Nesterenkonia halotolerans sp. nov. and Nesterenkonia xinjiangensis sp. nov., actinobacteria from saline soils in the west of China

Genomic analysis of a halophilic bacterium Nesterenkonia sp. CL21 with ability to produce a diverse group of lignocellulolytic enzymes

Halophilic bacteria are extremophiles that thrive in saline environment. Their ability to withstand such harsh conditions makes them an ideal choice for industrial applications such as lignocellulosic biomass degradation. In this study, a halophilic bacterium with the ability to produce extracellular cellulases and hemicellulases, designated as Nesterenkonia sp. CL21, was isolated from mangrove sediment in Tanjung Piai National Park, Malaysia. Thus far, studies on lignocellulolytic enzymes concerning bacterial species under this genus are limited. To gain a comprehensive understanding of its lignocellulose-degrading potential, the whole genome was sequenced using the Illumina NovaSeq 6000 platform. The genome of strain CL21 was assembled into 25 contigs with 3,744,449 bp and a 69.74% GC content and was predicted to contain 3,348 coding genes. Based on taxonomy analysis, strain CL21 shares 73.8 to 82.0% average nucleotide identity with its neighbouring species, below the 95% threshold, indicating its possible status as a distinct species in Nesterenkonia genus. Through in-depth genomic mining, a total of 81 carbohydrate-active enzymes were encoded. Among these, 24 encoded genes were identified to encompass diverse cellulases (GH3), xylanases (GH10, GH11, GH43, GH51, GH127 and CE4), mannanases (GH38 and GH106) and pectinases (PL1, PL9, and PL11). The production of lignocellulolytic enzymes was tested in the presence of several substrates. This study revealed that strain CL21 can produce a diverse array of enzymes which are active at different time points. By combining experimental data with genomic information, the ability of strain CL21 to produce lignocellulolytic enzymes has been elucidated, with potential applications in biorefinery industry.

Description of Nesterenkonia aerolata sp. nov., an actinobacterium isolated from air of manufacturing shop in a pharmaceutical factory

During our studies on the microorganism diversity from air of manufacturing shop in a pharmaceutical factory in Shandong province, China, a Gram-stain-positive, aerobic, cocci-shaped bacterium, designated LY-0111T, was isolated from a settling dish. Strain LY-0111T grew at temperature of 10-42 °C (optimum 35 °C), pH of 5.0-10.0 (optimum pH 7.0) and NaCl concentration of 1-12% (optimum 0.5-3%, w/v). Based on the 16S rRNA gene sequence analysis, the strain shared the highest sequence similarities to Nesterenkonia halophila YIM 70179T (96.2%), and was placed within the radiation of Nesterenkonia species in the phylogenetic trees. The genome of the isolate was sequenced, which comprised 2,931,270 bp with G + C content of 66.5%. A supermatrix tree based on the gene set bac120 indicated that LY-0111T was close related to Nesterenkonia xinjiangensis YIM 70097T (16S rRNA gene sequence similarity 95.3%). Chemotaxonomic analysis indicated that the main respiratory quinones were MK-7, MK-8, and MK-9, the predominant cellular fatty acids were anteiso-C15:0 and iso-C15:0, and the major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. According to the phenotypic, chemotaxonomic and phylogenetic features, strain LY-0111T is considered to represent a novel species, for which the name Nesterenkonia aerolata sp. nov. is proposed. The type strain is LY-0111T (= JCM 36375T = GDMCC 1.3945T). In addition, Nesterenkonia jeotgali was proposed as a later synonym of Nesterenkonia sandarakina, according to the ANI (96.8%) and dDDH (72.9%) analysis between them.

Comparative Genomic Analyses of the Genus Nesterenkonia Unravels the Genomic Adaptation to Polar Extreme Environments

The members of the Nesterenkonia genus have been isolated from various habitats, like saline soil, salt lake, sponge-associated and the human gut, some of which are even located in polar areas. To identify their stress resistance mechanisms and draw a genomic profile across this genus, we isolated four Nesterenkonia strains from the lakes in the Tibetan Plateau, referred to as the third pole, and compared them with all other 30 high-quality Nesterenkonia genomes that are deposited in NCBI. The Heaps’ law model estimated that the pan-genome of this genus is open and the number of core, shell, cloud, and singleton genes were 993 (6.61%), 2782 (18.52%), 4117 (27.40%), and 7132 (47.47%), respectively. Phylogenomic and ANI/AAI analysis indicated that all genomes can be divided into three main clades, named NES-1, NES-2, and NES-3. The strains isolated from lakes in the Tibetan Plateau were clustered with four strains from different sources in the Antarctic and formed a subclade within NES-2, described as NES-AT. Genome features of this subclade, including GC (guanine + cytosine) content, tRNA number, carbon/nitrogen atoms per residue side chain (C/N-ARSC), and amino acid composition, in NES-AT individuals were significantly different from other strains, indicating genomic adaptation to cold, nutrient-limited, osmotic, and ultraviolet conditions in polar areas. Functional analysis revealed the enrichment of specific genes involved in bacteriorhodopsin synthesis, biofilm formation, and more diverse nutrient substance metabolism genes in the NES-AT clade, suggesting potential adaptation strategies for energy metabolism in polar environments. This study provides a comprehensive profile of the genomic features of the Nesterenkonia genus and reveals the possible mechanism for the survival of Nesterenkonia isolates in polar areas.

