Refermentation and maturation of lambic beer in bottles: a necessary step for gueuze production.

The production of gueuze beers through refermentation and maturation of blends of lambic beer in bottles is a way for lambic brewers to cope with the variability among different lambic beer batches. The resulting gueuze beers are more carbonated than lambic beers and are supposed to possess a unique flavor profile that varies over time. To map this refermentation and maturation process for gueuze production, a blend of lambic beers was made and bottled, whereby one of them was produced with the old wheat landrace Zeeuwse Witte. Through the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and high-throughput sequencing of bacterial and fungal amplicons, in combination with metabolite target analysis, new insights into gueuze production were obtained. During the initial stages of refermentation, the conditions in the bottles were similar to those encountered during the maturation phase of lambic beer productions in wooden barrels, which was also reflected microbiologically (presence of Brettanomyces species, Pediococcus damnosus, and Acetobacter lambici) and biochemically (ethanol, higher alcohols, lactic acid, acetic acid, volatile phenolic compounds, and ethyl esters). However, after a few weeks of maturation, a switch from a favorable environment to one with nutrient and dissolved oxygen depletion resulted in several changes. Concerning the microbiology, a sequential prevalence of three lactic acid bacterial species occurred, namely, P. damnosus, Lentilactobacillus buchneri, and Lactobacillus acetotolerans, while the diversity of the yeasts decreased. Concerning the metabolites produced, mainly those of the Brettanomyces yeasts determined the metabolic profiles encountered during later stages of the gueuze production.IMPORTANCEGueuze beers are the result of a refermentation and maturation process of a blend of lambic beers carried out in bottles. These gueuze beers are known to have a long shelf life, and their quality typically varies over time. However, knowledge about gueuze production in bottles is scarce. The present study provided more insights into the varying microbial and metabolite composition of gueuze beers during the first 2 years of this refermentation and maturation process. This will allow gueuze producers to gain more information about the influence of the refermentation and maturation time on their beers. These insights can also be used by gueuze producers to better inform their customers about the quality of young and old gueuze beers.

Pseudomonas fortuita sp. nov., isolated from the endosphere of a wild yam.

A Gram-negative, strictly aerobic bacterial strain was isolated from asymptomatic leaf tissue of a wild yam plant. Optimal growth was observed at 28 °C and pH 7, and catalase and oxidase activities were detected. Polyphasic taxonomic and comparative genomics revealed that strain LMG 33091T represents a novel species of Pseudomonas. The nearest phylogenetic neighbours of strain LMG 33091T were Pseudomonas putida NBRC 14164T (with 99.79 % 16S rRNA sequence identity), Pseudomonas alkylphenolica KL28T (99.28 %) and Pseudomonas asplenii (99.07 %) ATCC 23835T. MALDI-TOF MS analysis yielded distinct profiles for strain LMG 33091T and the nearest phylogenetic neighbours. Average nucleotide identity analyses between the whole genome sequence of strain LMG 33091T and of the type strains of its nearest-neighbour taxa yielded values below the species delineation threshold and thus confirmed that the strain represented a novel Pseudomonas species, for which we propose the name Pseudomonas fortuita sp. nov., with strain LMG 33091T (=GMI12077T= CFBP 9143T) as the type strain.

Proposal of Helicobacter higonensis sp. nov. isolated from a human clinical specimen, and emended description of Helicobacter valdiviensis Collado, 2014.

We have previously isolated a gram-negative microaerophilic strain, PAGU2000T from a patient presenting with a fever in Kumamoto Prefecture, Japan. The present study aimed to comprehensively analyze the taxonomy of the isolated strain using a polyphasic approach. The 16S rRNA gene sequence analysis indicated that the strain was a member of enterohepatic Helicobacter. The strain PAGU2000T shared a 97.5% 16S rRNA gene nucleotide identity with Helicobacter valdiviensis, and this taxonomic position was confirmed by phylogenetic analysis of the GyrA amino acid sequences. The proposed strain PAGU2000T has a 1.482 Mbp chromosome with a DNA G + C content of 31.3 mol% and encodes 1520 predicted coding sequences. The average nucleotide identity between the strain PAGU2000T and type strain of H. valdiviensis was 70.3%, which was lower than the recommended threshold of 95% for species delineation. The strain PAGU2000T was a motile, non-spore-forming, and spiral-shaped bacterium, exhibiting catalase and oxidase activities but not urease and nitrate reduction. This study demonstrates that the isolate represents a novel species within enterohepatic Helicobacter, for which the name Helicobacter higonensis is proposed (type strain: PAGU2000T = GTC 16811T = LMG 33095T). In this study, we describe the phenotypic and morphological features of this strain and propose an emended description of some biochemical traits of H. valdiviensis.

