Complete genome sequence of Halomonas boliviensis strain kknpp38, a chlorine-resistant bacterium isolated from the early-stage marine biofilm.

Abstract

H. boliviensis strain kknpp38 is a dense exopolysaccharide (EPS) producing bacterium, isolated from the early-stage (72-h-old) of marine biofilm. Laboratory experiments demonstrated that this isolate forms a potent biofilm on various artificial substrata viz. polystyrene, stainless steel as well as titanium and possesses high tolerance to chlorine disinfection. To determine the genes and biosynthetic pathways involved in the EPS production, whole-genome sequencing was performed using high-throughput Illumina tag sequencing. The high-quality reads were first de novo assembled using Unicycler genome assembler (version 0.4.9b) and then annotated using Prokka (version 1.13). The complete genome comes from one circular chromosome containing 4.96 Mbp DNA with G+C content of 55%, and encompasses genes encoding 4476 proteins, 2 rRNAs, and 57 tRNAs. Intriguingly, genomic analysis revealed the existence of genes involved in ATP-binding cassette (ABC) transporter-dependent EPS biosynthesis pathways (ugd, ugd2, galU). In addition, we identified genes involved in ectoine (ectA, ectB, ectC, ectD) and polyhydroxyalkanoates (PHAs; fabA, fabB, fabD, fabF, fabH, fabV, fabZ, phaC, phaD, phaG, phaR, phaZ1) production, which are known to involve in bacterial adaptation in saline environment. The outcomes of this study expand scientific understanding on the genes and pathways involved in EPS biosynthesis by marine bacteria.