Isolation, Identification and Screening of Saharan Actinomycete Strain Streptomyces fimbriatus AC31 Endowed with Antimicrobial Activity.

The increasing global public health concern of antimicrobial resistance (AMR) necessitates exploration of natural antimicrobial agents as potential alternatives. This study aimed to investigate antimicrobial activities of Saharan actinomycetes, with specific focus on the strain Streptomyces fimbriatus AC31, that holds promising potential as an alternative to combat AMR. In this context, 32 actinomycetes were isolated from El Atteuf (Ghardaïa), Algeria. Isolates obtained were characterized morphologically and biochemically. Screened isolate was identified by 16S rRNA gene sequencing. Classification of actinomycete isolates was carried out by UPGMA (Unweighted Pair Group Method with Arithmetic Mean). Then, they were screened for their antimicrobial activity by cross-streak method. Identification of 32 isolates revealed 5 genera: Streptomyces (65.63%), Nocardia (9.38%), Streptosporangium (9.38%), Nocardiopsis (9.38%) and Actinomadura (6.25%). According to the biochemical and physiological characteristics, UPGMA classified the isolates in 4 phenons. A number of 24 (75.00%) isolates were active against Gram-positive bacteria, 21 (65.63%) isolates were effective against Gram-negative bacteria, and 25 (78.13%) isolates inhibited Candida albicans. Screened strain Streptomyces fimbriatus AC31 showed highest antagonistic activity and revealed an inhibition zones of 41, 38, 41, 42, and 44 mm, against B. subtilis (ATCC 6633), E. coli (ATCC 8739), S. typhimurium (ATCC 13331), S. aureus (ATCC 6538) and C. albicans (ATCC 10231), respectively. Phylogenetic identification of the AC 31 isolate using 16S rRNA gene sequence showed similarity of 100% with Streptomyces fimbriatus NBRC 15411T. Actinomycete isolates characterized in this study were endowed with antimicrobial activity against various pathogenic microorganisms that could be used efficiently in developing new antimicrobial substances.

Rare Halophilic Nocardiopsis from Algerian Saharan Soils as Tools for Biotechnological Processes in Pharmaceutical Industry.

The Sahara Desert, one of the most extreme ecosystems in the planet, constitutes an unexplored source of microorganisms such as mycelial bacteria. In this study, we investigated the diversity of halophilic actinobacteria in soils collected from five regions of the Algerian Sahara. A total of 23 halophilic actinobacterial strains were isolated by using a humic-vitamin agar medium supplemented with 10% NaCl. The isolated halophilic strains were subjected to taxonomic analysis using a polyphasic approach, which included morphological, chemotaxonomic, physiological (numerical taxonomy), and phylogenetic analyses. The isolates showed abundant growth in CMA (complex medium agar) and TSA (tryptic soy agar) media containing 10% NaCl, and chemotaxonomic characteristics were consistent with their assignment to the genus Nocardiopsis. Analysis of the 16S rRNA sequence of 23 isolates showed five distinct clusters and a similarity level ranging between 98.4% and 99.8% within the Nocardiopsis species. Comparison of their physiological characteristics with the nearest species showed significant differences with the closely related species. Halophilic Nocardiopsis isolated from Algerian Sahara soil represents a distinct phyletic line suggesting a potential new species. Furthermore, the isolated strains of halophilic Nocardiopsis were screened for their antagonistic properties against a broad spectrum of microorganisms by the conventional agar method (agar cylinders method) and found to have the capacity to produce bioactive secondary metabolites. Except one isolate (AH37), all isolated Nocardiopsis showed moderate to high biological activities against Pseudomonas syringae and Salmonella enterica, and some isolates showed activities against Agrobacterium tumefaciens, Serratia marcescens, and Klebsiella pneumoniae. However, no isolates were active against Bacillus subtilis, Aspergillus flavus, or Aspergillus niger. The obtained finding implies that the unexplored extreme environments such as the Sahara contain many new bacterial species as a novel drug source for medical and industrial applications.

