Rhodococcus yananensis sp. nov., a novel denitrification actinobacterium isolated from microbial fermentation bed material from a pig farm.

An opaque, pink-coloured, gram-positive, aerobic bacteria (designated as FBM22-1T), was isolated from microbial fermentation bed material from a pig farm in northwestern China. Optimal growth occurred at 30-37 °C, pH 7.0 and with 0.5 % NaCl (w/v). The strain had nitrification and denitrification functions. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the novel isolate belonged to the genus Rhodococcus. Strain FBM22-1T was closely related to Rhodococcus zopfii NBRC 100606T and Rhodococcus rhodochrous NBRC 16069T, with 16S rRNA gene sequence similarities of 97.9 and 97.7 %, respectively. The predominant menaquinone in strain FBM22-1T was MK-8(H2). The cellular fatty acids consisted primarily of C16 : 1ω7c and/or C16 : 1 ω6c, C16 : 0 and 10-methyl C18 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and glycolipid. The G+C content of strain FBM22-1T was 68.64 mol%. Based on the phenotypic, phylogenetic and chemotaxonomic characterization results, in combination with low values of digital DNA-DNA hybridization between strain FBM22-1T and its closest neighbours, 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 AB2020275T).

Sphingopyxis yananensis sp. nov., a novel 2-nitropropane degrading bacterium isolated from a microbial fermentation bed substrate.

A rod-shaped, Gram-negative staining strain, FBM22T, was isolated from a microbial fermentation bed substrate from a pig farm. Its colonies appeared yellow and were 0.5-1.2 mm in diameter. Cells were 0.3-0.5 µm wide, 0.5-0.83 µm long. Optimal growth occurred at 30 °C and pH 7.0-8.0; NaCl was not required for growth. The strain performed denitrification and nitrate reduction functions. And it could produce catalase. FBM22-1T utilized the following organic substrates for growth: tyrosine, glutamic acid, D-glucose, and galactose. The novel isolate could degrade 2-nitropropane as carbon and nitrogen source. The dominant respiratory quinone was Q-10. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine and phosphatidylethanolamine. C18:1 ω7c, C16:1 ω7c and/ or C16:1 ω6c, and C14:0 2-OH were the major (≥ 8%) fatty acids. The G+C content was 56.8 mol%. FBM22T was found to be a member of the genus Sphingopyxis in the family Sphingomonadaceae of the class Alphaproteobacteria. It had the highest sequence similarity with the type strains Sphingopyxis terrae subsp. ummariensis UI2T (96.47%) and Sphingopyxis terrae subsp. terrae NBRC 15098T (96.40%). Furthermore, FBM22T had 18.7% and 18.4% relatedness (based on digital DNA-DNA hybridization) with its two relatives (S. terrae subsp. ummariensis UI2T and S. terrae subsp. terrae NBRC 15098T). The morphological, physiological, and genotypic differences identified in this study support the classification of FBM22T as a novel species within the genus Sphingopyxis, for which the name Sphingopyxis yananensis sp. nov. is proposed. The type strain is FBM22T (= KCTC 82290T = CCTC AB2020286T).