Microbial exopolysaccharides (EPSs) have attracted attention from several fields due to their high industrial applicability. In the present study, rhizosphere strain CJ11T was isolated from the root of Glycine max L. in Goyang-si, Republic of Korea, and a novel exopolysaccharide was purified from the Lysobacter sp. CJ11T fermentation broth. The exopolysaccharide’s average molecular weight was 0.93 × 105 Da. Its monosaccharide composition included 72.2% mannose, 17.2% glucose, 7.8% galactose, and 2.8% arabinose. Fourier-transform infrared spectroscopy identified the exopolysaccharide carbohydrate polymer functional groups, and the structural properties were investigated using nuclear magnetic resonance. In addition, a microstructure of lyophilized EPS was determined by scanning electron microscopy. Using thermogravimetric analysis, the degradation of the exopolysaccharide produced by strain CJ11T was determined to be 210 °C. The exopolysaccharide at a concentration of 4 mg/mL exhibited 2,2-diphenyl-1-picrylhydrazyl free-radical-scavenging activity of 73.47%. Phylogenetic analysis based on the 16S rRNA gene sequencing results revealed that strain CJ11T was a novel isolate for which the name Lysobacter soyae sp. nov is proposed.

A multifunctional, Gram-stain-negative, aerobic, motile by flagella, short-rod shaped bacteria, designated strain RG36T was isolated from roots of marigold plant (Tagetes patula) sampled at Dongguk University, Republic of Korea. A 16S rRNA sequences indicated that the closest phylogenetic neighbors were Paraburkholderia acidiphila 7Q-K02T (99.0%) and Paraburkholderia sacchari IPT101T (98.9%) of the family Burkholderiaceae. The draft genome size was 8.52 Mb (63.7% GC). The genome contained 7,381 coding sequences. Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values of strain RG36T with its most closely related species were only 83.1–88.7 and 27.6–36.7%, respectively. Strain RG36T contained Q-8 as the major respiratory quinone and its main fatty acids (>10%) were C16:0, C17:0 cyclo, C19:0 cyclo ω8c, and summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c). Strain RG36T accumulates polyhydroxybutyrates (PHB) and exhibits multiple plant growth-promoting properties including production of indole-3-acetic acid (IAA), siderophores, protease, phosphate solubilization, and harboring gene clusters for its multifunctional properties. A pot experiment was conducted to evaluate the effect of PGPR on the growth of Solanum lycopersicum L. (Tomato). Result also confirmed the ability of strain RG36T to promote tomato plant growth, especially it increases the yield of tomatoes. Structural assessment of the bioplastic by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and GC-MS spectroscopy, which confirmed the structure of the polymer as PHB. Our study revealed the potential of strain RG36T to promote the growth of tomato plant and fruit yield by stimulating the various phytohormones, which could be use as bio-fertilizers to reduce the use of chemical fertilizers and promotes sustainable agricultural production. The phenotypic, chemotaxonomic and phylogenetic data, and genome analysis showed that strain RG36T represents a novel species of the genus Paraburkholderia, for which the name Paraburkholderia tagetis sp. nov. is proposed. The type strain is RG36T (=KACC 22685T = TBRC 15696T).

Two Gram-stain-negative, aerobic, yellow and rod-shaped bacteria, designated as strains PBS4-4T and GMJ5T, were isolated from soil samples collected in Goyang-si and Paju-si, Gyeonggi-do, Republic of Korea. Strains PBS4-4T and GMJ5T were both positive for catalase and oxidase. Strain PBS4-4T grew at 15–37 °C and pH 5.0–12.0. Strain GMJ5T grew at 15–37 °C and pH 5.0–11.0. Neither strain required NaCl for growth. 16S rRNA sequence analysis revealed that strains PBS4-4T and GMJ5T form a closely related cluster with the genus Chryseobacterium . The average nucleotide identity and digital DNA–DNA hybridization values between strain PBS4-4T and its closely related strains were 79.4–84.5% and 23.2–28.7 %, respectively. For GMJ5T, the values were 78.3–79.3% and 22.0–22.6 %, respectively. The major fatty acids shared by both novel strains were iso-C15 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). Strain GMJ5T had one other major fatty acid: iso-C17 : 0 3OH. Based on phenotypic, genomic and phylogenetic results, strains PBS4-4T and GMJ5T represent novel species within the genus Chryseobacterium , and the names Chryseobacterium edaphi sp. nov. and Chryseobacterium gilvum sp. nov. are proposed, respectively. The type strain of C. edaphi is PBS4-4T (=KACC 22882T=TBRC 17052T) and the type strain of C. gilvum is GMJ5T (=KACC 22883T=TBRC 17053T).

Gram-negative, aerobic, motile by means of two or more polar or subpolar flagella, rod-shaped strain NS12-5T and Gram-negative, facultatively anaerobic, yellow-coloured, rod-shaped strain RP8T were isolated from rice rhizosphere soil and fermented fruits of Liriope platyphylla in the Republic of Korea, respectively. The result of phylogenetic analyses based on 16S rRNA gene sequences showed that strain NS12-5T was most closely related to Ideonella aquatica 4Y11T with 99.79 % sequence similarity. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between strain NS12-5T and species of the genus Ideonella were 75.6–91.7 % and 20.3–43.9 %, respectively. Growth occurred at 15–40 °C and pH 5–11, and NaCl was not needed for growth. The major fatty acids of strain NS12-5T were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c) and C16 : 0, and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content of strain NS12-5T was 69.03 mol%. The result of phylogenetic analyses based on 16S rRNA gene sequences revealed that strain RP8T was most closely related to Spirosoma aureum BT328T with 96.01 % sequence similarity. The ANI and dDDH values between strain RP8T and reference strains of the genus Spirosoma were 72.9–76.4 % and 18.6–20.0 %, respectively. Growth occurred at 15–37 °C and pH 5–11, and NaCl was not needed for growth. The major fatty acids of strain RP8T were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 1 ω5c and iso-C15 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C contents of strain RP8T were 54.9 mol%. Based on phenotypic, genomic and phylogenetic results, strains NS12-5T and RP8T represent novel species in the genus Ideonella and Spirosoma , respectively, and the names Ideonella oryzae sp. nov. and Spirosoma liriopis sp. nov. are proposed. The type strain of I. oryzae sp. nov. is NS12-5T (=KACC 22691T=TBRC 16346T) and the type strain of S. liriopis is RP8T (=KACC 22688T=TBRC 16345T).

No abstract