Genome-based reclassification of Actinopolyspora righensis Meklat et al. 2013 as a later heterotypic synonym of Actinopolyspora lacussalsi Guan et al. 2013 and description of Actinopolyspora lacussalsi subsp. lacussalsi subsp. nov. and Actinopolyspora lacussalsi subsp. righensis subsp. nov.

A genome led phylophasic study was designed to determine the taxonomic status of a strain, DSM 45956, recovered from a Saharan desert soil. A wealth of taxonomic data, including average nucleotide identity and DNA:DNA hybridization (DDH) values, showed that the isolate and the type strains of Actinopolyspora lacussalsi and Actinopolyspora righensis belong to the same species. Consequently, it is proposed that A. righensis is a heterotypic synonym of A. lacussalsi. Similarly, DDH values and associated phenotypic data show that A. lacussalsi contains two subspecies, A. lacussalsi subsp. lacussalsi and A. lacussalsi subsp. righensis which includes isolate DSM 45956.

Biosorption of cationic and anionic dyes using the biomass of Aspergillus parasiticus CBS 100926T.

Aspergillus parasiticus (A. parasiticus) CBS 100926T was used as a biosorbent for the removal of Methylene Blue (MB), Congo Red (CR), Sudan Black (SB), Malachite Green Oxalate (MGO), Basic Fuchsin (BF) and Phenol Red (PR) from aqueous solutions. The batch biosorption studies were carried out as a function of dye concentration and contact time. The biosorption process followed the pseudo-first-order and the pseudo-second-order kinetic models and the Freundlich and Langmuir isotherm models. The resulting biosorbent was characterized by Scanning Electron Microscopy (SEM), X-Ray Diffractometer and Fourier Transformer Infrared Spectroscopy (FTIR) techniques. The results of the present investigation suggest that A. parasiticus can be used as an environmentally benign and low cost biomaterial for the removal of basic and acid dyes from aqueous solution.

Saccharothrix algeriensis NRRL B-24137, the first non-Streptomyces actinobacterium, produces holomycin after cystine feeding.

Saccharothrix algeriensis NRRL B-24137 is an actinobacterium isolated from Algerian Saharan soil. This strain has the ability to produce several dithiolopyrrolone antibiotic derivatives depending on the precursors added to the culture medium. This group of antibiotics is known for their potent antimicrobial and anticancer activities. Holomycin is a member of the dithiolopyrrolone group of antibiotics, and has already been isolated from several species of actinobacteria belonging to the genus Streptomyces and also from some Gram-negative bacteria. In this study, holomycin was produced for the first time in the culture broth of a non-Streptomyces actinobacteria. This antibiotic was induced by adding 5 mM of L-cystine as precursor to the semi-synthetic fermentation broth of Sa. algeriensis NRRL B-24137 and then fully identified after HPLC purification. The minimum inhibitory concentrations (MIC) of holomycin were determined against several pathogenic microorganisms, including Escherichia coli ATCC 10536 Klebsiella pneumoniae CIP 82.91, Listeria monocytogenes CIP 82110, Staphylococcus aureus CIP 7625, Aspergillus carbonarius M333, Fusarium culmorum FC1, Candida albicans IPA 200. This antibiotic showed a broad-spectrum antimicrobial activity, inhibiting a variety of Gram-positive and Gram-negative bacteria, and micro-fungi.

Antimicrobial activities of novel bipyridine compounds produced by a new strain of Saccharothrix isolated from Saharan soil.

The actinobacterium strain ABH26 closely related to Saccharothrix xinjiangensis, isolated from an Algerian Saharan soil sample, exhibited highly antagonist activity against Gram-positive bacteria, yeasts and filamentous fungi. Its ability to produce antimicrobial compounds was investigated using several solid culture media. The highest antimicrobial activity was obtained on Bennett medium. The antibiotics secreted by strain ABH26 on Bennett medium were extracted by methanol and purified by reverse-phase HPLC using a C18 column. The chemical structures of the compounds were determined after spectroscopic (1H NMR, 13C NMR, 1H-1H COSY and 1H-13C HMBC spectra), and spectrometric (mass spectrum) analyses. Two new cyanogriside antibiotics named cyanogriside I (1) and cyanogriside J (2), were characterized along with three known caerulomycins, caerulomycin A (3), caerulomycin F (4) and caerulomycinonitrile (5). This is the first report of cyanogrisides and caerulomycins production by a member of the Saccharothrix genus. The minimum inhibitory concentrations (MIC) of these antibiotics were determined against pathogenic microorganisms.