In-Depth Investigation of the Safety of Wooden Shelves Used for Traditional Cheese Ripening

The main goal of this research was to characterize the bacterial diversity of the wooden boards used for aging traditional Sicilian cheeses and to evaluate whether pathogenic bacteria are associated with these surfaces. Eighteen cheese dairy factories producing three traditional cheese typologies (PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano) were selected within the region of Sicily. The wooden shelf surfaces were sampled by a destructive method to detach wood splinters as well as by a nondestructive brushing to collect microbial cells. Scanning electron microscopy showed the presence of almost continuous bacterial formations on the majority of the shelves analyzed. Yeasts and fungal hyphae were also visualized, indicating the complexity of the plank communities. The amplicon library of the 16S rRNA gene V3-V4 region was paired-end sequenced using the Illumina MiSeq system, allowing the identification of 14 phyla, 32 classes, 52 orders, 93 families, and 137 genera. Staphylococcus equorum was identified from all wooden surfaces, with a maximum abundance of 64.75%. Among cheese-surface-ripening bacteria, Brevibacterium and Corynebacterium were detected in almost all samples. Several halophilic (Halomonas, Tetragenococcus halophilus, Chromohalobacter, Salimicrobium, Marinococcus, Salegentibacter, Haererehalobacter, Marinobacter, and Idiomarinaceae) and moderately halophilic (Salinicoccus, Psychrobacter, and Salinisphaera) bacteria were frequently identified. Lactic acid bacteria (LAB) were present at low percentages in the genera Leuconostoc, Lactococcus, Lactobacillus, Pediococcus, and Streptococcus. The levels of viable microorganisms on the wooden shelves ranged between 2.4 and 7.8 log CFU/cm2. In some cases, LAB were counted at very high levels (8.2 log CFU/cm2). Members of the Enterobacteriaceae family were detected in a viable state for only six samples. Coagulase-positive staphylococci, Salmonella spp., and Listeria monocytogenes were not detected. Seventy-five strains belonged to the genera Leuconostoc, Lactococcus, Pediococcus, Enterococcus, Lactobacillus, and Weissella. IMPORTANCE This study provides evidence for the lack of pathogenic bacteria on the wooden shelves used to ripen internal bacterially ripened semihard and hard cheeses produced in Sicily. These three cheeses are not inoculated on their surfaces, and surface ripening is not considered to occur or, at least, does not occur at the same extent as surface-inoculated smear cheeses. Several bacterial groups identified from the wooden shelves are typically associated with smear cheeses, strongly suggesting that PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano cheese rind contributes to their final organoleptic profiles.

Nesterenkonia ebinurensis sp. nov., a Novel Actinobacterium Isolated From Populus euphratica

During our studies focused on the microorganism diversity and community structure of Populus euphratica at Ebinur lake wetland nature reserve in Xinjiang Uyghur Autonomous Region, PR China, a Gram-positive, aerobic, short rod-shaped bacterium without flagellum, designated as MD2^T, was isolated from a piece of resina on Populus euphratica. The isolate grew at temperature of 10-45 °C (optimum 37 °C), pH of 7.0-12.0 (optimum pH 8.0) and NaCl concentration of 1-18% (optimum 3%, w/v). Based on the 16S rRNA gene sequences and the phylogenetic analysis, the strain shared the highest sequence similarities to Nesterenkonia alkaliphila JCM 19766^T (96.3%), Nesterenkonia populi KCTC 29119^T (95.9%), Nesterenkonia alba CCTCC AB 207011^T (95.5%), and was placed within the radiation of Nesterenkonia species in the phylogenetic trees. The draft genome of the isolate was sequenced, which comprised 3,739,891 bp with G + C content of 63 mol%, and was annotated to contain 3614 protein-coding genes, 44 tRNA genes and 5 rRNA genes. Chemotaxonomic analysis indicated that the main respiratory quinones were MK-8 and MK-9, the predominant cellular fatty acids were anteiso-C_17:0, anteiso-C_15:0 and iso-C_16:0, the major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol andphosphatidylinositol. According to the phenotypic, chemotaxonomic and phylogenetic features, strain MD2^T is considered to represent a novel species, for which the name Nesterenkonia ebinurensis sp. nov. is proposed. The type strain is MD2^T (= KCTC 52999^T = MCCC 1K03343^T).

From ecophysiology to cultivation methodology: filling the knowledge gap between uncultured and cultured microbes

Earth is dominated by a myriad of microbial communities, but the majority fails to grow under in situ laboratory conditions. The basic cause of unculturability is that bacteria dominantly occur as biofilms in natural environments. Earlier improvements in the culture techniques are mostly done by optimizing media components. However, with technological advancement particularly in the field of genome sequencing and cell imagining techniques, new tools have become available to understand the ecophysiology of microbial communities. Hence, it becomes easier to mimic environmental conditions in the culture plate. Other methods include co-culturing, emendation of growth factors, and cultivation after physical cell sorting. Most recently, techniques have been proposed for bacterial cultivation by employing genomic data to understand either microbial interactions (network-directed targeted bacterial isolation) or ecosystem engineering (reverse genomics). Hopefully, these techniques may be applied to almost all environmental samples, and help fill the gaps between the cultured and uncultured microbial communities.

Nesterenkonia pannonica sp. nov., a novel alkaliphilic and moderately halophilic actinobacterium

An alkaliphilic and moderately halophilic bacterial strain characterized by optimal growth at pH 9.0-10.0 and with 5-7 % (w/v) NaCl, designated BV-35^T, was isolated from water of a soda pan located in Kiskunság National Park, Hungary. Cells of the orange-pigmented colony were Gram-stain-positive, non-motile and non-endospore-forming coccoid rods. The isolate was strictly aerobic, catalase-positive and oxidase-negative. Strain BV-35^T displayed a peptidoglycan similar to type A4α, l-Lys-l-Glu (A11.54 according to www.peptidoglycan-types.info) but containing additionally 4-aminobutyric acid. Menaquinone-7 (MK-7) was the predominant isoprenoid quinone, and anteiso-C15 : 0 and anteiso-C17 : 0 were its major cellular fatty acids. The DNA G+C content of strain BV-35^T was 65.4 mol%. Based on 16S rRNA gene sequence similarities, the novel isolate showed the closest relationship to Nesterenkonia populi GP 10-3^T (97.9 %). The DNA-DNA relatedness between BV-35^T and N. populi was 46.7 %. The distinguishing phenotypic and genetic results of this polyphasic study revealed that strain BV-35^T represents a novel member of the genus Nesterenkonia, for which the name Nesterenkonia pannonica sp. nov. is proposed. The type strain is BV-35^T (=DSM 29786^T=NCAIM B 02606^T).

