Kaistella rhinocerotis sp. nov., isolated from the faeces of rhinoceros and reclassification of Chryseobacterium faecale as Kaistella faecalis comb. nov

Strain Ran72T, a novel Gram-stain-negative, obligately aerobic, non-motile, and rod-shaped bacterium, was isolated from the faeces of the rhinoceros species Ceratotherium simum. The novel bacterial strain grew optimally in Reasoner's 2A medium under the following conditions: 0 % (w/v) NaCl, pH 7.5, and 30 °C. Based on phylogenetic analysis using 16S rRNA gene sequencing, strain Ran72T was found to be most closely related to Chryseobacterium faecale F4T (98.4 %), Kaistella soli DKR-2T (98.0 %), and Kaistella haifensis H38T (97.4 %). A comprehensive genome-level comparison between strain Ran72T with C. faecale F4T, K. soli DKR-2T, and K. haifensis H38T revealed average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values of ≤74.9, ≤19.3, and ≤78.7 %, respectively. The major fatty acids were anteiso-C15 : 0 (22.3 %), with MK-6 being the predominant respiratory quinone. The major polar lipids of strain Ran72T were phosphatidylethanolamine, four unidentified aminolipids, and two unidentified lipids. Based on our chemotaxonomic, genotypic, and phenotype characterizations, strain Ran72T was identified as representing a novel species in the genus Kaistella, for which the name Kaistella rhinocerotis sp. nov. is proposed, with the type strain Ran72T (=KACC 23136T=JCM 36038T). Based on the outcomes of our phylogenomic study, Chryseobacterium faecale should be reclassified under the genus Kaistella as Kaistella faecalis comb. nov.

Chryseobacterium oryzae sp. nov. and Chryseobacterium suipulveris sp. nov., isolated from Andong sikhye and pigpen dust, respectively

Two Gram-stain-negative, aerobic, mesophilic, rod-shaped bacteria, ADR-1^T and SC2-2^T, were isolated from Andong sikhye and dust in a pigpen, respectively. The phylogenetic tree on the basis of 16S rRNA gene sequences showed that strains ADR-1^T and SC2-2^T were members of the genus Chryseobacterium and revealed the highest sequence similarities to Chryseobacterium binzhouense LM2^T (97.6 %) and Chryseobacterium koreense Chj707^T (94.9 %), respectively. Phylogenomic treeing using 92 core genes clearly indicated that strain ADR-1^T clustered with Chryseobacterium echinoideorum CC-CZW010^T, Chryseobacterium binzhouense LM2^T and Chryseobacterium taihuense CGMCC 1.10941^T, and strain SC2-2^T formed a compact cluster with Chryseobacterium koreense CCUG 49689^T. The digital DNA-DNA hybridization (dDDH) and orthologous average nucleotide identity (ANI) values of strain ADR-1^T with the closely related species of the genus Chryseobacterium were ≤24.4 % and ≤80.7 %, and those of strain SC2-2^T were ≤24.0 % and ≤77.8 %, respectively, which are well below the cut-off values of species discrimination (>70 % dDDH and >95-96 % ANI). The only respiratory quinone in both strains was menaquinone 6. The polar lipid profile of strain ADR-1^T comprised phosphatidylethanolamine, four unidentified aminolipids and three unidentified lipids, while strain SC2-2^T contained phosphatidylethanolamine, two unidentified aminolipids, one unidentified aminophospholipid and five unidentified polar lipids. The major fatty acids (>10 %) of strain ADR-1^T were iso-C_15 : 0, summed feature 9 (iso-C_17 : 1  ω9c and/or C_16 : 0 10-methyl), iso-C_17 : 0 3-OH and summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c), and those of strain SC2-2^T were iso-C_15 : 0 and anteiso-C_15 : 0. On the basis of the results of phenotypic and phylogenetic analyses, strains ADR-1^T and SC2-2^T represent two distinct novel species in the genus Chryseobacterium, for which the names Chryseobacterium oryzae sp. nov. (type strain ADR-1^T=KACC 19311^T=NBRC 113104^T) and Chryseobacterium suipulveris sp. nov. (type strain SC2-2^T=KACC 19313^T=NBRC 113106^T) are proposed.

Metabolic engineering for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose and propionic acid in recombinant Escherichia coli

In this study, novel polyhydroxyalkanoate (PHA)-associated genes (phaCp and phaABp) cloned from Propylenella binzhouense L72^T were expressed in Escherichiacoli cells for PHA production, and the recombinant strains were used to analyze PHA yields with various substrates. The highest poly (3-hydroxybutyrate-co-3-hydroxy-valerate) (PHBV) yield (1.06 g/L) and cell dry weight (3.31 g/L) in E. coli DH5α/ΔptsG-CpABp were achieved by using glucose and propionicacid as substrates. Structural verification of PHBV produced by E. coli DH5α/ΔptsG-CpABp was performed to evaluate the characteristics of the polymers using Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis. In addition, the X-ray diffraction results showed improved crystallinity of PHBV, and thermogravimetric analysis showed good thermal stability of 298 °C. The above findings indicated that the expression of phaCp and phaABp genes resulted in improved PHBV synthesis activity, and the polymer had better performance at higher processing temperatures.

