Melghirimyces thermohalophilus sp. nov., a novel thermoactinomycete isolated from an Algerian salt lake

A novel filamentous bacterium designated Nari11AT was isolated from soil collected from a salt lake named Chott Melghir located in south east of Algeria. The strain is an aerobic, halophilic, thermotolerant, Gram-positive bacterium, growing at NaCl concentrations between 5 and 20% w/v and temperature and pH ranges between 43-60 °C and 5.0-10.0, respectively. The major fatty acids were isoC15:0, anteisoC15:0 and isoC17:0. The G+C value was 53.4 mol %. LL-diaminopimelic acid was the diamino acid of the peptidoglycan. The major menaquinone was MK-7, but MK-6 and MK-8 were also present in trace amounts. The polar lipids' profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and three unidentified phospholipids. Results of molecular and phenotypic analysis led to the description of the strain as a new member to the genus Melghirimyces, family Thermoactinomycetaceae. Strain Nari11AT shows a 16S rRNA gene sequence similarity of 96.7% with Melghirimyces algeriensis. On the basis of phenotypic, physiological and phylogenetical data the type strain Nari11AT (DSM 45514T =CCUG 60050T) represents a new species for which the name Melghirimyces thermohalophilus sp. nov., is proposed

Effect of Dietary n-3 Polyunsaturated Fatty Acids on Oxidant/Antioxidant Status in Macrosomic Offspring of Diabetic Rats

The aim of this work was to determine the effect of dietary n-3 PUFA on oxidant/antioxidant status, in vitro very low and low density lipoprotein (VLDL-LDL), and VLDL-LDL-fatty acid composition in macrosomic pups of diabetic mothers. We hypothesized that n-3 PUFA would improve oxidative stress in macrosomia. Diabetes was induced in female Wistar rats fed with the ISIO diet (control) or with the EPAX diet (enriched in n-3 PUFAs), by streptozotocin. The macrosomic pups were killed at birth (day 0) and at adulthood (day 90). Lipid parameters and VLDL-LDL-fatty acid composition were investigated. The oxidant/antioxidant status was determined by measuring plasma oxygen radical absorbance capacity (ORAC), hydroperoxides, carbonyl proteins, and VLDL-LDL oxidation. Macrosomic rats of ISIO fed diabetic mothers showed an increase in plasma and VLDL-LDL-triglycerides and VLDL-LDL-cholesterol levels and altered VLDL-LDL-fatty acid composition. Plasma ORAC was low with high hydroperoxide and carbonyl protein levels. The in vitro oxidizability of VLDL-LDL was enhanced in these macrosomic rats. The EPAX diet corrected lipid parameters and improved oxidant/antioxidant status but increased VLDL-LDL susceptibility to oxidation. Macrosomia is associated with lipid abnormalities and oxidative stress. n-3 PUFA exerts favorable effects on lipid metabolism and on the oxidant/antioxidant status of macrosomic rats. However, there are no evident effects on VLDL-LDL oxidation

Isolation and characterization of halophilic archaea able to produce biosurfactants

Halotolerants microorganisms able to live in saline environments, offer a multitude of actual or potential applications in various fields of biotechnology. This is why some strains of Halobacteria from an Algerian culture collection were screened for biosurfactant production in a standard medium using the qualitative drop-collapse test and emulsification activity assay. Five of the Halobacteria strains reduced the growth medium surface tension below 40mNm-1 and two of them exhibited high emulsion-stabilising capacity. Diesel oil-in-water emulsions were stabilized over a broad range of conditions, from pH 2 to 11, with up to 35% sodium chloride or up to 25% ethanol in the aqueous phase. Emulsions were stable to three cycles of freezing and thawing. The components of the biosurfactant were determined; it contains sugar, protein and lipid. The two Halobacteria strains with enhanced biosurfactants producers designed strain A21 and strain D21 were selected to identify by phenotypic, biochemical characteristics and by partial 16S rRNA gene sequencing. The strains have Mg2+and salt growth requirements are always above 15% (w/v) salts with an optimal concentration of 15% to 20%. Analyses of partial 16S rRNA gene sequences of the two strains suggested that they were halophiles belonging to genera of the family Halobacteriaceae, Halovivax (strain A21) and Haloarcula (strain D21). To our knowledge, this a first report of biosurfactant production at such a high salt concentratio