Nesterenkonia cremea sp. nov., a bacterium isolated from a soda lake

A Gram-stain-positive, aerobic, non-motile, rod-shaped, non-endospore-forming bacterial strain, 10CT, was isolated from Lonar soda lake in India. Based on the 16S rRNA gene sequence analysis, this strain was identified as belonging to the genus Nesterenkonia and was most closely related to the type strains of Nesterenkonia lacusekhoensis (99.1 %, sequence similarity), Nesterenkonia aethiopica (96.9 %), Nesterenkonia flava (96.9 %) and related of the genus Nesterenkonia (<96.6 %, sequence similarity). However, the DNA-DNA relatedness of strain 10CT with N. lacusekhoensis KCTC 19283T was only 34.6±0.9. The DNA G+C content of strain 10CT was 68.6 mol%. Strain 10CT was an aerobic microbe with optimal growth at 37 °C, pH 7.5-8.0 and 5-6 % (w/v) NaCl. The cell-wall peptidoglycan of strain 10CT was of the type A4α (l-Lys-l-Glu). The major polar lipids present were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. The major isoprenoid quinones were MK-7, MK-8 and MK-9. Major fatty acids of strain 10CT were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The results of phylogenetic, chemotaxonomic and biochemical tests allowed a clear differentiation of strain 10CT, which represents a novel member of the genus Nesterenkonia for which the name Nesterenkonia cremea sp. nov. is proposed. The type strain is 10CT (=LMG 29100T=KCTC 39636T=CGMCC 1.15388T).

Genome Insight and Comparative Pathogenomic Analysis of Nesterenkonia jeotgali Strain CD08_7 Isolated from Duodenal Mucosa of Celiac Disease Patient

Species of the genus Nesterenkonia have been isolated from different ecological niches, especially from saline habitats and reported as weak human pathogens causing asymptomatic bacteraemia. Here, for the first time we are reporting the genome sequence and pathogenomic analysis of a strain designated as CD08_7 isolated from the duodenal mucosa of a celiac disease patient, identified as Nesterenkonia jeotgali. To date, only five strains of the genus Nesterenkonia (N. massiliensis strain NP1^T, Nesterenkonia sp. strain JCM 19054, Nesterenkonia sp. strain F and Nesterenkonia sp. strain AN1) have been whole genome sequenced and annotated. In the present study we have mapped and compared the virulence profile of N. jeotgali strain CD08_7 along with other reference genomes which showed some characteristic features that could contribute to pathogenicity. The RAST (Rapid Annotation using Subsystem Technology) based genome mining revealed more genes responsible for pathogenicity in strain CD08_7 when compared with the other four sequenced strains. The studied categories were resistance to antibiotic and toxic compounds, invasion and intracellular resistance, membrane transport, stress response, osmotic stress, oxidative stress, phages and prophages and iron acquisition. A total of 1431 protein-encoding genes were identified in the genome of strain CD08_7 among which 163 were predicted to contribute for pathogenicity. Out of 163 genes only 59 were common to other genome, which shows the higher levels of genetic richness in strain CD08_7 that may contribute to its functional versatility. This study provides a comprehensive analysis on genome of N. jeotgali strain CD08_7 and possibly indicates its importance as a clinical pathogen.

Nesterenkonia aurantiaca sp. nov., an alkaliphilic actinobacterium isolated from Antarctica

A Gram-stain-positive, non-endospore-forming, haloalkaliphilic actinobacterium, strain CK5^T, was isolated from a soil sample, collected at Cape King (Antarctica), and its taxonomic position was investigated by using a polyphasic approach. Cells were cocci with orange pigmentation, non-motile and grew optimally at 25 °C and pH 9.0-9.5 in the presence of 2 % (w/v) NaCl. Cellular membrane contained MK-7 (72 %) and MK-8 (28 %), and anteiso-C_15 : 0 (64.8 %), iso-C_16 : 0 (13.3 %), n-C_17 : 0 (9.9 %), n-C_16 : 0 (4.0 %), n-C_14 : 0 (3.7 %) as major cellular fatty acids. The DNA G+C content was 64.8 mol%. Strain CK5^T, based on the 16S rRNA gene sequence similarity, was most closely related to Nesterenkonia jeotgali JG-241^T (99.5 %), Nesterenkonia sandarakina YIM 70009^T (99.4 %), Nesterenkonia lutea YIM 70081^T (99.4 %), Nesterenkonia halotolerans YIM 70084^T (99.3 %), Nesterenkonia xinjiangensis YIM 70097^T (97.2 %), Nesterenkonia flava CAAS 251^T (97.1 %) and Nesterekonia aethiopica CCUG 48939^T (97.1 %). Strain CK5^T revealed 31 % DNA-DNA relatedness with respect to N. sandarakina DSM 15664^T, 29 % with respect to N. jeotgali DSM 19081^T, 10 % with respect to N. lutea DSM 15666^T and 1 % with respect to N. halotolerans, DSM 15474^T, N. xinjiangensis DSM 15475^T, N. aethiopica DSM 17733^T and N. flava DSM 19422^T. On the basis of 16S rRNA gene sequences, DNA-DNA hybridization and chemotaxonomic characteristics, strain CK5^T represents a novel species of the genus Nesterenkonia, for which the name Nesterenkonia aurantiaca sp. nov. is proposed. The type strain is CK5^T ( = DSM 27373^T = JCM 19723^T).

