Degradative actions of microbial xylanolytic activities on hemicelluloses from rhizome of Arundo donax

Polysaccharidases from extremophiles are remarkable for specific action, resistance to different reaction conditions and other biotechnologically interesting features. In this article the action of crude extracts of thermophilic microorganisms (Thermotoga neapolitana, Geobacillus thermantarcticus and Thermoanaerobacterium thermostercoris) is studied using as substrate hemicellulose from one of the most interesting biomass crops, the giant reed (Arundo donax L.). This biomass can be cultivated without competition and a huge amount of rhizomes remains in the soil at the end of cropping cycle (10–15 years) representing a further source of useful molecules. Optimization of the procedure for preparation of the hemicellulose fraction from rhizomes of Arundo donax, is studied. Polysaccharidases from crude extracts of thermophilic microorganisms revealed to be suitable for total degradative action and/or production of small useful oligosaccharides from hemicelluloses from A. donax. Xylobiose and interesting tetra- and pentasaccharide are obtained by enzymatic action in different conditions. Convenient amount of raw material was processed per mg of crude enzymes. Raw hemicelluloses and pretreated material show antioxidant activity unlike isolated tetra- and pentasaccharide. The body of results suggest that rhizomes represent a useful raw material for the production of valuable industrial products, thus allowing to increase the economic efficiency of A. donax cultivation.

Antioxidant and cytotoxic activities investigation of tomato seed extracts

Biological activities of different varieties of tomato seed extracts were evaluated to verify the potential antioxidant and/or antiproliferative activity of the bioactive metabolites present in them. Findings demonstrated that among all the varieties investigated (San Marzano Rosso, San Marzano Giallo, Corbarino, Black Tomato and San Marzano/Black Tomato hybrid) San Marzano Rosso seed extract exhibited the highest free radical-scavenging activity with 68% of 2,2-Diphenyl-1-picrylhydrazyl radical inhibition, and the best cytotoxic activity evaluated by using the brine shrimp test (LD50: 23,198 ppm) and 3-(4,5-dimethylthiazol-2-yl)-2,5-phenyl-2H-tetrazolium bromide assay on A375 cell line (IC50: 137.7 μg/mL).

Bioactivity of tomato hybrid powder: antioxidant compounds and their biological activities

The antioxidant and cytotoxic activities and the polyphenolic and anthocyanin contents of tomato hybrid powders were studied. Tomato powders were obtained, starting from the fresh fruits that had undergone an industrial process of drying and pulverization at two different temperatures. Antioxidant activities were evaluated in different extracts by using spectrophotometric assays: 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid and N,N-dimethyl-p-phenylenediamine dihydrochloride cation radical inhibition for lipophilic and hydrophilic extracts, respectively, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay for polyphenolic extracts. Moreover, polyphenolic and anthocyanin contents were also carried out to detect the presence of these bioactive compounds. The effect of cytotoxic activity in vitro of tomato hybrid powder extracts on T47D (human breast carcinoma) cells was also evaluated. Results showed good antioxidant activities in lipophilic, polyphenolic, and hydrophilic extracts of samples that were obtained at a lower temperature. Extracts of the sample obtained at a higher temperature presented moderate antioxidant activity, lower than the extracts of other samples, which was probably due to the loss of labile antioxidant compounds during the industrial process. Very interesting was the presence of anthocyanins in both samples, even if in traces, and also a moderate cytotoxicity of a lipophilic extract on T47D cells. Therefore, tomato hybrid powders, on the basis of their multifunctional properties, could have a biotechnological application in agri-food or cosmetic industries as an additive for improving nutritional and/or bioactive qualities of commercial products used in daily nutrition and cosmetics.

