Active assimilators of soluble microbial products in wastewater anammox processes
Rui Xiao1, Shaoyi Xu1, Huijie Lu1*
1Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, 310058, Hangzhou, China
* e-mail correspondence: luhuijie@zju.edu.cn
Context.
The soluble microbial products (SMP) secreted by anammox bacteria (AnAOB) supported the growth of diverse heterotrophs in the community, which actively interact with AnAOB and interfere with the carbon and nitrogen cycles. These heterotrophic bacteria mainly included fermentors, denitrifying bacteria, dissimilatory nitrate reduction to ammonium (DNRA) bacteria, accounting for up to 70% of the wastewater anammox communities.
Gap.
There is a lack of information on what microbes actively assimilate SMP secreted by AnAOB, as well as how they interact with each other and with AnAOB.
Aim.
This study aimed to unravel the active assimilators of AnAOB microbial products and their metabolic interactions in wastewater anammox processes treating medium strength wastewater.
Findings.
Fermenters Anaerolineaceae, denitrifiers Gemmatimonadaceae and Burkholderiaceae were the active utilizers of the endogenous organics produced by the predominant AnAOB Candidatus Kuenenia. Approximately 40% of the assimilated 13CO2 was secreted as UAP by AnAOB, and the yield of fermenters and denitrifiers on UAP were 0.34. These populations potentially utilized amino acids (e.g. glycine, phenylalanine), fatty acids (e.g. galactonic acid) and biotin (e.g. vitamin B12). Metabolic network between AnAOB and active heterotrophs revealed that molybdopterin cofactor (MOCO) and folate essential for anammox acetyl-CoA synthesis were likely supplied by Gemmatimonadaceae and Burkholderiaceae, and fermentative Anaerolineceae potentially provided methionine to AnAOB for ladderane synthesis.
Utilization.
The improved knowledge onsoluble microbial products utilizers would help the optimization of anammox communities in both sidestream and mainstream towards enhanced total nitrogen removal and process stability.
Acknowledgement. This work was funded by the Key Research and Development project in Zhejiang Province, the Fundamental Research Funds for the Central Universities.