Review of the taxonomy of the genus Arthrobacter, emendation of the genus Arthrobacter sensu lato, proposal to reclassify selected species of the genus Arthrobacter in the novel genera Glutamicibacter gen. nov., Paeniglutamicibacter gen. nov., Pseudoglutamicibacter gen. nov., Paenarthrobacter gen. nov. and Pseudarthrobacter gen. nov., and emended description of Arthrobacter roseus

In this paper, the taxonomy of the genus Arthrobacter is discussed, from its first description in 1947 to the present state. Emphasis is given to intrageneric phylogeny and chemotaxonomic characteristics, concentrating on quinone systems, peptidoglycan compositions and polar lipid profiles. Internal groups within the genus Arthrobacter indicated from homogeneous chemotaxonomic traits and corresponding to phylogenetic grouping and/or high 16S rRNA gene sequence similarities are highlighted. Furthermore, polar lipid profiles and quinone systems of selected species are shown, filling some gaps concerning these chemotaxonomic traits. Based on phylogenetic groupings, 16S rRNA gene sequence similarities and homogeneity in peptidoglycan types, quinone systems and polar lipid profiles, a description of the genus Arthrobacter sensu lato and an emended description of Arthrobacter roseus are provided. Furthermore, reclassifications of selected species of the genus Arthrobacter into novel genera are proposed, namely Glutamicibacter gen. nov. (nine species), Paeniglutamicibacter gen. nov. (six species), Pseudoglutamicibacter gen. nov. (two species), Paenarthrobacter gen. nov. (six species) and Pseudarthrobacter gen. nov. (ten species).

Garicola koreensis gen. nov., sp. nov., isolated from saeu-jeot, traditional Korean fermented shrimp

A novel Gram-staining-positive, non-endospore-forming, aerobic bacterium, designated strain SJ5-4T, was isolated from seau-jeot, a traditional food that is made by fermentation of highly salted [approximately 25 % (w/v)] shrimp in Korea. Cells were moderately halophilic, non-motile cocci or short rods that showed catalase- and oxidase-positive reactions. Growth of strain SJ5-4T was observed at 15–40 °C (optimum, 30 °C), at pH 6.0–9.5 (optimum, pH 6.5–7.0) and in the presence of 1–17 % (w/v) NaCl (optimum, 6 %). The major cellular fatty acids of strain SJ5-4T were anteiso-C15 : 0, iso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and C16 : 0. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, an unidentified phospholipid, three glycolipids and an unidentified lipid were detected as the polar lipids. Strain SJ5-4T belonged to the exceptionally small group of strains within the order Micrococcales that show a peptidoglycan cross-linked according to the A-type but containing 2,4-diaminobutyric acid. The G+C content of the genomic DNA was 61.8 mol%. MK-7, MK-8 and MK-9 were detected as the isoprenoid quinones. Strain SJ5-4T was most closely related to members of the genus Nesterenkonia, with 16S rRNA gene sequence similarities of 93.1–94.8 %. However, phylogenetic inference based on 16S rRNA gene sequences showed that strain SJ5-4T formed a phyletic lineage distinct from members of the genus Nesterenkonia within the family Micrococcaceae . On the basis of its phenotypic and molecular features, strain SJ5-4T represents a novel genus and species of the family Micrococcaceae , for which the name Garicola koreensis gen. nov., sp. nov. is proposed. The type strain of Garicola koreensis is SJ5-4T ( = KACC 16909T = JCM 18572T = DSM 28238T).

Nesterenkonia populi sp. nov., an actinobacterium isolated from Populus euphratica

An alkaliphilic and moderately halophilic actinobacterium, designated strain GP10-3(T), was isolated from Populus euphratica collected from the southern edge of Taklimakan desert, Xinjiang, China. Cells of this strain were Gram-stain-positive, non-motile and non-spore-forming short rods. Strain GP10-3(T) grew optimally at 37 °C on LB agar media in the presence of 5-10% (w/v) NaCl at pH 9.0. The menaquinones were MK-7, MK-8 and MK-9. The major fatty acids (>10%) were anteiso-C17 : 0, anteiso-C15 : 0 and iso-C16 : 0. The peptidoglycan type was variation A4α, L-Lys-L-Glu. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylglycolipid, phosphatidylcholine, phosphatidylinositol, glycolipid and an unidentified phospholipid. The DNA G+C content was 67.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain GP10-3(T) belonged to the genus Nesterenkonia , sharing 94.6-96.9% sequence similarity with the type strains of species within this genus with validly published names. Based on the evidence of the polyphasic taxonomic study, strain GP10-3(T) represents a novel species of the genus Nesterenkonia , for which the name Nesterenkonia populi sp. nov. is proposed. The type strain is GP10-3(T) ( = DSM 27959(T) = KCTC 29119(T)).

Nesterenkonia alkaliphila sp. nov., an alkaliphilic, halotolerant actinobacteria isolated from the western Pacific Ocean

A Gram-staining-positive, aerobic, motile and non-spore-forming actinobacteria, designated strain F10T, was isolated from a deep-sea sediment of the western Pacific Ocean. Phylogenetic and phenotypic properties of the organism supported that it belonged to the genus Nesterenkonia . Strain F10T shared highest 16S rRNA gene sequence similarity of 96.8 % with Nesterenkonia aethiopica DSM 17733T, followed by Nesterenkonia xinjiangensis YIM 70097T (96.7 %) and Nesterenkonia alba CAAS 252T (96.6 %). The organism grew at 4–50 °C, at pH 7.0–12.0 and in the presence of 0–12 % (w/v) NaCl, with optimal growth occurring at 40 °C, at pH 9.0 and in the presence of 1 % (w/v) NaCl. The peptidoglycan type was A4(alpha), l-Lys–Gly–l-Glu. The polar lipid profile of strain F10T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unknown glycolipids and two unknown lipids. The isolate contained MK-9 (92 %) and MK-8 (5.8 %) as the major components of the menaquinone system, and anteiso-C17 : 0 (50.9 %) and anteiso-C15 : 0 (29.8 %) as the predominant fatty acids. The G+C content of the genomic DNA of strain F10T was 66.2 mol%. Based on phenotypic, genotypic and phylogenetic analyses, strain F10T represents a novel species of the genus Nesterenkonia for which the name Nesterenkonia alkaliphila sp. nov. is proposed. The type strain is F10T ( = LMG 28112T = CGMCC 1.12781T = JCM 19766T = MCCC 1A09946T).

