Abstract: To reveal the genetic background and the mechanisms of petroleum hydrocarbon degradation inBrevundimonas diminutaDB-19, Illumina sequencing, Nanopore sequencing and bioinformatics methods were used to analyze the genome of strain DB-19. The complete genome sequences of strain DB-19 were obtained. One contig was obtained after genome assembly, and its type was circular chromosome. The genome size was 3589837 bp, and the GC content was 67.38%. A total of 3609 genes coding for proteins were predicted. Fifty-two tRNA genes were found using the tRNAscan-SE. The number of genes coding for 16S rRNA, 5S rRNA, 23S rRNA and sRNA was 2, 2, 2 and 1, respectively. Gene function annotation showed that the number of genes annotated in the NR, Swiss-Prot, COG, GO, Pfam, PHI, VFDB, ARDB, KEGG and CAZy databases was 3401, 2189, 2854, 1714, 2817, 812, 629, 1, 3193 and 89, respectively. According to the identified genes, it was inferred that terminal oxidative pathway was the main pathway for the degradation of n-alkanes in strain DB-19, and that homogentisate pathway and β-ketoadipate pathway played main roles in the degradation of aromatic compounds. These results deepened our understanding ofB. diminuta, contributed to designing more effective methods for the remediation of petroleum pollution, and provided important reference for studying the mechanisms of pollutant degradation in other microorganisms.

Key words: Brevundimonas diminuta, genome, petroleum, alkane, aromatic hydrocarbon