Degradation properties of fulvic acid and its microbially driven mechanism from a partial nitritation bioreactor through multi-spectral and bioinformatic analysis
Jiachun Yang , Quanhao Dou , Li Zhang , Tingjun Dong , Zixuan Song , Xuepeng Fan , Yongzhen Peng , Xiayan Wang
DOI:10.1016/j.jes.2022.11.010
Received September 27, 2022,Revised , Accepted November 15, 2022, Available online November 23, 2022
Volume 36,2024,Pages 318-331
This study employed multispectral techniques to evaluate fulvic acid (FA) compositional characteristic and elucidate its biodegradation mechanisms during partial nitritation (PN) process. Results showed that FA removal efficiency (FRE) decreased from 90.22 to 23.11% when FA concentrations in the reactor were increased from 0 to 162.30 mg/L, and that molecular size, degree of aromatization and humification of the effluent FA macromolecules all increased after treatment. Microbial population analysis indicated that the proliferation of the Comamonas, OLB12 and Thauera exhibit high FA utilization capacity in lower concentrations (<50.59 mg/L), promoting the degradation and removal of macromolecular FA. In addition, the sustained increase in external FA may decrease the abundance of above functional microorganisms, resulting in a rapid drop in FRE. Furthermore, from the genetic perspective, the elevated FA levels restricted carbohydrate (ko00620, ko00010 and ko00020) and nitrogen (HAO, AMO, NIR and NOR) metabolism-related pathways, thereby impeding FA removal and total nitrogen loss associated with N2O emissions.