Nesterenkonia rhizosphaerae sp. nov., an alkaliphilic actinobacterium isolated from rhizosphere soil in a saline-alkaline desert

An alkaliphilic actinobacterial strain, designated EGI 80099(T), was isolated from a rhizosphere soil sample of Reaumuria soongorica found in the desert soils of Fukang, Xinjiang, north-west China. Cells of strain EGI 80099(T) were Gram-stain-positive, non-motile, non-endospore-forming cocci. The predominant menaquinones were MK-7, MK-8 and MK-9. The major cellular fatty acids (>10 %) were anteiso-C15 : 0 and anteiso-C17 : 0. Analysis of the cell wall showed the presence of peptidoglycan of the type l-Lys-Gly-l-Glu, variation A4α. Cells of the isolate contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unknown phospholipid and an unidentified glycolipid as polar lipids. The genomic DNA G+C content was 63.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain EGI 80099(T) belongs to the genus Nesterenkonia, sharing 95.68-97.37 % sequence similarities with the type strains of recognized species within this genus. DNA-DNA hybridization of strain EGI 80099(T) with the type strains of species that showed the highest sequence similarities, Nesterenkonia aethiopica DSM 17733(T) (97.37 %), Nesterenkonia flava CAAS 251(T) (97.23 %) and Nesterenkonia xinjiangensis YIM 70097(T) (97.02 %), gave relatedness values of 8.7-62.2 %. Data from DNA-DNA hybridizations and physiological and biochemical tests indicated that strain EGI 80099(T) represents a novel species of the genus Nesterenkonia, for which the name Nesterenkonia rhizosphaerae sp. nov. is proposed. The type strain is EGI 80099(T) ( = BCRC 16947(T) = JCM 19129(T)).

Halophilic microorganisms are responsible for the rosy discolouration of saline environments in three historical buildings with mural paintings

A number of mural paintings and building materials from monuments located in central and south Europe are characterized by the presence of an intriguing rosy discolouration phenomenon. Although some similarities were observed among the bacterial and archaeal microbiota detected in these monuments, their origin and nature is still unknown. In order to get a complete overview of this biodeterioration process, we investigated the microbial communities in saline environments causing the rosy discolouration of mural paintings in three Austrian historical buildings using a combination of culture-dependent and -independent techniques as well as microscopic techniques. The bacterial communities were dominated by halophilic members of Actinobacteria, mainly of the genus Rubrobacter. Representatives of the Archaea were also detected with the predominating genera Halobacterium, Halococcus and Halalkalicoccus. Furthermore, halophilic bacterial strains, mainly of the phylum Firmicutes, could be retrieved from two monuments using special culture media. Inoculation of building materials (limestone and gypsum plaster) with selected isolates reproduced the unaesthetic rosy effect and biodeterioration in the laboratory.

Genome sequence and description of Nesterenkonia massiliensis sp. nov. strain NP1(T.)

Nesterenkonia massiliensis sp. nov., strain NP1^T, is the type strain of Nesterenkonia massiliensis sp. nov., a new species within the genus Nesterenkonia. This strain, whose genome is described here, was isolated from the feces of a 32-year-old French woman suffering from AIDS and living in Marseille. Nesterenkonia massiliensis is a Gram-positive aerobic coccus. Here, we describe the features of this bacterium, together with the complete genome sequencing and annotation. The 2,726,371 bp long genome (one chromosome but no plasmid) contains 2,663 protein-coding and 51 RNA genes, including 1 rRNA operon.

Nesterenkonia suensis sp. nov., a haloalkaliphilic actinobacterium isolated from a salt pan

A Gram-positive, non-motile, non-spore-forming actinobacterium designated strain Sua-BAC020T was isolated from brine from Sua salt pan in Botswana. The strain was alkaliphilic and moderately halophilic, displaying optimal growth at 35–37 °C, pH 9 and 2.5 % (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain Sua-BAC020T belonged to the genus Nesterenkonia , sharing 96.2–99.0 % sequence similarity with the type strains of recognized species within this genus. DNA–DNA hybridization with the type strains of species that showed the closest phylogenetic affiliation, Nesterenkonia xinjiangensis (16S rRNA gene sequence similarity, 98.9 %), Nesterenkonia aethiopica (99.0 %), Nesterenkonia halophila (97.5 %), Nesterenkonia flava (97.4 %) and Nesterenkonia halobia (97.2 %), gave relatedness values of 10–45 %. The peptidoglycan type of strain Sua-BAC020T was A4α, l-Lys–Gly–d-Asp. Cells of the isolate contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and unidentified glycolipids as major polar lipids, MK-8, MK-9 and MK-7 were the predominant menaquinones, and the major fatty acids (>10 %) were anteiso-C15 : 0 and anteiso-C17 : 0. The DNA G+C content of strain Sua-BAC020T was 64.8 mol%. Based on DNA–DNA hybridization, and physiological and biochemical tests, strain Sua-BAC020T is distinct from all recognized Nesterenkonia species, suggesting that this strain represents a novel species, for which the name Nesterenkonia suensis sp. nov. is proposed. The type strain is Sua-BAC020T ( = DSM 22748T = NCCB 100309T).