Chryseobacterium schmidteae sp. nov. a novel bacterial species isolated from planarian Schmidtea mediterranea

Marseille-P9602T is a Chryseobacterium-like strain that we isolated from planarian Schmidtea mediterranea and characterized by taxono-genomic approach. We found that Marseille-P9602T strain exhibits a 16S rRNA gene sequence similarity of 98.76% with Chryseobacterium scophthalmum LMG 13028T strain, the closest phylogenetic neighbor. Marseille-P9602T strain was observed to be a yellowish-pigmented, Gram-negative, rod-shaped bacterium, growing in aerobic conditions and belonging to the Flavobacteriaceae family. The major fatty acids detected are 13-methyl-tetradecanoic acid (57%), 15-methylhexadecenoic acid (18%) and 12-methyl-tetradecanoic acid (8%). Marseille-P9602 strain size was found from genome assembly to be of 4,271,905 bp, with a 35.5% G + C content. The highest values obtained for Ortho-ANI and dDDH were 91.67% and 44.60%, respectively. Thus, hereby we unravel that Marseille-P9602 strain is sufficiently different from other closed related species and can be classified as a novel bacterial species, for which we propose the name of Chryseobacterium schmidteae sp. nov. Type strain is Marseille-P9602T (= CSUR P9602T = CECT 30295T).

Chelativorans alearense sp. nov., A Novel Bacterial Species Isolated From Soil in Alear, China

A novel Gram-strain-negative, rod-shaped, non-flagellated, non-gliding, beige-pigmented and aerobic bacterium, designated strain UJN715^T, was isolated from rhizosphere soil of Alhagi sparsifolia obtained from Alear city, located in Xinjiang province, PR China. Growth optimally occurred at 37 °C, pH 6.5-7.5, and 0-3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain UJN715^T belonged to the genus Chelativorans, with the highest sequence similarity to Chelativorans multitrophicus DSM 9103 ^T (97.7%). Genome sequencing revealed a genome size of 5 702 301 bp and a G + C content of 64.1 mol%. The ANI, POCP and the dDDH between strain UJN715^T and C. multitrophicus DSM 9103 ^T were 76.2%, 49.3%, and 20.5%, respectively. The prediction result of secondary metabolites based on genome showed that the strain UJN715^T contained one cluster of ectoine production, one cluster of non-ribosomal peptide synthetase (NRPS), one cluster of type I polyketide synthases (TIPKS), one cluster of bacteriocin, one cluster of TfuA-related, one cluster of N-acetylglutaminylglutamine amide (NAGGN) production, one cluster of terpene production, two clusters of homoserine lactone (Hserlactone) production. The major respiratory quinone was Q-10. The major fatty acids were iso-C_17:0, C_18:0 and C_19:0 cyclo ω8c and its polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phospholipids, unknown lipids, diphosphatidylglycerol, aminoglycolipid, unidentified aminophospholipids. On the basis of these data, strain UJN715^T is considered to represent a novel species of the genus Chelativorans, for which the name Chelativorans alearense sp. nov. is proposed. The type strain is UJN715^T (= KCTC 72856^T = CCTCC AB2019378^T).

Chryseobacterium cheonjiense sp. nov., isolated from forest soil

A yellow-pigmented, non-motile and rod-shaped bacterium, designated RJ-7-14^T was obtained from forest soil sampled at Cheonji-dong, Seogwipo-si, Jeju-do, South Korea. Cells were Gram-stain-negative and produced flexirubin type pigments. A phylogenetic analysis based on its 16S rRNA gene sequence revealed that strain RJ-7-14^T formed a lineage within the family Weeksellaceae and clustered as members of the genus Chryseobacterium. The closest members were Chryseobacterium geocarposphaerae DSM 27617^T (98.2% sequence similarity), Chryseobacterium hispalense DSM 25574^T (98.0%) and Chryseobacterium nepalense KACC 18907^T (98.0%). The sequence similarity for other members was < 98.0%. The genome was 4,276,416 bp long with 9 scaffolds and 3779 protein-coding genes. The sole respiratory quinone was MK-6. The major cellular fatty acids were iso-C_15:0, summed feature 9 (iso-C_17:1 ω9c and/or C_16:0 10-methyl), summed feature 3 (iso-C_15:0 2-OH and/or C_{16: 1}ω7c) and iso-C_17:0 3-OH. The major polar lipid was phosphatidylethanolamine (PE). The DNA G + C content of the type strain was 37.2 mol%. In addition, the average nucleotide identity (ANIu) and in silico DNA-DNA hybridization (dDDH) relatedness values between strain RJ-7-14^T and phylogenetically closest members were ≤ 88.2% and ≤ 35.0%, respectively, which were below the threshold values of 95-96% (for ANI) and 70% (for dDDH), suggesting the allocation of novel strain to a new species. Based on genomic, chemotaxonomic, phenotypic and phylogenetic analyses, strain RJ-7-14^T represents novel species in the genus Chryseobacterium, for which the name Chryseobacterium cheonjiense sp. nov. is proposed. The type strain is RJ-7-14^T (= KACC 21625^T = NBRC 114362^T).