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

A rod-shaped, Gram-negative staining strain, FBM22 T , 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. FBM22-1 T 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. C 18:1 ω7c, C 16:1 ω7c and/ or C 16:1 ω6c, and C 14:0 2-OH were the major (≥ 8%) fatty acids. The G+C content was 56.8 mol%. FBM22 T 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 UI2 T (96.47%) and Sphingopyxis terrae subsp. terrae NBRC 15098 T (96.40%). Furthermore, FBM22 T had 18.7% and 18.4% relatedness (based on digital DNA-DNA hybridization) with its two relatives (S. terrae subsp. ummariensis UI2 T and S. terrae subsp. terrae NBRC 15098 T ). The morphological, physiological, and genotypic differences identified in this study support the classification of FBM22 T as a novel species within the genus Sphingopyxis, for which the name Sphingopyxis yananensis sp. nov. is proposed. The type strain is FBM22 T (= KCTC 82290 T  = CCTC AB2020286 T ).