Systematic and biotechnological aspects of halophilic and halotolerant actinomycetes

More than 70 species of halotolerant and halophilic actinomycetes belonging to at least 24 genera have been validly described. Halophilic actinomycetes are a less explored source of actinomycetes for discovery of novel bioactive secondary metabolites. Degradation of aliphatic and aromatic organic compounds, detoxification of pollutants, production of new enzymes and other metabolites such as antibiotics, compatible solutes and polymers are other potential industrial applications of halophilic and halotolerant actinomycetes. Especially new bioactive secondary metabolites that are derived from only a small fraction of the investigated halophilic actinomycetes, mainly from marine habitats, have revealed the huge capacity of this physiological group in production of new bioactive chemical entities. Combined high metabolic capacities of actinomycetes and unique features related to extremophilic nature of the halophilic actinomycetes have conferred on them an influential role for future biotechnological applications.

Unique aliphatic amidase from a psychrotrophic and haloalkaliphilic nesterenkonia isolate

Nesterenkonia strain AN1 was isolated from a screening program for nitrile- and amide-hydrolyzing microorganisms in Antarctic desert soil samples. Strain AN1 showed significant 16S rRNA sequence identity to known members of the genus. Like known Nesterenkonia species, strain AN1 was obligately alkaliphilic (optimum environmental pH, 9 to 10) and halotolerant (optimum environmental Na(+) content, 0 to 15% [wt/vol]) but was also shown to be an obligate psychrophile with optimum growth at approximately 21°C. The partially sequenced genome of AN1 revealed an open reading frame (ORF) encoding a putative protein member of the nitrilase superfamily, referred to as NitN (264 amino acids). The protein crystallized readily as a dimer and the atomic structure of all but 10 amino acids of the protein was determined, confirming that the enzyme had an active site and a fold characteristic of the nitrilase superfamily. The protein was screened for activity against a variety of nitrile, carbamoyl, and amide substrates and was found to have only amidase activity. It had highest affinity for propionamide but demonstrated a low catalytic rate. NitN had maximal activity at 30°C and between pH 6.5 and 7.5, conditions which are outside the optimum growth range for the organism.

Zhihengliuella halotolerans gen. nov., sp. nov., a novel member of the family Micrococcaceae

The actinobacterial strain YIM 70185T was isolated from a saline soil sample collected from Qinghai province, north-west China, and subjected to a taxonomic investigation. Phylogenetic analysis based on 16S rRNA gene sequences revealed 93.5–96.4 % similarity to members of related genera in the family Micrococcaceae. In the phylogenetic dendrogram based on 16S rRNA gene sequence analysis, strain YIM 70185T formed a separate clade next to the genera Micrococcus and Citricoccus within the family Micrococcaceae. The peptidoglycan type was A4α, l-lys–l-ala–l-Glu. Cell-wall sugars contained glucose and tyvelose. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, an unknown phospholipid and an unknown glycolipid. The menaquinones were MK-9, MK-10 and MK-8 (molar ratio 5 : 2 : 1). The major fatty acids were ai-C15 : 0 and i-C15 : 0 and the DNA G+C content was 66.5 mol%. These chemotaxonomic profiles supported the assignment of strain YIM 70185T to a novel genus within the family Micrococcaceae. The name Zhihengliuella halotolerans gen. nov., sp. nov. is proposed. The type strain of Zhihengliuella halotolerans is YIM 70185T (=DSM 17364T=KCTC 19085T).

Nesterenkonia jeotgali sp. nov., isolated from jeotgal, a traditional Korean fermented seafood

A Gram-positive, non-motile, slightly halophilic actinomycete, strain JG-241T, was isolated from jeotgal, a traditional Korean fermented seafood, and its taxonomic position was investigated by using a polyphasic approach. Strain JG-241T grew optimally at 25–30 °C and in the presence of 2–5 % (w/v) NaCl. The physiological and biochemical properties of strain JG-241T were distinguishable from those of recognized Nesterenkonia species. Strain JG-241T had a peptidoglycan type based on l-lys–gly–d-Asp. It contained MK-7, MK-8 and MK-9 as the predominant menaquinones and anteiso-C15 : 0 and anteiso-C17 : 0 as the major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unidentified glycolipid. The DNA G+C content was 68.0 mol%. Comparative 16S rRNA gene sequence analysis showed that strain JG-241T falls within the radiation of the cluster comprising Nesterenkonia species. Similarity values between the 16S rRNA gene sequence of strain JG-241T and those of the type strains of Nesterenkonia species ranged from 96.7 to 99.7 %. DNA–DNA relatedness data and repetitive extragenic palindromic DNA-PCR genomic fingerprinting patterns showed that strain JG-241T differs genetically from recognized Nesterenkonia species. On the basis of its phenotypic properties and phylogenetic and genetic distinctiveness, strain JG-241T represents a novel species of the genus Nesterenkonia, for which the name Nesterenkonia jeotgali sp. nov. is proposed. The type strain is JG-241T (=KCTC 19053T=JCM 12610T).

Nesterenkonia aethiopica sp. nov., an alkaliphilic, moderate halophile isolated from an Ethiopian soda lake

Strain DSM 17733(T), isolated from the shore of Lake Abjata in Ethiopia, is a heterotrophic, alkaliphilic, moderately halophilic, Gram-positive, strictly aerobic, non-motile,non-endospore-forming bacterium. The organism grows optimally at 30-37 degrees C, pH 9 and 3 % (w/v) NaCl. Analysis of the cell wall showed the presence of murein of the type L-lys-gly-L-Glu, variation A4alpha. The G + C content of the genomic DNA was 69.0 mol%. Sequence analysis of 16S rRNA gene sequence of strain DSM 17733(T) placed the isolate in the genus Nesterenkonia. DNA-DNA hybridization of DSM 17733(T) with those organisms with the closest phylogenetic affiliation, i.e. Nesterenkonia halobia, Nesterenkonia lacusekhoensis and Nesterenkonia xinjiangensis, gave relatedness values of 48.5 %, 63.7 % (repetition, 57.2 %) and 35.7 % (repetition, 29.3 %), respectively. On the basis of both phenotypic and phylogenetic criteria and the low levels of DNA-DNA relatedness with the phylogenetically closest species N. xinjiangensis and N. halobia, it is proposed that the isolate be classified in a novel species, Nesterenkonia aethiopica sp. nov. The type strain is DSM 17733(T) (=CCUG 48939(T)).

