Genome analysis of a thermophilic exopolysaccharide-producing bacterium - Geobacillus sp. WSUCF1

Jia Wang,Kian Mau Goh,Rajesh K Sani,David R Salem

doi:10.1038/s41598-018-36983-z

Jia Wang, Kian Mau Goh + Show 2 more

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https://doi.org/10.1038/s41598-018-36983-z

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Abstract

Geobacillus sp. WSUCF1 is a Gram-positive, spore-forming, aerobic and thermophilic bacterium, isolated from a soil sample obtained from a compost facility. Strain WSUCF1 demonstrated EPS producing capability using different sugars as the carbon source. The whole-genome analysis of WSUCF1 was performed to disclose the essential genes correlated with nucleotide sugar precursor biosynthesis, assembly of monosaccharide units, export of the polysaccharide chain, and regulation of EPS production. Both the biosynthesis pathway and export mechanism of EPS were proposed based on functional annotation. Additionally, the genome description of strain WSUCF1 suggests sophisticated systems for its adaptation under thermophilic conditions. The presence of genes associated with CRISPR-Cas system, quorum quenching lactonase, polyketide synthesis and arsenic resistance makes this strain a potential candidate for various applications in biotechnology and biomedicine. The present study indicates that strain WSUCF1 has promise as a thermophilic EPS producer for a broad range of industrial applications. To the best of our knowledge, this is the first report on genome analysis of a thermophilic Geobacillus species focusing on its EPS biosynthesis and transportation, which will likely pave the way for both enhanced yield and tailor-made EPS production by thermophilic bacteria.

Highlights

Geobacillus genus bacteria are Gram-positive, rod-shaped, aerobic or facultatively anaerobic, spore-forming thermophiles with an optimum growth temperature range of 55 to 65 °C1–3
The genome annotation of the draft genome of strain WSUCF1 using PATRIC genome annotation service demonstrated 4184 coding sequences and of these genes, 82 were RNA genes (Table 1). 2342 protein-coding genes were assigned to 129 pathways, which was 55.98% of the total coding sequences
The Geobacillus sp. strain WSUCF1 is a cellulose-degrading bacterium (CDB) which produces a complete repertoire of highly thermostable lignocellulolytic enzymes[41]

Summary

Introduction

Geobacillus genus bacteria are Gram-positive, rod-shaped, aerobic or facultatively anaerobic, spore-forming thermophiles with an optimum growth temperature range of 55 to 65 °C1–3. The Geobacillus spp. strains are irreplaceable microbial contributors to the biotechnological industry due to their valuable thermostable lignocellulolytic enzymes and other thermoactive bioproducts[5]. It is well-acknowledged that the macromolecules produced from thermophiles - such as thermozymes, thermostable proteins, and exopolysaccharides (EPSs) - improve the ability of the cells to withstand harsh environmental factors[6,7]. The motivation for sequencing of Geobacillus species strains was to investigate the genes involved in bioremediation, biofuel production, and enzymatic degradation of long-chain molecules and polymeric substrates[18,19,20,21]. The role of regulatory systems remains only partially understood in terms of how the signal molecules may impact thermophilic EPS biosynthesis

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