Comparative genomic analysis of Periweissella and the characterization of novel motile species.

The genus Periweissella was proposed as a novel genus in the Lactobacillaceae in 2022. However, the phylogenetic relationship between Periweissella and other heterofermentative lactobacilli, and the genetic and physiological properties of this genus remain unclear. This study aimed to determine the phylogenetic relationship between Periweissella and the two closest genera, Weissella and Furfurilactobacillus, by the phylogenetic analysis and calculation of (core gene) pairwise average amino acid identity. Targeted genomic analysis showed that fructose bisphosphate aldolase was only present in the genome of Pw. cryptocerci. Mannitol dehydrogenase was found in genomes of Pw. beninensis, Pw. fabaria, and Pw. fabalis. Untargeted genomic analysis identified the presence of flagellar genes in Periweissella but not in other closely related genera. Phenotypes related to carbohydrate fermentation and motility matched the genotypes. Motility genes were organized in a single operon and the proteins shared a high amino acid similarity in the genus Periweissella. The relatively low similarity of motility operons between Periweissella and other motile lactobacilli indicated the acquisition of motility by the ancestral species. Our findings facilitate the phylogenetic, genetic, and phenotypic understanding of the genus Periweissella.ImportanceThe genus Periweissella is a heterofermentative genus in the Lactobacillaceae which includes predominantly isolates from cocoa fermentations in tropical climates. Despite the relevance of the genus in food fermentations, genetic and physiological properties of the genus are poorly characterized and genome sequences became available only after 2020. This study characterized strains of the genus by functional genomic analysis, and by determination of metabolic and physiological traits. Phylogenetic analysis revealed that Periweissella is the evolutionary link between rod-shaped heterofermentative lactobacilli and the coccoid Leuconostoc clade with the genera Weissella and Furfurilactobacillus as closest relatives. Periweissella is the only heterofermentative genus in the Lactobacillaceae which comprises predominantly motile strains. The genomic, physiological, and metabolic characterization of Periweissella may facilitate the potential use of strains of the genus as starter culture in traditional or novel food fermentations.

Convivina is a specialised core gut symbiont of the invasive hornet Vespa velutina.

We provide a culturomics analysis of the cultivable bacterial communities of the crop, midgut and hindgut compartments, as well as the ovaries, of the invasive insect Vespa velutina, along with a cultivation-independent analysis of samples of the same nest through 16S rRNA amplicon sequencing. The Vespa velutina bacterial symbiont community was dominated by the genera Convivina, Fructobacillus, Lactiplantibacillus, Lactococcus, Sphingomonas and Spiroplasma. Lactococcus lactis and Lactiplantibacillus plantarum represented generalist core lactic acid bacteria (LAB) symbionts, while Convivina species and Fructobacillus fructosus represented highly specialised core LAB symbionts with strongly reduced genome sizes. Sphingomonas and Spiroplasma were the only non-LAB core symbionts but were not isolated. Convivina bacteria were particularly enriched in the hornet crop and included Convivina intestini, a species adapted towards amino acid metabolism, and Convivina praedatoris sp. nov. which was adapted towards carbohydrate metabolism.

The wild solitary bees Andrena vaga, Anthophora plumipes, Colletes cunicularius, and Osmia cornuta microbiota are host specific and dominated by endosymbionts and environmental microorganisms.