Sinococcus qinghaiensis gen. nov., sp. nov., a novel member of the order Bacillales from a saline soil in China

A Gram-positive, non-spore-forming isolate, designated YIM 70212T, was isolated from a hypersaline soil sample collected from Qinghai, north-west China. Cells of the isolate were orange-pigmented, motile cocci with multiple flagella. A polyphasic taxonomic investigation was carried out on the isolate. The organism grew at 10–45 °C and pH 7.5–11.0, with optimum growth at 28 °C and pH 8.0–9.5. Strain YIM 70212T grew optimally in the presence of 10 % NaCl, KCl or MgCl2.6H2O and growth was observed in 1–25 % NaCl, KCl or MgCl2.6H2O. The peptidoglycan type was A1γ. Ribose and minor amounts of galactose were detected as the whole-cell sugars. MK-5 was the only menaquinone. The major cellular fatty acids were ai-C15 : 0 (52.4 %) and ai-C17 : 0 (26.5 %). The DNA G+C content was 47.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM 70212T formed a distinct lineage within the order Bacillales and was most closely related to members of the genus Marinococcus, showing 16S rRNA gene sequence similarity levels of 91.0–91.4 %. Based on the high 16S rRNA gene sequence divergence and differences in phenotypic characteristics, it is proposed that the unknown strain be classified in a novel genus and species with the name Sinococcus qinghaiensis gen. nov., sp. nov.; the type strain of Sinococcus qinghaiensis is YIM 70212T (=KCTC 3943T=DSM 17008T).

Identification of sulfoquinovosyl diacylglycerol as a major polar lipid in Marinococcus halophilus and Salinicoccus hispanicus and substitution with phosphatidylglycerol

The sulfonolipid sulfoquinovosyl diacylglycerol normally associated with photosynthetic membranes was identified as a major lipid in Marinococcus halophilus, Salinicoccus hispanicus ("Marinococcus hispanicus"), and Marinococcus sp. H8 (Planococcus sp. H8). Phosphatidylglycerol and 0%–10% cardiolipin accounted for the remaining polar lipids in these moderately halophilic, Gram-positive bacteria. Negative-ion fast atom bombardment mass spectrometry was used to quantify these three polar lipids from cells grown in media containing 0.03 to 4 mol NaCl/L. All strains revealed dramatic shifts in the ratio of sulfonolipid to phospholipid dependent on the salinity of the growth media, when grown in media with low phosphate content. Highest sulfonolipid content occurred during best growth in 0.5–2 mol NaCl/L, approaching 80%–90% of the total polar lipids. It was demonstrated that growth of M. halophilus in the presence of elevated phosphate and low sulfate blocked the shift to decreased phospholipids most notably during growth in 0.5–2 mol NaCl/L, without significant influence on growth. The data suggest that in low-phosphate media the influence of NaCl concentration on growth rate (and resulting demand for phosphate by competing pathways) is the primary factor responsible for exchange between phospholipid and sulfonolipid. We conclude that sulfoquinovosyl diacylglycerol, by substitution with phospholipids, contributes to the ability of these Gram-positive cocci to adapt to changing ionic environments. A comparison of 16S rRNA established a close similarity between Planococcus sp. H8 and M. halophilus.Key words: sulfoquinovosyl diacylglycerol, salinity, Marinococcus halophilus, Salinicoccus hispanicus, Marinococcus sp. H8 (Planococcus sp. H8).

Ecophysiology and molecular phylogeny of bacteria isolated from alkaline two-phase olive mill wastes

The use of two-phase centrifugal decanters has been widely adopted in the olive oil extraction industry in order to reduce the huge quantities of wastewaters produced during the traditional three-phase extraction process. The resulting sludge-like byproduct, widely known as "alpeorujo", has a pH of 4-6, low water activity (a(w)) and high phytotoxicity. Addition of Ca(OH)(2) to alpeorujo, which is commonly performed at the olive oil mill to handle disposal problems related to acidic pH and odor emissions, creates an alkaline secondary waste (alkaline alpeorujo). Bacteria isolated from alkaline alpeorujo were cultured in order to investigate their physiological and phylogenetic characteristics. The bacterial population at neutral pH was estimated to be 6.0+/-0.4 x 10(7) cells g(-1) dw, while the bacterial population at pH 11 reached 2.1+/-0.3 x 10(5) cells g(-1) dw. Fourteen strains isolated from alkaline pH were halotolerant alkaliphiles, while seven isolates from neutral pH were moderate to extreme halotolerant or/and alkalitolerant bacteria. Based on 16S rRNA gene sequence analysis, four of the halotolerant alkaliphilic isolates showed 98.4-99.2% similarity to known sequences of Bacillus alcalophilus and Nesterenkonia lacusekhoensis, whereas ten isolates demonstrated low percentage similarities (94.4-96.9%) to the genera Idiomarina, Halomonas and Nesterenkonia. As concerns bacteria isolated from neutral pH, four isolates were associated with Corynebacterium, Novosphingobium, Serratia marcescens and Pseudomonas aeruginosa (98.3-99.9% similarities), while three isolates presented 96.5-97.2% sequence similarities to Rhodobacter, Pseudomonas and Ochrobactrum. At least six groups of isolates represent novel phylogenetic linkages among Bacteria.