Mzabimycins A and B, novel intracellular angucycline antibiotics produced by Streptomyces sp. PAL114 in synthetic medium containing L-tryptophan.

In our previous studies, the production of four bioactive molecules by Streptomyces sp. PAL114 in complex ISP2 broth medium has been described. Three of these molecules belong to the angucycline family. In this study, two novel antibiotics belonging to the same family were produced by strain PAL114 on M2 synthetic medium containing L-tryptophan as precursor. These antibiotics, named mzabimycins A and B, were intracellular and produced only in the presence of L-tryptophan. After four days of culturing PAL114 in the M2 medium, the bioactive compounds were extracted from mycelium with methanol and then analyzed by HPLC on reverse phase C18 column. Two active purplish blue fractions were purified. The chemical structures of these molecules were determined on the basis of spectroscopic and spectrometric analyses (1H and 13C NMR, and mass spectra). They were identified to be novel angucycline derivative antibiotics. The pure molecules showed activity against some pathogenic Gram-positive bacteria which have multiple antibiotic resistance, such as Staphylococcus aureus MRSA 639c and Listeria monocytogenes ATCC 13932.

Reclassification of Mzabimyces algeriensis Saker et al. 2015 as Halopolyspora algeriensis comb. nov.

Halopolyspora alba AFM10251T was proposed to represent a novel species of a new genus belonging to the family Actinopolysporaceae in a previous study. The family Mzabimycetaceae , containing one genus, Mzabimyces, was proposed subsequently and Mzabimyces algeriensis H195T was the type strain. However, analysis of 16S rRNA gene sequence similarity showed that the two strains were highly similar (99.2 %). Phenotypic and chemotaxonomic data, as well as DNA-DNA hybridization confirmed that the two strains are different genomic species of the same genus, Halopolyspora. Mzabimyces algeriensis should be classified in the genus Halopolyspora as Halopolysporaalgeriensis comb. nov. The type strain of Halopolysporaalgeriensis is H195T (=DSM 46680T=CECT 8575T).

Planomonospora algeriensis sp. nov., an actinobacterium isolated from a Saharan soil of Algeria.

A filamentous actinobacterium, designated strain PM3T, was isolated from a Saharan soil sample collected from Béni-Abbès, Béchar (South-West Algeria). A polyphasic taxonomic study was carried out to establish the status of strain PM3T. The isolate was found to have morphological and chemotaxonomical properties associated with members of the genus Planomonospora. The new isolated microorganism developed cylindrical sporangia arranged in double parallel rows on aerial mycelium, each one containing a motile single sporangiospore. The cell wall of the strain was found to contain meso-diaminopimelic acid. Whole-cell hydrolysates were found to contain madurose, glucose, mannose and ribose. The predominant menaquinone was identified as MK-9(H2) (69.6%). The polar lipids detected were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, phosphatidylhydroxyethanolamine and glucosamine-containing lipids. The major fatty acids were found to be C17:1ω9c (38.6%) and C17:0 (24.2%). Results of 16S rRNA gene sequence comparison revealed that strain PM3T shared a high degree of 16S rRNA gene sequence similarity with Planomonospora sphaerica DSM 44632T (99.3%), Planomonospora parontospora subsp. parontospora DSM 43177T (99.2%) and P. parontospora subsp. antibiotica DSM 43869T (99.0%). DNA-DNA hybridization values between strain PM3T and the type strains of the closely related species were between 58.4 and 70.1%. The combination of phylogenetic analysis, DNA-DNA relatedness data, phenotypic characteristics and chemotaxonomic data support the conclusion that strain PM3T represents a novel species of the genus Planomonospora, for which the name Planomonospora algeriensis sp. nov. is proposed. The type strain is PM3T (=DSM 46752T = CECT 9047T).

Saccharothrix ghardaiensis sp. nov., an actinobacterium isolated from Saharan soil.

