Complete genome sequence of Bacillus coagulans CACC834 isolated from canine

Bacillus coagulans strains are gram-positive, spore-forming, and produce lactic acid, which possesses the capacity to balance intestinal gut microbiota, ultimately promoting the growth of animals and improving immunity [1,2]. In addition, B. coagulans is resistant to high temperatures because of its probiotic activity, modulates and strengthens the immune system to protect against infections, and minimizes inflammation-related tissue damage [3].

We isolated B. coagulans CACC 834 (KACC 22145) from the feces of a female 3-year-old Boston terrier in Korea. The samples were incubated under anaerobic conditions at 37°C [4].

Whole-genome sequencing was performed using the Pacific Biosciences (PacBio) RS II Single Molecule Real Time (SMRT) platform with a 20 kb SMRTbell^TM template library at ChunLab. The reads were assembled using the PacBio SMAR Analysis 2.3.0. [5].

The sequences were annotated using the combined results of the automatic National Center for Biotechnology Information (NCBI) Prokaryotic Genome Annotation Pipeline (PGAP) and Rapid Annotations using Subsystems Technology (RAST) [6].

The complete genome of B. coagulans CACC 834 was composed of a 3,077,319 bp circular chromosome with 47.1% guanine (G) + cytosine (C) content. The genome contained 3,181 protein-coding sequences (CDS), 30 rRNAs, and 83 tRNAs (Table 1). The genome features of B. coagulans CACC 834 are summarized in Fig. 1. Among these CDS, 2,909 genes were classified into 20 clusters of orthologous groups (COG) functional categories (Fig. 1B). More than 41% of genes were involved in transport and metabolism, including amino acid, carbohydrate, inorganic ion, nucleotide, coenzyme, and lipid. Interestingly, 11% of the genes were involved in replication, recombination, and repair (Fig. 1B).

Fig. 1. Genome features of Bacillus coagulans CACC834. (A) Circular genome maps of B. coagulans CACC834 chromosome. Circles from the outside to the center denote rRNA and tRNA gene, reverse strand CDS, forward strand CDS, GC skew, and GC content. (B) Genome number of COG categorie. CDS, protein-coding genes; COG, clusters of orthologous group; G, guanine; C, cytosine.

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The genome of B. coagulans CACC 834 possessed hsp20, hsp60, dnaK, dnaJ and grpE operons, encoding enzymes and proteins for heat shock. Also, B. coagulans CACC 834 has heat shock induced genes, such as clpB, clpP, mcsB, and repair-related genes, such as recA and uvrABC. The expression of these genes is expected to help promote cell recovery from heat shock by limiting damage caused by stress [7–9]. Furthermore, B. coagulans CACC 834 carried genes known to be involved in lactate synthesis, adhesion, acid resistance, and bile resistance (Table 2).

This study on complete genome sequence of B. coagulans CACC 834 may increase our understanding of the probiotic effects in host healthcare and extend its potential application as an industrial strain.

The complete genome of B. coagulans strain CACC 834 determined in this study has been deposited in the NCBI GenBank database under accession number CP076597.