Gordonia mangrovi sp. nov., a novel actinobacterium isolated from mangrove soil in Hainan

Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov., two novel actinobacteria isolated from mangrove sediments and leaves of halophyte Sesuvium portulacastrum in Thailand

A polyphasic approach was used to characterize two novel actinobacterial strains, designated PKS22-38T and LSe1-13T, which were isolated from mangrove soils and leaves of halophyte Sesuvium portulacastrum (L.), respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that they belonged to the genus Gordonia and were most closely related to three validly published species with similarities ranging from 98.6 to 98.1 %. The genomic DNA G+C contents of strains PKS22-38T and LSe1-13T were 67.3 and 67.2 mol%, respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 93.3 and 54.9 %, respectively, revealing that they are independent species. Meanwhile, the ANI and dDDH values between the two novel strains and closely related type strains were below 80.5 and 24.0 %, respectively. Strains PKS22-38T and LSe1-13T contained C16 : 0, C18 : 1  ω9c and C18 : 0 10-methyl (TBSA) as the major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as the main phospholipids. The predominant menaquinone was MK-9(H2). Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strains PKS22-38T and LSe1-13T are considered to represent two novel species within the genus Gordonia, for which the names Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov. are proposed, with strain PKS22-38T (=TBRC 17540T=NBRC 116256T) and strain LSe1-13T (=TBRC 17706T=NBRC 116396T) as the type strains, respectively.

Gordonia tangerina sp. nov., isolated from seawater

A Gram-stain-positive, aerobic bacterium, designated GW1C4-4^T, was isolated from the seawater sample from the tidal zone of Guanyinshan Coast, Xiamen, Fujian Province, PR China. The strain was reddish-orange, rod-shaped and non-motile. Cells of strain GW1C4-4^T were oxidase-negative and catalase-positive. The strain could grow at 10-42 °C (optimum, 32-35 °C), pH 5-9 (optimum, pH 6) and with 0-10 % NaCl (w/v; optimum, 1 %). Phylogenetic analysis based on the 16S rRNA sequences indicated that strain GW1C4-4^T belonged to the genus Gordonia, having the highest similarity to Gordonia mangrovi HNM0687^T (98.5 %), followed by Gordonia bronchialis DSM 43247^T (98.4 %). The G+C DNA content was 66.5 mol %. Average nucleotide identity and digital DNA-DNA hybridization values between strain GW1C4-4^T and G. mangrovi HNM0687^T were 85.8 and 30.0 %, respectively. The principal fatty acids of strain GW1C4-4^T were C_16 : 0, C_18 : 0 10-methyl (TBSA) and summed feature 3 (C_16 : 1  ω7c/C_16 : 1  ω6c). MK-9 (H₂) was the sole respiratory quinone. The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified lipid. Based on its phylogenetic, phenotypic, chemotaxonomic and genomic characteristics, it is proposed that strain GW1C4-4^T represents a novel species within the genus Gordonia, for which the name Gordonia tangerina sp. nov. is proposed. The type strain is GW1C4-4^T (=MCCC 1A18727^T=KCTC 49729^T).

Gordonia pseudamarae sp. nov., a home for novel actinobacteria isolated from stable foams on activated sludge wastewater treatment plants

The taxonomic status of two Gordonia strains, designated BEN371 and CON9T, isolated from stable foams on activated sludge plants was the subject of a polyphasic study which also included the type strains of Gordonia species and three authenticated Gordonia amarae strains recovered from such foams. Phylogenetic analyses of 16S rRNA gene sequences showed that these isolates formed a compact cluster suggesting a well-supported lineage together with a second branch containing the G. amarae strains. A phylogenomic tree based on sequences of 92 core genes extracted from whole genome sequences of the isolates, the G. amarae strains and Gordonia type strains confirmed the assignment of the isolates and the G. amarae strains to separate but closely associated lineages. Average nucleotide index (ANI) and digital DNA–DNA hybridisation (dDDH) similarities showed that BEN371 and CON9T belonged to the same species and had chemotaxonomic and morphological features consistent with their assignment to the genus Gordonia . The isolates and the G. amarae strains were distinguished using a range of phenotypic features and by low ANI and dDDH values of 84.2 and 27.0 %, respectively. These data supplemented with associated genome characteristics show that BEN371 and CON9T represent a novel species of the genus Gordonia . The name proposed for members of this taxon is Gordonia pseudamarae sp. nov. with isolate CON9T (=DSM 43602T=JCM 35249T) as the type strain.

Gordonia sp. BSTG01 isolated from Hevea brasiliensis plantation efficiently degrades polyisoprene (rubber)

Polyisoprene is the principal constituent of rubber latex which has been estimated globally as one of the major solid wastes. Bacterial bioremediation of this solid waste remains a major point of interest for scientists. This study reports a Gram-positive, non-motile, non-spore-forming actinomycete Gordonia sp. BSTG01, isolated from the bark of Hevea brasiliensis of a rubber plantation garden can considerably degrade natural rubber (NR) and synthetic polyisoprene rubber (SR). Scanning electron microscopy showed adhesive colonization of strain BSTG01 on both natural and synthetic rubber surface, conflating into the rubber and forming a biofilm. Rubber-dependent growth of the strain was examined by the decrease of rubber mass and increase of its total protein content in a time-dependent manner. Degradation was also verified by Schiff's reagent which confirms the appearance of aldehydes in the culture media. Fourier transform infrared spectroscopy including the attenuated total reflectance with the NR and SR pieces overgrown by the isolate revealed variations of the overall chemicals arising on the polyisoprene backbone due to the degradation of rubber by the strain BSTG01. Isolate BSTG01 (MTCC 13159) is a strain of Gordonia and this is the first strain isolated from unexplored rubber plantation area with considerable rubber degradation properties.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-03063-5.