Microbial community succession during the enrichment of crude-oil-degrading bacteria was analyzed using Illumina high-throughput sequencing to guide bacterial isolation and construction of a bacterial consortium. Community change occurred in 6 days; the most abundant phylum changed from Proteobacteria to Actinobacteria; the most abundant genera were Dietzia and unspecified_Idiomarinaceae. Two crude oil-degrading strains, Rhodococcus sp. OS62-1 and Dietzia sp. OS33, and one weak-crude-oil-degrading strain, Pseudomonas sp. P35, were isolated. A consortium comprising Rhodococcus sp. OS62-1 and Pseudomonas sp. P35 showed the highest crude-oil-degrading efficiency, reaching 85.72 ± 3.21% within 7 days, over a wide pH range (5–11) and salinity (0–80 g·L−1). Consumption of saturated hydrocarbons, aromatic hydrocarbons, and resins was greater by the consortium than by a single strain, as was degradation of short-chain-alkanes (C13–C17) according to gas-chromatography. The bacterial consortium provides technical support for bioremediation of crude oil pollution.

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An opaque, pink-colored, gram-positive, aerobic bacteria (designated FBM22-1T), 0.5 to 1.0 μm in width and 0.5 to 1.5 μm in length, was isolated from microbial fermentation bed material from a pig farm in northwestern China. Optimal growth occurred at 30–37℃, pH 7.0, and 0.5% NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the novel isolate belonged to the family Nocardiaceae of the class Actinomycetia. FBM22-1T is closely related to Rhodococcus zopfii NBRC 100606T and Rhodococcus rhodochrous NBRC 16069T, with 16S rRNA gene sequence similarity of 97.95% and 97.73%, respectively. The predominant respiratory quinone in FBM22-1T was ubiquinone MK-8(H2), and the cellular fatty acids consisted primarily of C16:1ω7c/16:1ω6c, C16:0, and C18:0 10-methly1. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and glycolipids. The G+C content of FBM22-1T was 68.64 mol%. Based on the phenotypic, phylogenetic, and chemotaxonomic characterization, in combination with low values of digital DNA–DNA hybridization between FBM22-1T and its closest neighbors, FBM22-1T represents a novel species of the genus Rhodococcus, for which the name Rhodococcus yananensis sp. nov. is proposed; the type strain is FBM22-1T (=KCTC 49502T = CCTCC 2020275T).