Metaproteomics, heterotrophic growth, and distribution of nitrosomonas europaea and nitrobacter winogradskyi after long-term operation of an autotrophic nitrifying biofilm reactor

Research output: Contribution to journalArticlepeer-review


Institutes & Expert groups

  • UAB - Universitat Autonoma de Barcelona
  • CMET - Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University


Bioregenerative life support systems (BLSS) are currently in development to tackle low recovery efficiencies, high energy demands, as well as food, water, and oxygen production challenges through the regeneration of nutrients from waste streams. The MELiSSA pilot plant has been developed as a testbed for regenerative life support system bioreactor operation and characterization. As nitrogen is a vital resource in such systems, we studied the functional composition of a new packed-bed nitrifying bioreactor inoculated with a co-culture of Nitrosomonas europaea (ATCC 25978) and Nitrobacter winogradskyi (ATCC 25391). After 840 days of autotrophic continuous cultivation, the packed-bed was sampled at five vertical positions, each with three horizontal positions, and the biomass at each position was characterized via qPCR, 16S amplicon sequencing, and liquid chromatography tandem mass spectrometry. The total number of cells within the different sections fluctuated around 8.95±5.10×107 cells/mL of beads. Based on 16S amplicons and protein content, N. europaea and N. winogradskyi constituted overall 44.07±11.75% and 57.53±12.04% of the nitrifying bioreactor, respectively, indicating the presence of a heterotrophic population that, even after such a long operation time, did not affect the nitrification function of the bioreactor. In addition, DNA-based abundance estimates showed that N. europaea was slightly more abundant than N. winogradskyi, whereas protein-based abundance estimates indicated a much higher abundance of N. europaea. This highlights that single-method approaches need to be carefully interpreted in terms of overall cell abundance and metabolic activity.


Original languageEnglish
Article number201002
Pages (from-to)272-287
Number of pages16
JournalApplied Microbiology
Issue number1
Publication statusPublished - 9 Mar 2022


  • Nitrosomonas europaea, Nitrobacter winogradskyi, Nitrification, Bioreactor, Life support system, BLSS, RLSS

ID: 7520021