The taxonomic position of a new Saccharothrix strain, designated MB46T, isolated from a Saharan soil sample collected in Mzab region (Ghardaïa province, South Algeria) was established following a polyphasic approach. The novel microorganism has morphological and chemical characteristics typical of the members of the genus Saccharothrix and formed a phyletic line at the periphery of the Saccharothrix espanaensis subcluster in the 16S rRNA gene dendrograms. Results of the 16S rRNA gene sequence comparisons revealed that strain MB46T shares high degrees of similarity with S. espanaensis DSM 44229T (99.2%), Saccharothrix variisporea DSM 43911T (98.7%) and Saccharothrix texasensis NRRL B-16134T (98.6%). However, the new strain exhibited only 12.5-17.5% DNA relatedness to the neighbouring Saccharothrix spp. On the basis of phenotypic characteristics, 16S rRNA gene sequence comparisons and DNA-DNA hybridizations, strain MB46T is concluded to represent a novel species of the genus Saccharothrix, for which the name Saccharothrix ghardaiensis sp. nov. (type strain MB46T = DSM 46886T = CECT 9046T) is proposed.

Saccharothrix isguenensis sp. nov., an actinobacterium isolated from desert soil.

A novel actinobacterial strain, designated MB27T, was isolated from a Saharan soil sample collected in Mzab region (Ghardaïa province, South Algeria). Strain MB27T was characterized following a polyphasic taxonomic approach. This strain produced a branched and fragmented substrate mycelium, which was found to have a yellowish orange colour. A white scanty aerial mycelium was produced on most media tested. Chemotaxonomic and phylogenetic studies clearly demonstrated that strain MB27T belongs to the family Pseudonocardiaceae and is closely related to the genus Saccharothrix. Cell-wall hydrolysates contained meso-diaminopimelic acid but not glycine, and whole-cell hydrolysates contained galactose, glucose, ribose and small amounts of mannose and rhamnose. The detected phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. Mycolic acids were not detected while the predominant fatty acid was iso-branched hexadecanoate (iso-C16 : 0). The major menaquinone was MK-9(H4). Results of 16S rRNA gene sequence comparisons revealed that strain MB27T shairs the highest degree of similarity with Saccharothrix ecbatanensis DSM 45486T (99.8%), Saccharothrix hoggarensis DSM 45457T (99.3 %), Saccharothrix longispora DSM 43749T (98.6 %) and Saccharothrix yanglingensis DSM 45665T (98.6 %). However, it exhibited only 11-42 % DNA-DNA relatedness to the neighbouring Saccharothrixspecies. On the basis of phenotypic characteristics, 16S rRNA gene sequence comparisons and DNA-DNA hybridization, strain MB27T is shown to represent a novel species of the genus Saccharothrix, for which the name Saccharothrix isguenensis sp. nov. (type strain MB27T=DSM 46885T=CECT 9045T) is proposed.

Actinophytocola algeriensis sp. nov., an actinobacterium isolated from Saharan soil.

During our investigations of new actinobacterial taxa, a novel actinobacterial strain, designated MB20T, was isolated from a Saharan soil sample, collected in the Mzab region (Ghardaïa province, southern Algeria). In order to reveal its taxonomic position, the novel strain was characterized following a polyphasic taxonomic approach. It was noticed that strain MB20T produced white, branched and fragmented substrate mycelium with no aerial mycelium on most of the media tested. Chemotaxonomic and phylogenetic studies clearly demonstrated that strain MB20T belonged to the family Pseudonocardiaceae and was closely related to the genus Actinophytocola. Cell-wall hydrolysates contained meso-diaminopimelic acid but not glycine, and whole-cell hydrolysates contained galactose, glucose and ribose. The diagnostic phospholipid was phosphatidylethanolamine. Mycolic acids were not detected while the predominant fatty acid was found to be iso-branched hexadecanoate (iso-C16 : 0). The major menaquinone was MK-9(H4). Results of the 16S rRNA gene sequence comparison revealed that strain MB20T shared the highest degree of similarity with Actinophytocola gilvus DSM 45828T (98.5 %), Actinophytocola corallina DSM 45659T (98.0 %) and Actinophytocola timorensis DSM 45660T (97.5 %). However, DNA-DNA hybridization studies showed only 32.9 % similarity with A. timorensis, 23.7 % similarity with A. gilvus and 17.9 % similarity with A. corallina. On the basis of phenotypic characteristics, 16S rRNA gene sequence comparisons and DNA-DNA hybridization, strain MB20T was revealed to be a representative of a novel species of the genus Actinophytocola, for which the name Actinophytocola algeriensis sp. nov. (type strain MB20T =DSM 46746T =CECT 8960T) is proposed.

