Nocardioides alcanivorans sp. nov., a novel hexadecane-degrading species isolated from plastic waste

Strain NGK65^T, a novel hexadecane degrading, non-motile, Gram-positive, rod-to-coccus shaped, aerobic bacterium, was isolated from plastic polluted soil sampled at a landfill. Strain NGK65^T hydrolysed casein, gelatin, urea and was catalase-positive. It optimally grew at 28 °C, in 0-1% NaCl and at pH 7.5-8.0. Glycerol, d-glucose, arbutin, aesculin, salicin, potassium 5-ketogluconate, sucrose, acetate, pyruvate and hexadecane were used as sole carbon sources. The predominant membrane fatty acids were iso-C_16:0 followed by iso-C_17:0 and C_18:1 ω9c. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and hydroxyphosphatidylinositol. The cell-wall peptidoglycan type was A3γ, with ll-diaminopimelic acid and glycine as the diagnostic amino acids. MK 8 (H₄) was the predominant menaquinone. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NGK65^T belongs to the genus Nocardioides (phylum Actinobacteria), appearing most closely related to Nocardioides daejeonensis MJ31^T (98.6%) and Nocardioides dubius KSL-104^T (98.3%). The genomic DNA G+C content of strain NGK65^T was 68.2%. Strain NGK65^T and the type strains of species involved in the analysis had average nucleotide identity values of 78.3-71.9% as well as digital DNA-DNA hybridization values between 22.5 and 19.7%, which clearly indicated that the isolate represents a novel species within the genus Nocardioides. Based on phenotypic and molecular characterization, strain NGK65^T can clearly be differentiated from its phylogenetic neighbours to establish a novel species, for which the name Nocardioides alcanivorans sp. nov. is proposed. The type strain is NGK65^T (=DSM 113112^T=NCCB 100846^T).