The Lipid A from the haloalkaliphilic bacterium Salinivibrio sharmensis strain BAG(T)

Lipid A is a major constituent of the lipopolysaccharides (or endotoxins), which are complex amphiphilic macromolecules anchored in the outer membrane of Gram-negative bacteria. The glycolipid lipid A is known to possess the minimal chemical structure for LPSs endotoxic activity, able to cause septic shock. Lipid A isolated from extremophiles is interesting, since very few cases of pathogenic bacteria have been found among these microorganisms. In some cases their lipid A has shown to have an antagonist activity, i.e., it is able to interact with the immune system of the host without triggering a proinflammatory response by blocking binding of substances that could elicit such a response. However, the relationship between the structure and the activity of these molecules is far from being completely clear. A deeper knowledge of the lipid A chemical structure can help the understanding of these mechanisms. In this manuscript, we present our work on the complete structural characterization of the lipid A obtained from the lipopolysaccharides (LPS) of the haloalkaliphilic bacterium Salinivibrio sharmensis. Lipid A was obtained from the purified LPS by mild acid hydrolysis. The lipid A, which contains different number of fatty acids residues, and its partially deacylated derivatives were completely characterized by means of electrospray ionization Fourier transform ion cyclotron (ESI FT-ICR) mass spectrometry and chemical analysis.

Flocculating performances of exopolysaccharides produced by a halophilic bacterial strain cultivated on agro-industrial waste

This study reports the first systematic investigation of the flocculation dynamics of exopolysaccharides (EPSs) produced by a halophilic bacterial strain grown on pretreated molasses as fermentation substrate. The potential use of these EPSs as an easily biodegradable, natural alternative for synthetic polyelectrolytes which are widely used and contain toxic and carcinogenic monomers was investigated. Flocculating activities of the EPS samples in synthetic water, synthetic sea water and natural sea water media which were used as model raw waters were monitored via the Photometric Dispersion Analyser (PDA 2000) instrument and removals were determined by measuring residual turbidities. One of the six EPS specimens, which formed the largest flocs thus performed highest turbidity removal, exhibited flocculation performance and particle removal efficiency comparable with commercial cationic, nonionic and anionic synthetic polyelectrolytes.

Exopolysaccharides from extremophiles: from fundamentals to biotechnology

Exopolysaccharides (EPSs) make up a substantial component of the extracellular polymers surrounding most microbial cells in extreme environments like Antarctic ecosystems, saline lakes, geothermal springs or deep sea hydrothermal vents. The extremophiles have developed various adaptations, enabling them to compensate for the deleterious effects of extreme conditions, e.g. high temperatures, salt, low pH or temperature, high radiation. Among these adaptation strategies, EPS biosynthesis is one of the most common protective mechanisms. The unusual metabolic pathways revealed in some extremophiles raised interest in extremophilic microorganisms as potential producers of EPSs with novel and unusual characteristics and functional activities under extreme conditions. Even though the accumulated knowledge on the structural and theological properties of EPSs from extremophiles is still very limited, it reveals a variety in properties, which may not be found in more traditional polymers. Both extremophilic microorganisms and their EPSs suggest several biotechnological advantages, like short fermentation processes for thermophiles and easily formed and stable emulsions of EPSs from psychrophiles. Unlike mesophilic producers of EPSs, many of them being pathogenic, extremophilic microorganisms provide non-pathogenic products, appropriate for applications in the food, pharmaceutical and cosmetics industries as emulsifiers, stabilizers, gel agents, coagulants, thickeners and suspending agents. The commercial value of EPSs synthesized by microorganisms from extreme habitats has been established recently.

Chemical Composition of Two Exopolysaccharides from Bacillus thermoantarcticus

The thermophilic bacterium Bacillus thermoantarcticus produces two exocellular polysaccharides (EPS 1 and EPS 2), which can be obtained from the supernatant of liquid cultures by cold-ethanol precipitation, in yields as high as 400 mg liter(sup-1). The EPS fraction was produced with all substrates tested, although a higher yield was obtained with mannose as the carbon and energy source. The EPS content was proportional to the total biomass. On a weight basis, EPS 1 and EPS 2 represented about 27 and 71%, respectively, of the total carbohydrate fraction. EPS 1 is a sulfate heteropolysaccharide containing mannose and glucose in a relative molar proportion of 1.0 and 0.7, respectively. EPS 2 is a sulfate homopolysaccharide containing mannose as the major component. The absolute configurations of hexoses were shown to be d for both EPSs. Nuclear magnetic resonance spectra confirmed the presence of (alpha)-d-mannose and (beta)-d-glucose in EPS 1 and only (alpha)-d-mannose in EPS 2. In addition, (sup1)H nuclear magnetic resonance analysis and chemical analysis indicated the presence of pyruvic acid in EPS 2.

