treatment performance of photogranules under nitrogen limiting conditions

TY - JOUR

T1 - N 2 ‐fixation can sustain wastewater treatment performance of photogranules under nitrogen limiting conditions

AU - Trebuch, Lukas M.

AU - Schoofs, Kobe

AU - Vaessen, Stijn M. F.

AU - Neu, Thomas R.

AU - Janssen, Marcel

AU - Wijffels, René H.

AU - Vet, Louise E. M.

AU - Fernandes, Tânia V.

N1 - Data archiving: on request

PY - 2023/2/25

Y1 - 2023/2/25

N2 - Wastewater characteristics can vary significantly, and in some municipal wastewaters the N:P ratio is as low as 5 resulting in nitrogen-limiting conditions. In this study, the microbial community, function, and morphology of photogranules under nitrogen-replete (N+) and limiting (N−) conditions was assessed in sequencing batch reactors. Photogranules under N− condition were nitrogen deprived 2/3 of a batch cycle duration. Surprisingly, this nitrogen limitation had no adverse effect on biomass productivity. Moreover, phosphorus and chemical oxygen demand removal were similar to their removal under N+ conditions. Although performance was similar, the difference in granule morphology was obvious. While N+ photogranules were dense and structurally confined, N− photogranules showed loose structures with occasional voids. Microbial community analysis revealed high abundance of cyanobacteria capable of N2-fixation. These were higher at N− (38%) than N+ (29%) treatments, showing that photogranules could adjust and maintain treatment performance and high biomass productivity by means of N2-fixation.

AB - Wastewater characteristics can vary significantly, and in some municipal wastewaters the N:P ratio is as low as 5 resulting in nitrogen-limiting conditions. In this study, the microbial community, function, and morphology of photogranules under nitrogen-replete (N+) and limiting (N−) conditions was assessed in sequencing batch reactors. Photogranules under N− condition were nitrogen deprived 2/3 of a batch cycle duration. Surprisingly, this nitrogen limitation had no adverse effect on biomass productivity. Moreover, phosphorus and chemical oxygen demand removal were similar to their removal under N+ conditions. Although performance was similar, the difference in granule morphology was obvious. While N+ photogranules were dense and structurally confined, N− photogranules showed loose structures with occasional voids. Microbial community analysis revealed high abundance of cyanobacteria capable of N2-fixation. These were higher at N− (38%) than N+ (29%) treatments, showing that photogranules could adjust and maintain treatment performance and high biomass productivity by means of N2-fixation.

U2 - 10.1002/bit.28349

DO - 10.1002/bit.28349

M3 - Article

SN - 0006-3592

JO - Biotechnology and Bioengineering

JF - Biotechnology and Bioengineering

ER -