We characterized the microbial communities of the crop, midgut, hindgut, and ovaries of the wild solitary bees Andrena vaga, Anthophora plumipes, Colletes cunicularius, and Osmia cornuta through 16S rRNA gene and ITS2 amplicon sequencing and a large-scale isolation campaign. The bacterial communities of these bees were dominated by endosymbionts of the genera Wolbachia and Spiroplasma. Bacterial and yeast genera representing the remaining predominant taxa were linked to an environmental origin. While only a single sampling site was examined for Andrena vaga, Anthophora plumipes, and Colletes cunicularius, and two sampling sites for Osmia cornuta, the microbiota appeared to be host specific: bacterial, but not fungal, communities generally differed between the analyzed bee species, gut compartments and ovaries. This may suggest a selective process determined by floral and host traits. Many of the gut symbionts identified in the present study are characterized by metabolic versatility. Whether they exert similar functionalities within the bee gut and thus functional redundancy remains to be elucidated.

Description of Pseudoclavibacter triregionum sp. nov. from human blood and Pseudoclavibacter albus comb. nov., and revised classification of the genus Pseudoclavibacter: proposal of Caespitibacter gen. nov., with Caespitibacter soli comb. nov. and Caespitibacter caeni comb. nov.

We present polyphasic taxonomic data to demonstrate that strain 125703-2019T, a human blood isolate, represents a novel species within the genus Pseudoclavibacter, and to reclassify the illegitimate Zimmermannella alba Lin et al., 2004 as Pseudoclavibacter albus comb. nov. Upon primary isolation, strain 125703-2019T could not be identified reliably using MALDI-TOF mass spectrometry during routine diagnostic work, but partial 16S rRNA gene sequence analysis revealed that it belonged to the genus Pseudoclavibacter. Average nucleotide identity and digital DNA-DNA hybridisation analyses confirmed that it represented a novel species within this genus. A detailed physiological characterisation yielded differential tests between the novel species and its nearest neighbor taxa, which could also be differentiated using MALDI-TOF mass spectrometry. We propose to formally classify this strain into the novel species Pseudoclavibacter triregionum sp. nov., with strain 125703-2019T (= R-76471T, LMG 31777T, CCUG 74796T) as the type strain. The whole-genome assembly of strain 125703-2019T has a size of 2.4 Mb and a G + C content of 72.74%. A Pseudoclavibacter pangenome analysis revealed that 667 gene clusters were exclusively present in strain 125703-2019T. While these gene clusters were enriched in several COG functional categories, this analysis did not reveal functions that explained the occurrence of this species in human infection. Finally, several phylogenetic and phylogenomic analyses demonstrated that the genus Pseudoclavibacter is polyphyletic with Pseudoclavibacter soli and Pseudoclavibacter caeni representing a unique and deeply branching line of descent within the family Microbacteriaceae. We therefore also propose to reclassify both species into the novel genus Caespitibacter gen. nov. as Caespitibacter soli comb. nov. and Caespitibacter caeni comb. nov., respectively, and with C. soli comb. nov. as the type species.

Induction of antibiotic specialized metabolism by co-culturing in a collection of phyllosphere bacteria.

A diverse set of bacteria live on the above-ground parts of plants, composing the phyllosphere, and play important roles for plant health. Phyllosphere microbial communities assemble in a predictable manner and diverge from communities colonizing other plant organs or the soil. However, how these communities differ functionally remains obscure. We assembled a collection of 258 bacterial isolates representative of the most abundant taxa of the phyllosphere of Arabidopsis and a shared soil inoculum. We screened the collection for the production of metabolites that inhibit the growth of Gram-positive and Gram-negative bacteria either in isolation or in co-culture. We found that isolates capable of constitutive antibiotic production in monoculture were significantly enriched in the soil fraction. In contrast, the proportion of binary cultures resulting in the production of growth inhibitory compounds differed only marginally between the phyllosphere and soil fractions. This shows that the phyllosphere may be a rich resource for potentially novel molecules with antibiotic activity, but that production or activity is dependent upon induction by external signals or cues. Finally, we describe the isolation of antimicrobial acyloin metabolites from a binary culture of Arabidopsis phyllosphere isolates, which inhibit the growth of clinically relevant Acinetobacter baumannii.

Paenibacillus foliorum sp. nov., Paenibacillus phytohabitans sp. nov., Paenibacillus plantarum sp. nov., Paenibacillus planticolens sp. nov., Paenibacillus phytorum sp. nov. and Paenibacillus germinis sp. nov., isolated from the Arabidopsis thaliana phyllosphere.