Streptosporangium becharense sp. nov., an actinobacterium isolated from desert soil.

The taxonomic position of a novel actinobacterium, strain SG1T, isolated from a Saharan soil sample collected from Béni-Abbès, Béchar (south-west Algeria), was established by using a polyphasic approach. The micro-organism had morphological and chemical features that were consistent with its classification in the genus Streptosporangium. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose and glucose, but not madurose. The predominant menaquinones were MK-9(H2) and MK-9(H4). The polar lipid profile contained diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylhydroxymethylethanolamine, phosphatidylhydroxyethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The predominant cellular fatty acids were C17 : 1ω8c, iso-C16 : 0, 10-methyl C17 : 0, C18 : 1ω9c and C17 : 0. 16S rRNA gene sequence similarity analysis supported the classification of the isolate in the genus Streptosporangium and indicated that it was related most closely to 'Streptosporangium subfuscum' DSM 46724 (99.7 % similarity), Streptosporangium pseudovulgare DSM 43181T (98.7 %), Streptosporangium fragile DSM 43847T (98.6 %) and Streptosporangium sandarakinum DSM 45763T (98.5 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SG1T formed a cluster with its closest relative 'S. subfuscum' DSM 46724. However, DNA-DNA relatedness as well as physiological and chemotaxonomical analyses showed that strain SG1T could be differentiated from its closest phylogenetic relatives. Therefore, it is proposed that strain SG1T should be classified as representing a novel species in the genus Streptosporangium, for which the name Streptosporangiumbecharense sp. nov. is proposed. The type strain is SG1T (=DSM 46887T=CECT 8961T).

Actinomadura adrarensis sp. nov., an actinobacterium isolated from Saharan soil.

A novel actinobacterial strain, designated ACD12T, was isolated from a Saharan soil sample collected from Adrar province, southern Algeria. A polyphasic study was carried out to establish the taxonomic position of this strain. Strain ACD12T was observed to form extensively branched substrate mycelia. Aerial mycelium was absent or was weakly produced on all media tested, while spore chains were short with a hooked and irregular spiral form (2-3 turns). The dominant diaminopimelic acid isomer in the cell wall was meso-diaminopimelic acid. Glucose, ribose, galactose, mannose and madurose occured in whole-cell hydrolysates. The major phospholipid was diphosphatidylglycerol and phosphatidylinositol. The predominant menaquinone was MK-9(H6). The fatty acid profile was characterized by the presence of C16 : 0, C17 : 0, C15 : 0, C18 : 0, C18 : 1 cis9 and iso-C16 : 0. Results of 16S rRNA gene sequence comparisons revealed that strain ACD12T shared the highest degree of 16S rRNA gene sequence similarity with Actinomadura sputi DSM 45233T (98.3 %) and Actinomadura hallensis DSM 45043T (97.8 %). All tree-making algorithms used also supported strain ACD12T forming a distinct clade with its most closely related species. In addition, DNA-DNA hybridization indicated only 39.8 % relatedness with A. sputi DSM 45233T and 18.7 % relatedness with A. hallensis DSM 45043T. The combined phenotypic and genotypic data show that the novel isolate represents a novel species of the genus Actinomadura, for which the name Actinomadura adrarensis sp. nov., is proposed, with the type strain ACD12T (=DSM 46745T =CECT 8842T).

Streptosporangium saharense sp. nov., an actinobacterium isolated from Saharan soil.

