Polyphasic Characterization and Genomic Insights into an Aerobic Denitrifying Bacterium, Shewanella zhuhaiensis sp. nov., Isolated from a Tidal Flat Sediment.

A new, facultatively anaerobic, light-yellow, and rod-shaped bacterium designated as 3B26 T isolated from Qi'ao Island's tidal flat sediment was identified. Strain 3B26 T can hydrolyze gelatin, aesculin, and skim milk. The major cellular fatty acids were identified as iso-C 15:0 , referred to as summed feature 3, and C 16:0 ; the polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, and phospholipid; and the quinones contained Q-7, Q-8, MK-7, and MMK7. The genomic size of strain 3B26 T was 4,682,650 bp, and its genomic DNA G + C content was 54.8%. While a 16S rRNA gene-based phylogenetic analysis confirmed that strain 3B26 T belongs to the genus Shewanella , both phylogenomic inference and genomic comparison revealed that strain 3B26 T is distinguishable from its relatives, and digital DNA-DNA hybridization (dDDH) values of 24.4-62.6% and average nucleotide identities (ANIs) of 83.5-95.6% between them were below the 70% dDDH and 96% ANI thresholds for bacterial species delineation. Genomic functional analysis demonstrated that strain 3B26 T possesses complete gene clusters of eicosapentaenoic acid biosynthesis and denitrification. Based on the evidence above, strain 3B26 T is considered to represent a novel species of the genus Shewanella , and the name Shewanella zhuhaiensis sp. nov. (type strain 3B26 T = GDMCC 1.2057 T = KCTC 82339 T ) is proposed.