Six endospore-forming, Gram-stain-positive or variable, motile, rod-shaped, aerobic or facultatively anaerobic bacteria with different MALDI-TOF mass spectra (MS) were isolated from the phyllosphere of Arabidopsis thaliana plants grown in plant chambers after inoculation of surface sterilized seeds with a top soil microbial cell suspension. They were identified as members of the genus Paenibacillus through comparison with a commercial MALDI-TOF MS database and comparative 16S rRNA gene sequencing. Their genome sequences comprised multiple biosynthetic gene clusters and suggested they have unexplored biotechnological potential. Analyses of average nucleotide identity values between these strains and the type strains of their nearest neighbour species demonstrated that they represented a novel Paenibacillus species each. A detailed phenotypic comparison yielded distinctive biochemical characteristics for each of these novel species. We therefore propose to classify that these isolates into six novel species within genus Paenibacillus, for which we propose the names Paenibacillus foliorum sp. nov., Paenibacillus phytohabitans sp. nov., Paenibacillus plantarum sp. nov., Paenibacillus planticolens sp. nov., Paenibacillus phytorum sp. nov. and Paenibacillus germinis sp. nov., with strains LMG 31456T (=R-74617T=CECT 30138T), LMG 31459T (=R-74621T=CECT 30135T), LMG 31461T (=R-74618T=CECT 30133T), LMG 31457T (=R-74619T=CECT 30137T), LMG 31458T (=R-74620T=CECT 30136T) and LMG 31460T (=R-74622T=CECT 30134T) as the type strains, respectively.

Gluconacetobacter dulcium sp. nov., a novel Gluconacetobacter species from sugar-rich environments.

A phylogenomic analysis based on 107 single-copy core genes revealed that three strains from sugar-rich environments, i.e. LMG 1728T, LMG 1731 and LMG 22058, represented a single, novel Gluconacetobacter lineage with Gluconacetobacter liquefaciens as nearest validly named neighbour. OrthoANIu and digital DNA-DNA hybridization analyses among these strains and Gluconacetobacter type strains confirmed that the three strains represented a novel Gluconacetobacter species. Biochemical characteristics and MALDI-TOF mass spectra allowed differentiation of this novel species from the type strains of G. liquefaciens and other closely related Gluconacetobacter species. We therefore propose to classify strains LMG 1728T, LMG 1731 and LMG 22058 in the novel species Gluconacetobacter dulcium sp. nov., with LMG 1728T (=CECT 30142T) as the type strain.

Gulosibacter hominis sp. nov.: a novel human microbiome bacterium that may cause opportunistic infections.

We present genomic, phylogenomic, and phenotypic taxonomic data to demonstrate that three human ear isolates represent a novel species within the genus Gulosibacter. These isolates could not be identified reliably using MALDI-TOF mass spectrometry during routine diagnostic work, but partial 16S rRNA gene sequence analysis revealed that they belonged to the genus Gulosibacter. Overall genomic relatedness indices between the draft genome sequences of the three isolates and of the type strains of established Gulosibacter species confirmed that the three isolates represented a single novel Gulosibacter species. A biochemical characterisation yielded differential tests between the novel and established Gulosibacter species, which could also be differentiated using MALDI-TOF mass spectrometry. We propose to formally classify these three isolates into Gulosibacter hominis sp. nov., with 401352-2018 T (= LMG 31778 T, CCUG 74795 T) as the type strain. The whole-genome sequence of strain 401352-2018 T has a size of 2,340,181 bp and a G+C content of 62.04 mol%. A Gulosibacter pangenome analysis revealed 467 gene clusters that were exclusively present in G. hominis genomes. While these G. hominis specific gene clusters were enriched in several COG functional categories, this analysis did not reveal functions that suggested a role in the human microbiome, nor did it explain the occurrence of G. hominis in ear infections. The absence of acquired antimicrobial resistance determinants and virulence factors in the G. hominis genomes, and an analysis of publicly available 16S rRNA gene sequences and 16S rRNA amplicon sequencing data sets suggested that G. hominis is a member of the human skin microbiota that may occasionally be involved in opportunistic infections.

Novel acetic acid bacteria from cider fermentations: Acetobacter conturbans sp. nov. and Acetobacter fallax sp. nov.