A novel actinobacterium, designated strain SG20T, was isolated from a Saharan soil sample collected from Béni-isguen (Mzab), Ghardaïa province, southern Algeria. The micro-organism developed small roundish sporangia on aerial mycelium that were sessile or carried by very short sporangiophores. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the whole-cell sugars comprised glucose, ribose and mannose, but madurose was not detected. The predominant menaquinones were MK-9(H4), MK-9(H6) and MK-9(H2). The major fatty acids were iso-C16 : 0 and C16 : 0. The phospholipids detected were diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine and unknown lipids. The phenotypic and chemotaxonomic characteristics of the novel strain resembled those of recognized members of the genus Streptosporangium. Moreover, phylogenetic analysis based on a 16S rRNA gene sequence generated from the strain identified its closest relative as Streptosporangium jomthongense BCC 53154T (98.5 % similarity), which produces single spores on aerial mycelium, but no sporangia. In hybridization experiments, the DNA-DNA relatedness values recorded between strain SG20T and S. jomthongense DSM 46822T fell well below 70 %. On the basis of phenotypic and genotypic data, strain SG20T can be distinguished as representing a novel species of the genus Streptosporangium, for which the name Streptosporangium saharense sp. nov. is proposed. The type strain is SG20T ( = DSM 46743T = CECT 8840T).

Actinomadura algeriensis sp. nov., an actinobacterium isolated from Saharan soil.

During the course of a screening programme for new taxa of actinobacteria, a strain designated ACD1(T), was isolated from a Saharan soil in the Hoggar region (Algeria). The taxonomic position of this strain was determined using a polyphasic taxonomic approach. The strain was observed to form extensively branched, non-fragmenting substrate mycelium, and aerial mycelium with straight to flexuous, hooked and irregular spirals (1-2 turns) forming short chains of spores. The diamino acid present in the cell wall is meso-diaminopimelic acid. Galactose, glucose, madurose, mannose and ribose occur in whole-cell hydrolysates. The diagnostic phospholipids detected were diphosphatidylglycerol and phosphatidylinositol. The major menaquinones were identified as MK-9 (H4) and MK-9 (H2). The major fatty acids were found to be C16:0, C18:1 cis9, iso-C16:0 and 10-methyl C18:0. Phylogenetic analysis based on the 16S rRNA gene showed that the strain belongs to the genus Actinomadura, and is closely related to Actinomadura sediminis DSM 45500(T) (98.5 % similarity) and Actinomadura cremea subsp. cremea DSM 43676(T) (98.3 % similarity). However, DNA-DNA hybridization revealed only 48.0 % relatedness with A. sediminis DSM 45500(T) and 33.2 % relatedness with A. cremea subsp. cremea DSM 43676(T). The combined phenotypic and genotypic data showed that the strain represents a novel species of the genus Actinomadura, for which the name Actinomadura algeriensis sp. nov. is proposed, with the type strain ACD1(T) (= DSM 46744(T) = CECT 8841(T)).

Thermoactinomyces khenchelensis sp. nov., a filamentous bacterium isolated from soil sediment of a terrestrial hot spring.

A novel thermophilic filamentous bacterium, designated strain T36(T), was isolated from soil sediment sample from a hot spring source collected in Khenchela province, Algeria. Strain T36(T) was identified as a member of the genus Thermoactinomyces by a polyphasic approach. Strain T36(T) was observed to form white aerial mycelium and non-coloured to pale yellow substrate mycelium, both producing endospores, sessile or borne by short sporophores. The optimum growth temperature and pH were found to be 37-55 °C and 7.0-9.0, respectively and the optimum NaCl concentration for growth was found to be 0-7 % (w/v). The diagnostic diamino acid in the cell wall peptidoglycan was identified as meso-diaminopimelic acid. The predominant menaquinone of strain T36(T) was identified as MK-7 (H0). The major fatty acids were found to be iso-C15:0 and iso-C17:0. The phospholipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphoglycolipid. The chemotaxonomic properties of strain T36(T) are consistent with those shared by members of the genus Thermoactinomyces. 16S rRNA gene sequence analysis indicated that the sequence similarities between strain T36(T) and Thermoactinomyces species with validly published names were less than 98 %. Based on the combined genotypic and phenotypic evidence, it is proposed that strain T36(T) should be classified as representative of a novel species, for which the name Thermoactinomyces khenchelensis sp. nov. is proposed. The type strain is T36(T) (=DSM 45951(T) = CECT 8579(T)).