Bacterial exopolysaccharides from extreme marine habitats: production, characterization and biological activities

Many marine bacteria produce exopolysaccharides (EPS) as a strategy for growth, adhering to solid surfaces, and to survive adverse conditions. There is growing interest in isolating new EPS producing bacteria from marine environments, particularly from extreme marine environments such as deep-sea hydrothermal vents characterized by high pressure and temperature and heavy metal presence. Marine EPS-producing microorganisms have been also isolated from several extreme niches such as the cold marine environments typically of Arctic and Antarctic sea ice, characterized by low temperature and low nutrient concentration, and the hypersaline marine environment found in a wide variety of aquatic and terrestrial ecosystems such as salt lakes and salterns. Most of their EPSs are heteropolysaccharides containing three or four different monosaccharides arranged in groups of 10 or less to form the repeating units. These polymers are often linear with an average molecular weight ranging from 1 × 10⁵ to 3 × 10⁵ Da. Some EPS are neutral macromolecules, but the majority of them are polyanionic for the presence of uronic acids or ketal-linked pyruvate or inorganic residues such as phosphate or sulfate. EPSs, forming a layer surrounding the cell, provide an effective protection against high or low temperature and salinity, or against possible predators. By examining their structure and chemical-physical characteristics it is possible to gain insight into their commercial application, and they are employed in several industries. Indeed EPSs produced by microorganisms from extreme habitats show biotechnological promise ranging from pharmaceutical industries, for their immunomodulatory and antiviral effects, bone regeneration and cicatrizing capacity, to food-processing industries for their peculiar gelling and thickening properties. Moreover, some EPSs are employed as biosurfactants and in detoxification mechanisms of petrochemical oil-polluted areas. The aim of this paper is to give an overview of current knowledge on EPSs produced by marine bacteria including symbiotic marine EPS-producing bacteria isolated from some marine annelid worms that live in extreme niches.

Acetamide derivatives with antioxidant activity and potential anti-inflammatory activity

This study reports the synthesis and antioxidant activity of some new acetamide derivatives. The compounds' structures were elucidated by NMR analysis and their melting points were measured. The in vitro antioxidant activity of these compounds was tested by evaluating the amount of scavenged ABTS radical and estimating ROS and NO production in tBOH- or LPS-stimulated J774.A1 macrophages. All compounds were tested for their effect on cell viability by an MTT assay and by a Brine Shrimp Test.

Anoxybacillus thermarum sp. nov., a novel thermophilic bacterium isolated from thermal mud in Euganean hot springs, Abano Terme, Italy

A novel aerobe thermophilic endospore-forming bacterium designated strain AF/04(T) was isolated from thermal mud located in Euganean hot springs, Abano Terme, Padova, Italy. Strain AF/04(T) was Gram-positive, motile, rod-shaped, occurring in pairs, or filamentous. The isolate grew between 55 and 67 degrees C (optimum 65 degrees C) and at pH 6.0-7.5 (optimum pH 7.2). The strain was aerobic and grew on maltose, trehalose, and sodium acetate as sole carbon sources. The G + C content of DNA was 53.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain AF/04(T) falls within the genus Anoxybacillus. Levels of 16S rRNA gene sequence similarity between strain AF/04(T) and the type strains of recognized Anoxybacillus species ranged from 95 to 99%. Chemotaxonomic data (major isoprenoid quinone-menaquinone-7; major fatty acid iso-C15:0 and anteiso-C17:0) supported the affiliation of strain AF/04(T) to the genus Anoxybacillus. Based on phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence analysis and DNA-DNA hybridization data, it was proposed that strain AF/04(T) (=DSM 17141(T) = ATCC BAA 1156(T)) should be placed in the genus Anoxybacillus as the type strain of a novel species, Anoxybacillus thermarum sp. nov.