Mucilaginibacter Phenanthrenivorans sp. nov., a Novel Phenanthrene Degradation Bacterium Isolated from Wetland Soil

BJC16-A38^T, a Gram-negative, aerobic and non-motile rod-shaped strain was isolated from a permafrost wetland soil sample. BJC16-A38^T was oxidase- and catalase-positive, and produced pale yellow colonies on modified R2A agar plates. The 16S rRNA gene sequence of BJC16-A38^T shared the highest sequence similarity with those of Mucilaginibacter xinganensis BJC16-A31^T (97.44%), Mucilaginibacter gotjawali SA3-7^T (96.79%) and Mucilaginibacter frigoritolerans FT22^T (96.14%). Phylogenetic analysis revealed that BJC16-A38^T formed a separate lineage together with strain M. xinganensis BJC16-A31^T in the genus Mucilaginibacter. BJC16-A38^T contained menaquinone-7 (MK-7) as the predominant isoprenoid quinine. Major fatty acids in cells were iso-C_15:0, summed feature 3 (16:1ω7c/16:1ω6c) and iso-C_17:03-OH. BJC16-A38^T contained phosphatidylethanolamine, two unknown polar lipids, six unidentified phospholipids and an unidentified aminolipid. The Genome of BJC16-A38^T was sequenced using the Genome Analyzer IIx sequence platform and 38 contigs were produced in total with an average G + C percentage of 44.00%. The average nucleotide identity (ANI) of BJC16-A38^T with respect to those of M. xinganensis BJC16-A31^T, M. gotjawali SA3-7^T and M. frigoritolerans FT22^T were 79.60%, 77.24% and 77.58%, respectively. Digital DNA-DNA hybridization (DDH) values between BJC16-A38^T and the tree reference strains were 21.30%, 19.60% and 19.70%, respectively. BJC16-A38^T exhibited phenanthrene biodegradation activity that can degrade 88.02% phenanthrene in the MM medium after 7 days cultivation. Phenotypic, chemotaxonomic, phylogenetic and genomic characteristics concluded that strain BJC16-A38^T represents a novel species of the genus Mucilaginibacter. Hence, the name Mucilaginibacter phenanthrenivorans sp. nov. is proposed. The type strain is BJC16-A38^T (= CGMCC 1.12693^T = NBRC 110383^T).