Streptosporangium algeriense sp. nov., an actinobacterium isolated from desert soil.

The taxonomic position of a novel actinobacterium, strain 169T, isolated from a sample of Algerian Saharan soil, was determined using a polyphasic taxonomic approach. The aerial mycelium produced non-motile, round- to oval-shaped spores, with a smooth surface, which were sessile or carried by short sporophores. Chemotaxonomically, isolate 169T showed the same results as members of the genus Streptosporangium, but madurose, the so far diagnostic sugar of the genus, was not detected in the whole-cell hydrolysate. Despite the absence of sporangia, the 16S rRNA gene sequence analysis confirmed that strain 169T was a member of the genus Streptosporangium. Strain 169T was most closely related to Streptosporangium jomthongense NBRC 110047T (99.3 % 16S rRNA gene sequence similarity), which is the only non-sporangia-forming species reported among the genus. However, DNA-DNA hybridization studies with this species showed 60 % relatedness. Based upon genotypic and phenotypic data, a novel species, Streptosporangium algeriense sp. nov., is proposed, with 169T ( = DSM 45455T = MTCC 11561T = CCUG 62974T) as the type strain.

Bounagaea algeriensis gen. nov., sp. nov., an extremely halophilic actinobacterium isolated from a Saharan soil of Algeria.

A novel halophilic actinobacterium strain, designated H8(T), was isolated from a Saharan soil sample collected in El-Goléa, South Algeria. Strain H8(T) was identified as representing a new genus using a polyphasic taxonomic approach. Phylogenetic analysis revealed that strain H8(T) shared the highest degree of 16S rRNA gene sequence similarity with 'Mzabimyces algeriensis' DSM 46680(T) (93.0 %), Saccharopolyspora ghardaiensis DSM 45606(T) (91.2 %), Halopolyspora alba DSM 45976(T) (90.8 %) and Actinopolyspora mortivallis DSM 44261(T) (90.0 %). The strain was found to grow optimally at 28-35 °C, at pH 6.0-7.0, and in the presence of 15-25 % (w/v) NaCl. The substrate mycelium was observed to be well developed and fragmented in liquid medium and on solid medium. The aerial mycelium was observed to be moderately abundant and to form long chains with non-motile, smooth-surfaced and ovoid or spherical spores at maturity. The cell wall of strain H8(T) was found to contain meso-diaminopimelic acid. The whole-cell hydrolysates were found to mainly contain arabinose and galactose. The diagnostic phospholipid detected was phosphatidylcholine, and MK-9(H4), MK-9(H2) and MK-10(H2) were found to be the predominant menaquinones. The major cellular fatty acids were determined to be anteiso-C17:0 and iso-C15:0. The genomic DNA G+C content of strain H8(T) was determined to be 71.3 mol%. The genotypic and phenotypic data showed that the strain represents a novel genus and species, for which the name Bounagaea algeriensis gen. nov., sp. nov. is proposed, with the type strain H8(T) (=DSM 45966(T) = CECT 8470(T)).

Actinoalloteichus hoggarensis sp. nov., an actinomycete isolated from Saharan soil.

A moderately halophilic actinomycete strain, designated AH97T, was isolated from Saharan soil in the Hoggar region (south Algeria) and was subjected to polyphasic taxonomic characterization. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Actinoalloteichus. Results of 16S rRNA gene sequence comparison revealed that strain AH97T shared the highest degree of 16S rRNA gene sequence similarity with Actinoalloteichus hymeniacidonis DSM 45092T (99.3 %) and Actinoalloteichus nanshanensis DSM 45655T (98.7 %). However, DNA-DNA hybridization studies showed only 26.5 % relatedness with A. hymeniacidonis DSM 45092T and 28.0 % with A. nanshanensis DSM 45655T. The genotypic and phenotypic data showed that strain AH97T represents a novel species of the genus Actinoalloteichus, for which the name Actinoalloteichus hoggarensis sp. nov. is proposed, with AH97T ( = DSM 45943T = CECT 8639T) as the type strain.