Bacillus nematocida sp. nov., a novel bacterial strain with nematotoxic activity isolated from soil in Yunnan, China

An endospore-forming bacterium, designated strain B-16T, was isolated from a forest soil sample in Yunnan, China. The isolate presented remarkable nematotoxic activity against nematode Panagrellus redivivus. The organism was strictly aerobic, motile, spore forming and rod shaped, catalase- and oxidase-positive. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major cellular fatty acid profiles were anteiso-C15:0 (48.67%), iso-C15:0 (13.45%), C16:0 (9.06%) and anteiso-Cl7:0 (8.29%). The DNA G+C content was 46%. Phylogenetic analyses based on 16S rDNA sequence revealed that isolate belongs to the genus Bacillus. Strain B-16T exhibited high 16S rDNA similarity with its closest neighbors Bacillus vallismortis (99.79%), B. subtilis (99.43%), B. atrophaeus (99.43%), B. amyloliquefaciens (99.36%), B. licheniformis (98.0%) and less than 97.0% with all the other relative type strains in the genus Bacillus. The phenotypic and genotypic characteristics and DNA-DNA relatedness data indicate that strain B-16T should be distinguished from all the relative species of genus Bacillus. Therefore, on the basis of the polyphasic taxonomic data presented, a new species of the genus Bacillus, B. nematocida, with the type strain B-16T ( = CGMCC 1128T) is proposed. The GenBank accession number for the sequence reported in this paper is AY820954.

Proposal of Yaniaceae fam. nov. and Yania flava sp. nov. and emended description of the genus Yania

A coccoid actinobacterium strain (designated YIM 70178T) was isolated from a soil sample collected in Qinghai Province, China. The isolate grew well with an optimum salt concentration of 10–15 % (KCl, w/v) but scarcely or not at all without salt. The cell-wall peptidoglycan type was A4α, l-lys–gly–l-Glu. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unknown phospholipid and an unknown glycolipid. The predominant menaquinones were MK-8 and MK-9. The major fatty acid was anteiso-C15 : 0. The DNA G+C content was 57·9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 70178T was most closely related to the type strain of Yania halotolerans. DNA–DNA hybridization and comparison of physiological and chemotaxonomic characteristics demonstrated that strain YIM 70178T was different from Yania halotolerans. The name Yania flava sp. nov. is proposed, with strain YIM 70178T (=DSM 16377T=KCTC 19047T) as the type strain. Based on the phenotypic characteristics and phylogenetic position, as determined by 16S rRNA gene analysis and 16S rRNA signature nucleotide data, the genus description of Yania is therefore emended and strains YIM 70085T and YIM 70178T represent a novel family of the suborder Micrococcineae, for which the name Yaniaceae fam. nov. is proposed.

Marinococcus halotolerans sp. nov., isolated from Qinghai, north-west China

An aerobic bacterium was isolated from saline soil located in Qinghai, north-west China. The bacterium, designated YIM 70157T, was investigated using a polyphasic taxonomic approach. The Gram reaction of the organism was positive. Comparative 16S rRNA gene sequence analysis demonstrated the isolate to be a member of the genus Marinococcus, the closest phylogenetic neighbour of the unknown bacterium being Marinococcus halophilus DSM 20408T with a similarity of 99·4 %. The peptidoglycan type of YIM 70157T was A1γ, with meso-diaminopimelic acid as diagnostic diamino acid. The major fatty acids were ai-C15 : 0, ai-C17 : 0 and i-C16 : 0. The menaquinones were MK-7 and MK-6. The phospholipids were diphosphatidylglycerol and phosphatidylinositol. The G+C content of total DNA was 48·5 mol%. On the basis of phylogenetic and phenotypic evidence and DNA–DNA hybridization data, this isolate should be classified as a novel species of Marinococcus, for which the name Marinococcus halotolerans sp. nov. is proposed. The type strain is YIM 70157T (=DSM 16375T=KCTC 19045T).

Microbacterium halotolerans sp. nov., isolated from a saline soil in the west of China

A Gram-positive short rod isolated from a saline soil in China was characterized using a polyphasic approach. This actinobacterium grew over a wide salinity range [0–15 % NaCl, 0–20 % KCl and 0–30 % MgCl2.6H2O (w/v); optimum concentrations for growth were 5 % NaCl, 5–10 % KCl, 10 % MgCl2.6H2O]. The optimum growth temperature and pH were 28–30 °C and 7·0–8·0, respectively. Chemotaxonomic features (peptidoglycan-type B2β with glycolyl residues; major menaquinones MK-10 and MK-11; predominating iso- and anteiso-branched cellular fatty acids; DNA G+C content 66·5 mol%) placed this organism within the genus Microbacterium. 16S rRNA gene sequence analysis confirmed this classification of the strain, but showed that it was distinct from its nearest neighbours. It formed a separate branch with type strains of the genus Microbacterium, and also shared low sequence similarity with them (<96 %). Based on phenotypic and molecular taxonomic results, it is proposed that the unknown isolate should be classified as a novel species in the genus Microbacterium, for which the name Microbacterium halotolerans sp. nov. is proposed. The type strain is YIM 70130T (=KCTC 19017T=CIP 108071T).

Nesterenkonia sandarakina sp. nov. and Nesterenkonia lutea sp. nov., novel actinobacteria, and emended description of the genus Nesterenkonia

Two novel actinobacteria isolates, designated YIM 70009T and YIM 70081T, were characterized in order to determine their taxonomic position. Cells of strains YIM 70009T and YIM 70081T were cocci, although only the latter were motile. The G+C contents of their DNAs were 64·0 and 64·5 mol%, respectively. On the basis of chemotaxonomic characteristics and 16S rRNA gene sequence analysis, the two isolates were classified in the genus Nesterenkonia. DNA–DNA hybridization and comparison of phenotypic characteristics revealed that strains YIM 70009T and YIM 70081T differed from each other and from known species. Therefore, it is proposed that they represent two separate novel species of the genus Nesterenkonia: Nesterenkonia sandarakina sp. nov. (type strain, YIM 70009T=CCTCC AA 203007T=DSM 15664T=KCTC 19011T) and Nesterenkonia lutea sp. nov. (type strain, YIM 70081T=CCTCC AA 203010T=DSM 15666T=KCTC 19013T).