Physiological and Genomic Analysis of Bacillus pumilus UAMX Isolated from the Gastrointestinal Tract of Overweight Individuals

Abstract

The study aimed to evaluate the metabolism and resistance to the gastrointestinal tract conditions of Bacillus pumilus UAMX (BP-UAMX) isolated from overweight individuals using genomic tools. Specifically, we assessed its ability to metabolize various carbon sources, its resistance to low pH exposure, and its growth in the presence of bile salts. The genomic and bioinformatic analyses included the prediction of gene and protein metabolic functions, a pan-genome and phylogenomic analysis. BP-UAMX survived at pH 3, while bile salts (0.2–0.3% w/v) increased its growth rate. Moreover, it showed the ability to metabolize simple and complex carbon sources (glucose, starch, carboxymethyl-cellulose, inulin, and tributyrin), showing a differentiated electrophoretic profile. Genome was assembled into a single contig, with a high percentage of genes and proteins associated with the metabolism of amino acids, carbohydrates, and lipids. Antibiotic resistance genes were detected, but only one beta-Lactam resistance protein related to the inhibition of peptidoglycan biosynthesis was identified. The pan-genome of BP-UAMX is still open with phylogenetic similarities with other Bacillus of human origin. Therefore, BP-UAMX seems to be adapted to the intestinal environment, with physiological and genomic analyses demonstrating the ability to metabolize complex carbon sources, the strain has an open pan-genome with continuous evolution and adaptation.

Comparative Genome Analysis of Two Bacillus pumilus Strains Producing High Level of Extracellular Hydrolases

“…The NCBI database already includes 17 complete circular genomes and 156 genomes in scaffold/contigs level of B. pumilus strains (September 2021). The known strains of B. pumilus show high resistance to environmental parameters [ 2 , 4 , 8 ]. The B. pumilus SAFR-032 strain exhibits high survival rates under exposure to outer space conditions in experiments onboard the International Space Station (ISS) [ 4 ].…”

“…Strain PDSLzg-1 isolated from oil-contaminated soil shows the ability to degrade hydrocarbons [ 9 ]. Isolated from the human gastrointestinal tract, the UAMX strain is able to metabolize various carbon sources, shows resistance to low pH values (pH = 3.0), and the presence of bile salts stimulates its growth [ 8 ].…”