Caldicoprobacter algeriensis sp nov a new thermophilic anaerobic, xylanolytic bacterium isolated from an Algerian hot spring

A thermophilic anaerobic bacterium (strain TH7C1(T)) was isolated from the hydrothermal hot spring of Guelma in the northeast of Algeria. Strain TH7C1(T) stained Gram-positive, was a non-motile rod appearing singly, in pairs, or as long chains (0.7-1 x 2-6 mu m(2)). Spores were never observed. It grew at temperatures between 55 and 75A degrees C (optimum 65A degrees C) and at pH between 6.2 and 8.3 (optimum 6.9). It did not require NaCl for growth, but tolerated it up to 5 g l(-1). Strain TH7C1(T) is an obligatory heterotroph fermenting sugars including glucose, galactose, lactose, raffinose, fructose, ribose, xylose, arabinose, maltose, mannitol, cellobiose, mannose, melibiose, saccharose, but also xylan, and pyruvate. Fermentation of sugars only occurred in the presence of yeast extract (0.1%). The end-products from glucose fermentation were acetate, lactate, ethanol, CO2, and H-2. Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate, and sulfite were not used as electron acceptors. The G+C content of the genomic DNA was 44.7 mol% (HPLC techniques). Phylogenetic analysis of the small-subunit ribosomal RNA (rRNA) gene sequence indicated that strain TH7C1(T) was affiliated to Firmicutes, order Clostridiales, family Caldicoprobacteraceae, with Caldicoprobacter oshimai (98.5%) being its closest relative. Based on phenotypic, phylogenetic, and genetic characteristics, strain TH7C1(T) is proposed as a novel species of genus Caldicoprobacter, Caldicoprobacter algeriensis, sp. nov. (strain TH7C1(T) = DSM 22661(T) = JCM 16184(T))

Novel serine keratinase from Caldicoprobacter algeriensis exhibiting outstanding hide dehairing abilities

The current paper reports on the purification of an extracellular thermostable keratinase (KERCA) produced from Caldicoprobacter algeriensis strain TH7C1(T), a thermophilic, anaerobic bacterium isolated from a hydrothermal hot spring in Algeria. The maximum keratinase activity recorded after 24-h of incubation at 50 degrees C was 21000 U/ml. The enzyme was purified by ammonium sulfate precipitation-dialysis and heat treatment (2 h at 50 degrees C) followed by UNO Q-6 FPLC anion exchange chromatography, and submitted to biochemical characterization assays. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer with a molecular mass of 33246.10 Da. The sequence of the 23 N-terminal residues of KERCA showed high homology with those of bacterial keratinases. Optimal activity was achieved at pH 7 and 50 degrees C. The enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggests that it belongs to the serine keratinase family. KERCA displayed higher levels of hydrolysis and catalytic efficiency than keratinase KERQ7 from Bacillus tequilensis strain Q7. These properties make KERCA a potential promising and eco-friendly alternative to the conventional chemicals used for the dehairing of goat, sheep, and bovine hides in the leather processing industry

Biochemical characterization of a detergent-stable serine alkaline protease from Caldicoprobacter guelmensis

Caldicoprobacter guelmensis isolated from the hydrothermal hot spring of Guelma (Algeria) produced high amounts of extracellular thermostable serine alkaline protease (called SAPCG) (23,000 U/mL). The latter was purified by ammonium sulphate precipitation, UNO Q-6 FPLC and Zorbex PSM 300 HPLC, and submitted to biochemical characterization assays. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer, with a molecular mass of 55,824.19 Da. The 19 N-terminal residue sequence of SAPCG showed high homology with those of microbial proteases. The enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggested its belonging to the serine protease family. It showed optimum protease activity at pH 10 and 70 degrees C with casein as a substrate. The thermoactivity and thermostability of SAPCG were enhanced in the presence of 2 mM Ca2+. Its half-life times at 80 and 90 degrees C were 180 and 60 min, respectively. Interestingly, the SAPCG protease exhibited significant compatibility with iSiS and Persil, and wash performance analysis revealed that it could remove bloodstains effectively. Overall, SAPCG displayed a number of attractive properties that make it a promising candidate for future applications as an additive in detergent formulations