Strains LMG 1627T, LMG 1636T and LMG 1637 were all isolated from cider fermentations in the 1940s and 1950s. A recent study based on MALDI-TOF MS and dnaK gene sequence analyses suggested they represented novel Acetobacter species. In the present study, we determined the whole-genome sequences of these strains and analysed their phenotypic and chemotaxonomic characteristics. A phylogenomic analysis based on 107 single-copy core genes revealed that they represented a single Acetobacter lineage with Acetobacter aceti, Acetobacter sicerae, Acetobacter musti and Acetobacter oeni, Acetobacter estunensis and with Acetobacter nitrogenifigens as an outgroup to this cluster. OrthoANIu value and dDDH analyses among these and other Acetobacter type strains confirmed that these three strains represented two novel Acetobacter species, which could be differentiated from other closely related type strains of Acetobacter by different phenotypic tests, such as ketogenesis from glycerol. We therefore propose to classify strain LMG 1627T in the novel species Acetobacter conturbans sp. nov., with LMG 1627T (=NCIMB 8945T) as the type strain, and to classify strains LMG 1636T and LMG 1637 in the novel species Acetobacter fallax sp. nov., with LMG 1636T (=NCIMB 8956T) as the type strain.

Achromobacter veterisilvae sp. nov., from a mixed hydrogen-oxidizing bacteria enrichment reactor for microbial protein production.

Strain LMG 30378T was isolated from a hydrogen-oxidizing bacteria enrichment reactor inoculated with forest soil. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that this strain belonged to the genus Achromobacter. Multilocus sequence analysis combined with sequence analysis of a 765 bp nrd A gene fragment both showed Achromobacter agilis LMG 3411T and Achromobacter denitrificans LMG 1231T to be the closest-related neighbours to strain LMG 30378T. Genome sequence analysis revealed a draft genome of 6.81 Mb with a G+C content of 67.2 mol%. In silico DNA-DNA hybridization with A. denitrificans LMG 1231T and A. agilis LMG 3411T showed 42.7 and 42.5% similarity, respectively, confirming that strain LMG 30378T represented a novel Achromobacter species. Phenotypic and metabolic characterization revealed acid phosphatase activity and the absence of phosphoamidase activity as distinctive features. The draft genome composes all necessary metabolic components to fix carbon dioxide and to oxidize molecular hydrogen, suggesting that strain LMG 30378T is a key organism in the enrichment reactor. Together, these data demonstrate that strain LMG 30378T represents a novel species of the genus Achromobacter, for which the name Achromobacter veterisilvae sp. nov. is proposed. The type strain is LMG 30378T (=CCUG 71558T).

Pedobacter gandavensis sp. nov., Pedobacter foliorum sp. nov. and Pedobacter planticolens sp. nov., isolated from leaves of Arabidopsis thaliana.

Three rod-shaped, non-spore-forming, yellow or pale-yellow pigmented bacteria with distinct MALDI-TOF mass spectra were isolated from the phyllosphere of Arabidopsis thaliana seedlings. Their 16S rRNA gene sequences demonstrated that these isolates belong to the genus Pedobacter. The nearest phylogenetic neighbours of strain LMG 31462T were Pedobacter steynii DSM 19110T (98.3 % 16S rRNA sequence similarity) and Pedobacter caeni LMG 22862T (98.3 %); the nearest phylogenetic neighbours of strain LMG 31463T were Pedobacter panaciterrae Gsoil 042T (98.3 %) and Pedobacter nutrimenti DSM 27372T (98.1 %); and the nearest phylogenetic neighbours of strain LMG 31464T were Pedobacter boryungensis BR-9T (99.0 %) and Pedobacter daejeonensis THG-DN3.18T (98.7 %). Average nucleotide identity analyses between the whole genome sequences of the three strains and of the type strains of their respective nearest-neighbour taxa yielded values well below the species delineation threshold and thus confirmed that the three strains represented a novel Pedobacter species each. An extensive phenotypic comparison and an analysis of whole-cell fatty acid components yielded distinctive phenotypic characteristics for each of these strains. We therefore propose to classify these isolates as three novel species, for which we propose the names Pedobacter gandavensis with LMG 31462T (=R-74704T=CECT 30149T) as the type strain, Pedobacter foliorum with LMG 31463T (=R-74623T=CECT 30150T) as the type strain and Pedobacter planticolens with LMG 31464T (=R-74626T=CECT 30151T) as the type strain.

