Whole transcriptome analysis highlights nutrient limitation of nitrogen cycle bacteria in simulated microgravity

Tom Verbeelen; Celia Alvarez Fernandez; Thanh Huy Nguyen; Surya Gupta; Raf Aarts; Kevin Tabury; Baptiste Leroy; Ruddy Wattiez; Siegfried E Vlaeminck; Natalie Leys; Ramon Ganigué; Felice Mastroleo

doi:10.1038/s41526-024-00345-z

Whole transcriptome analysis highlights nutrient limitation of nitrogen cycle bacteria in simulated microgravity

NPJ Microgravity. 2024 Jan 10;10(1):3. doi: 10.1038/s41526-024-00345-z.

Authors

Affiliations

¹ Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium.
² Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
³ Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium.
⁴ Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium.
⁵ Centre for Advanced Process Technology for Urban REsource Recovery (CAPTURE), Frieda Saeysstraat 1, 9052, Ghent, Belgium.
⁶ Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium. Felice.mastroleo@sckcen.be.

Abstract

Regenerative life support systems (RLSS) will play a vital role in achieving self-sufficiency during long-distance space travel. Urine conversion into a liquid nitrate-based fertilizer is a key process in most RLSS. This study describes the effects of simulated microgravity (SMG) on Comamonas testosteroni, Nitrosomonas europaea, Nitrobacter winogradskyi and a tripartite culture of the three, in the context of nitrogen recovery for the Micro-Ecological Life Support System Alternative (MELiSSA). Rotary cell culture systems (RCCS) and random positioning machines (RPM) were used as SMG analogues. The transcriptional responses of the cultures were elucidated. For CO₂-producing C. testosteroni and the tripartite culture, a PermaLife^TM PL-70 cell culture bag mounted on an in-house 3D-printed holder was applied to eliminate air bubble formation during SMG cultivation. Gene expression changes indicated that the fluid dynamics in SMG caused nutrient and O₂ limitation. Genes involved in urea hydrolysis and nitrification were minimally affected, while denitrification-related gene expression was increased. The findings highlight potential challenges for nitrogen recovery in space.

Abstract

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