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Bacterial utilisation of aliphatic organics: is the dwarf planet Ceres habitable?

Citation

Jayasinghe, SA and Kennedy, F and McMinn, A and Martin, A, Bacterial utilisation of aliphatic organics: is the dwarf planet Ceres habitable?, Life, 12, (6) Article 821. ISSN 2075-1729 (2022) [Refereed Article]


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DOI: doi:10.3390/life12060821

Abstract

The regolith environment and associated organic material on Ceres is analogous to environments that existed on Earth 3–4 billion years ago. This has implications not only for abiogenesis and the theory of transpermia, but it provides context for developing a framework to contrast the limits of Earth’s biosphere with extraterrestrial environments of interest. In this study, substrate utilisation by the ice-associated bacterium Colwellia hornerae was examined with respect to three aliphatic organic hydrocarbons that may be present on Ceres: dodecane, isobutyronitrile, and dioctyl-sulphide. Following inoculation into a phyllosilicate regolith spiked with a hydrocarbon (1% or 20% organic concentration wt%), cell density, electron transport activity, oxygen consumption, and the production of ATP, NADPH, and protein in C. hornerae was monitored for a period of 32 days. Microbial growth kinetics were correlated with changes in bioavailable carbon, nitrogen, and sulphur. We provide compelling evidence that C. hornerae can survive and grow by utilising isobutyronitrile and, in particular, dodecane. Cellular growth, electron transport activity, and oxygen consumption increased significantly in dodecane at 20 wt% compared to only minor growth at 1 wt%. Importantly, the reduction in total carbon, nitrogen, and sulphur observed at 20 wt% is attributed to biotic, rather than abiotic, processes. This study illustrates that short-term bacterial incubation studies using exotic substrates provide a useful indicator of habitability. We suggest that replicating the regolith environment of Ceres warrants further study and that this dwarf planet could be a valid target for future exploratory missions.

Item Details

Item Type:Refereed Article
Keywords:Ceres, bacteria, astrobiology, Colwellia hornerae, aliphatic hydrocarbons
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Microbiology not elsewhere classified
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Jayasinghe, SA (Mr Sahan Jayasinghe)
UTAS Author:Kennedy, F (Dr Fraser Kennedy)
UTAS Author:McMinn, A (Professor Andrew McMinn)
ID Code:150181
Year Published:2022
Funding Support:Australian Research Council (SR200100008)
Deposited By:Ecology and Biodiversity
Deposited On:2022-06-01
Last Modified:2022-06-01
Downloads:0

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