Characterization of novel Gluconobacter species from fruits and fermented food products: Gluconobacter cadivus sp. nov., Gluconobacter vitians sp. nov. and Gluconobacter potus sp. nov.

Strains LMG 1744T, LMG 1745, LMG 31484T, LMG 1764T and R-71646 were isolated from rotting fruits and fermented food products. A phylogenomic analysis based on 107 single-copy core genes revealed that they grouped in a Gluconobacter lineage comprising Gluconobacter oxydans, Gluconobacter roseus, Gluconobacter sphaericus, Gluconobacter kanchanaburiensis, Gluconobacter albidus, Gluconobacter cerevisiae, Gluconobacter kondonii and Gluconobacter aidae. OrthoANIu and digital DNA hybridization analyses demonstrated that these five strains represented three novel Gluconobacter species, which could be differentiated from the type strains of closely related Gluconobacter species by multiple phenotypic characteristics. We therefore propose to classify strains LMG 1744T and LMG 1745 in the novel species Gluconobacter cadivus sp. nov., with LMG 1744T (=CECT 30141T) as the type strain; to classify strain LMG 31484T as the novel species Gluconobacter vitians sp. nov., with LMG 31484T (=CECT 30132T) as the type strain; and to classify strains LMG 1764T and R-71646 in the novel species Gluconobacter potus sp. nov., with LMG 1764T (=CECT 30140T) as the type strain.

Symbiotic and non-symbiotic Paraburkholderia isolated from South African Lebeckia ambigua root nodules and the description of Paraburkholderia fynbosensis sp. nov.

Nine Gram-negative, rod-shaped bacteria were isolated from Lebeckia ambigua root nodules. All strains were able to nodulate and fix nitrogen with Lebeckia ambigua apart from WSM4178T, WSM4181 and WSM4182. Based on the 16S rRNA gene phylogeny, all strains were closely related to Paraburkholderia species (98.4-99.9 %), belonging to the Betaproteobacteria class and Burkholderiaceae family. According to 16S rRNA gene phylogeny the closest relative for WSM4174-WSM4177 and WSM4179-WSM4180 was Paraburkholderia tuberum(99.80-99.86 %), for WSM4178T was Paraburkholderia caledonica (98.42 %) and for WSM4181-WSM4182 was Paraburkholderia graminis (99.79 %). Analysis of the gyrB and recA housekeeping genes supported the assignment of WSM4181-WSM4182 to P. graminis and the other investigated strains could be assigned to the genus Paraburkholderia. The results of DNA-DNA hybridization, physiological and biochemical tests allowed genotypic and phenotypic differentiation of WSM4178T from the closest validly published Paraburkholderia species. However, WSM4174-WSM4177 and WSM4179-WSM4180 could not reliably be distinguished from its closest neighbour and therefore complete genome comparison was performed between WSM4176 and P. tuberum STM678T which gave ANI values of 96-97 %. Chemotaxonomic data, including fatty acid profiles and quinone data supported the assignment of the strains to the genus Paraburkholderia. On the basis of genotypic and phenotypic data one novel species, Paraburkholderiafynbosensis sp. nov. (WSM4178T=LMG 27177T=HAMBI 3356T), is proposed and the isolation of P. tuberum and P. graminis from root nodules of Lebeckia ambigua is reported.

Halomonas nigrificans sp. nov., isolated from cheese.

A Gram-stain-negative, rod-shaped Proteobacteria isolate, MBT G8648T, was obtained from an acid curd cheese called Quargel. The isolate was moderately salt tolerant and motile, with numerous peritrichous flagella. The 16S rRNA gene sequence analysis indicated that the strain belongs to the genus Halomonas, with 98.42 % 16S rRNA gene sequence similarity with Halomonas titanicae BH1T as nearest related neighbour. Further comparative sequence analysis of secA and gyrB genes, as well as physiological and biochemical tests, revealed that this bacterium formed a taxon well-separated from its nearest neighbours and other established Halomonas species. Thus, the strain represents a new species, for which the name Halomonas nigrificans sp. nov. is proposed, with strain MBT G8648T (=LMG 29097T =DSM 105749T) as type strain.

