Neobacillus driksii
sp. nov. isolated from a Mars 2020 spacecraft assembly facility and genomic potential for lasso peptide production in
Neobacillus
Authors: Hameed Asif , McDonagh Francesca , Sengupta Pratyay , Miliotis Georgios , Sivabalan Shobhan Karthick Muthamilselvi , Szydlowski Lukasz , Simpson Anna , Singh Nitin Kumar , Rekha Punchappady Devasya , Raman Karthik , Venkateswaran Kasthuri 
Published: November 2024

ABSTRACT

During microbial surveillance of the Mars 2020 spacecraft assembly facility, two novel bacterial strains, potentially capable of producing lasso peptides, were identified. Characterization using a polyphasic taxonomic approach, whole-genome sequencing and phylogenomic analyses revealed a close genetic relationship among two strains from Mars 2020 cleanroom floors (179-C4-2-HS, 179-J1A1-HS), one strain from the Agave plant (AT2.8), and another strain from wheat-associated soil (V4I25). All four strains exhibited high 16S rRNA gene sequence similarity (>99.2%) and low average nucleotide identity (ANI) with
Neobacillus niacini
NBRC 15566
T
, delineating new phylogenetic branches within the genus. Detailed molecular analyses, including
gyr
B (90.2%), ANI (86.4%), average amino acid identity (87.8%) phylogenies, digital DNA–DNA hybridization (32.6%), and percentage of conserved proteins (77.7%) indicated significant divergence from
N. niacini
NBRC 15566
T
. Consequently, these strains have been designated
Neobacillus driksii
sp. nov., with the type strain 179-C4-2-HS
T
(DSM 115941
T
= NRRL B-65665
T
).
N. driksii
grew at 4°C to 45°C, pH range of 6.0 to 9.5, and 0.5% to 5% NaCl. The major cellular fatty acids are iso-C
15:0
and anteiso-C
15:0
. The dominant polar lipids include diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. Metagenomic analysis within NASA cleanrooms revealed that
N. driksii
is scarce (17 out of 236 samples). Genes encoding the biosynthesis pathway for lasso peptides were identified in all
N. driksii
strains and are not commonly found in other
Neobacillus
species, except in 7 out of 26 recognized species. This study highlights the unique metabolic capabilities of
N. driksii
, underscoring their potential in antimicrobial research and biotechnology.

IMPORTANCE

The microbial surveillance of the Mars 2020 assembly cleanroom led to the isolation of novel
N. driksii
with potential applications in cleanroom environments, such as hospitals, pharmaceuticals, semiconductors, and aeronautical industries.
N. driksii
genomes were found to possess genes responsible for producing lasso peptides, which are crucial for antimicrobial defense, communication, and enzyme inhibition. Isolation of
N. driksii
from cleanrooms, Agave plants, and dryland wheat soils, suggested niche-specific ecology and resilience under various environmentally challenging conditions. The discovery of potent antimicrobial agents from novel
N. driksii
underscores the importance of genome mining and the isolation of rare microorganisms. Bioactive gene clusters potentially producing nicotianamine-like siderophores were found in
N. driksii
genomes. These siderophores can be used for bioremediation to remove heavy metals from contaminated environments, promote plant growth by aiding iron uptake in agriculture, and treat iron overload conditions in medical applications.