Paraburkholderia piptadeniae sp. nov. and Paraburkholderia ribeironis sp. nov., two root-nodulating symbiotic species of Piptadenia gonoacantha in Brazil.

During a survey of root-nodulating symbionts of Mimosoid species in the south-east region of Brazil, eight Paraburkholderia isolates were obtained from nodules of the legume species Piptadenia gonoacantha, either from the field or following a soil trapping method with the same plant host. 16S rRNA gene as well as recA and gyrB phylogenetic markers placed these strains in two new clades within the genus Burkholderia sensu lato. DNA-DNA hybridization values and analyses of average nucleotide identities of the whole genome sequence of selected strains in each clade (STM 7183 and STM 7296) showed that the two clades represented novel species of the genus Paraburkholderia. All eight isolates were further characterized using DNA base content determination, chemotaxonomic and biochemical profiling and symbiotic properties, which allowed to distinguish the novel species from known diazotrophic species of the genus Paraburkholderia. Based on genomic and phenotypic data, the names Paraburkholderia piptadeniae sp. nov. with type strain STM 7183T (=DSM 101189T=LMG 29163T) and Paraburkholderia ribeironis sp. nov. with type strain STM 7296T (=DSM 101188T=LMG 29351T) are proposed.

Pedobacter jamesrossensis sp. nov., Pedobacter lithocola sp. nov., Pedobacter mendelii sp. nov. and Pedobacter petrophilus sp. nov., isolated from the Antarctic environment.

A taxonomic study performed on 17 Gram-stain-negative rod-shaped bacterial strains originating from the Antarctic environment is described. Initial phylogenetic analysis using 16S rRNA gene sequencing differentiated the strains into four groups belonging to the genus Pedobacter but they were separated from all hitherto described Pedobacter species. Group I (n=8) was closest to Pedobacter aquatilis (97.8 % 16S rRNA gene sequence similarity). Group II (n=2) and group III (n=4) were closely related (98.8 % 16S rRNA gene sequence similarity) and had Pedobacter jejuensis as their common nearest neighbour. Group IV (n=3) was distantly delineated from the remaining Pedobacter species. Differentiation of the analysed strains into four clusters was further confirmed by repetitive sequence-based PCR fingerprinting, ribotyping, DNA-DNA hybridization and phenotypic traits. Common to representative strains for the four groups were the presence of major menaquinone MK-7, sym-homospermidine as the major polyamine, phosphatidylethanolamine, two unidentified lipids (L2, L5) and an unidentified aminolipid (AL2) as the major polar lipids, presence of an alkali-stable lipid, and C16:1ω7c/C16:1ω6c (summed feature 3), iso-C15:0 and iso-C 17:0 3-OH as the major fatty acids, which corresponded to characteristics of the genus Pedobacter. The obtained results showed that the strains analysed represent four novel species of the genus Pedobacter, for which the names Pedobacter jamesrossensis sp. nov. (type strain CCM 8689T=LMG 29684T), Pedobacter lithocola sp. nov. (CCM 8691T=LMG 29685T), Pedobacter mendelii sp. nov. (CCM 8685T=LMG 29688T) and Pedobacter petrophilus sp. nov. (CCM 8687T=LMG 29686T) are proposed.

Bifidobacterium aquikefiri sp. nov., isolated from water kefir.

A novel Bifidobacterium, strain LMG 28769T, was isolated from a household water kefir fermentation process. Cells were Gram-stain-positive, non-motile, non-spore-forming, catalase-negative, oxidase-negative and facultatively anaerobic short rods. Analysis of its 16S rRNA gene sequence revealed Bifidobacterium crudilactis and Bifidobacterium psychraerophilum (97.4 and 97.1 % similarity towards the respective type strain sequences) as nearest phylogenetic neighbours. Its assignment to the genus Bifidobacterium was confirmed by the presence of fructose 6-phosphate phosphoketolase activity. Analysis of the hsp60 gene sequence revealed very low similarity with nucleotide sequences in the NCBI nucleotide database. The genotypic and phenotypic analyses allowed the differentiation of strain LMG 28769T from all recognized Bifidobacterium species. Strain LMG 28769T ( = CCUG 67145T = R 54638T) therefore represents a novel species, for which the name Bifidobacterium aquikefiri sp. nov. is proposed.