Encapsulation of biological active phenolic compounds extracted from wine wastes in alginate-chitosan microbeads.

Grapes (Vitis vinifera) are produced in large amounts worldwide and mostly are used for winemaking. Their untreated wastes are rich in valuable secondary metabolites, such as phenolics. Thus, in this study, white and red wine wastes (Malagouzia and Syrah variety) were investigated for their added value phenolics, which were analysed by high performance liquid chromatography (HPLC) and electrospray ionisation-mass spectrometry (ESI/MS) and subsequently encapsulated in several polymers. Extracts from all wastes gave high amounts of total phenolics (13 ± 2.72-22 ± 2.69 mg g-1) and possessed high antioxidant activity (67-97%). In addition to their significant antibacterial activity against gram-negative and gram-positive bacteria, interesting results were also obtained from their anti-inflammatory and antiplatelet activity, in vitro. Encapsulation of the extracts was selective, leaving out most of sugars and other organic compounds when alginate-chitosan was used. Encapsulation efficiency recorded for all extracts ranged from 55% to 79%. Release studies were also performed in several solutions aiming in their commercial use in food and pharmaceutical industries.

Natural Origin Lycopene and Its "Green" Downstream Processing.

Lycopene is an abundant natural carotenoid pigment with several biological functions (well-known for its antioxidant properties) which is under intensive investigation in recent years. Lycopene chemistry, its natural distribution, bioavailability, biological significance, and toxicological effects are briefly outlined in the first part of this review. The second, major part, deals with various modern downstream processing techniques, which are assessed in order to identify promising approaches for the recovery of lycopene and of similar lipophilic compounds. Natural lycopene is synthesized in plants and by microorganisms, with main representatives of these two categories (for industrial production) tomato and its by-products and the fungus Blakeslea trispora, respectively. Currently, there is a great deal of effort to develop efficient downstream processing for large scale production of natural-origin lycopene, with trends strongly indicating the necessity for "green" and mild extraction conditions. In this review, emphasis is placed on final product safety and ecofriendly processing, which are expected to totally dominate in the field of natural-origin lycopene extraction and purification.

Detailed study of the dielectric function of a lysozyme solution studied with molecular dynamics simulations.

The spread of microwave technology and new microwave applications in medicine have revitalized interest in the dielectric behavior of biological systems. In this work, the Fröhlich-Kirkwood approach and the linear response theory have been applied in conjunction with molecular dynamics simulations to study the dielectric response of a lysozyme solution as a model. The overall experimental dielectric behavior of a 9.88 mM lysozyme solution has been reproduced in a quantitative manner by employing a method based on the decomposition of the hydration shells close to the solute. Detailed analysis of the calculated spectra identified two δ-processes located at 200 MHz (δ1) and about 1 GHz (δ2), respectively. δ1 is associated mainly with the first hydration shell, while δ2 mainly with bulk water and the second hydration shell. Moreover, indications for the existence of an even faster relaxation in the 10(11)-Hz frequency range were found for the first time. Finally, the static dielectric constants of lysozyme and its first and second hydration shells were calculated based on the Fröhlich-Kirkwood and the linear response theory approaches.

Bioremoval of heavy metals by bacterial biomass.

Heavy metals are among the most common pollutants found in the environment. Health problems due to the heavy metal pollution become a major concern throughout the world, and therefore, various treatment technologies such as reverse osmosis, ion exchange, solvent extraction, chemical precipitation, and adsorption are adopted to reduce or eliminate their concentration in the environment. Biosorption is a cost-effective and environmental friendly technique, and it can be used for detoxification of heavy metals in industrial effluents as an alternative treatment technology. Biosorption characteristics of various bacterial species are reviewed here with respect to the results reported so far. The role of physical, chemical, and biological modification of bacterial cells for heavy metal removal is presented. The paper evaluates the different kinetic, equilibrium, and thermodynamic models used in bacterial sorption of heavy metals. Biomass characterization and sorption mechanisms as well as elution of metal ions and regeneration of biomass are also discussed.

Autolysis of Blakeslea trispora during carotene production from cheese whey in an airlift reactor.

The phenomenon of autolysis in Blakeslea trispora during carotene production from deproteinized hydrolyzed whey in an airlift reactor was investigated. The process of cellular autolysis was studied by measuring the changes in carotene concentration, dry biomass, residual sugars, pH, intracellular protein, specific activity of the hydrolytic enzymes (proteases, chitinase), and micromorphology of the fungus using a computerized image analysis system. All these parameters were useful indicators of autolysis, but image analysis was found to be the most useful indicator of the onset and progress of autolysis in the culture. Autolysis of B. trispora began early in the growth phase, continued during the stationary phase, and increased significantly in the decline phase. The morphological differentiation of the fungus was a result of the degradation of the cell membrane by hydrolytic enzymes. The biosynthesis of carotenes was carried out in the exponential phase, where the phenomenon of autolysis was not intense.

Peptide analogues of 1811-1818 loop of the A3 subunit of the light chain A3-C1-C2 of FVIII of blood coagulation: biological evaluation.

Factor VIII, the plasma protein deficient or defective in individuals with hemophilia A, is a critical member of the blood coagulation cascade. Recent studies have identified the FVIII light chain region Glu1811-Lys1818 as being involved in FIXa binding and in the assembly of the FX-activating FIXaz-FVIIIa complex. Based on this, a series of 12 peptides, analogues of the 1811-1818 loop of the A3 subunit of the light chain A3-C1-C2 of FVIIIa, were synthesized and evaluated for their anticoagulant activity. Only peptide Ac-ETKTYFWK-NH(2) showed significant anticoagulant activity by inhibiting about 40% factor VIII at a concentration of 0.43 mM. It also showed a prolongation of activated partial thromboplastin time of 6.1 s, whereas its effect on prothrombin time measurements was meaningless. All the other peptides did not show any measurable effect at the concentration of 0.43 mM. These findings are encouraging though further investigation of the effect of this active peptide in different biological settings is needed in order to evaluate its possible clinical applications.

Comparative studies on the degradation of three aromatic compounds by Pseudomonas sp. and Staphylococcus xylosus.

Biological methods of wastewater treatment have been proved very effective for bioremediation of polluted sites. In this study, the degrading abilities of two bacteria Pseudomonas sp. and Staphylococcus xylosus, towards 1,2-dichlorobenzene (1,2-DCB), 2,4-dichlorophenol (2,4-DCP) and 4-Cl-m-cresol, are compared. Culture history and the presence of glucose as carbon source have been used for the optimization of cell's performance. 1,2-DCB showed the higher values of effective concentration (EC(50)), 1.04 and 0.84 mM with Pseudomonas sp. and S. xylosus respectively, whereas no substrate-inhibition appeared, in contrary to 4-Cl-m-cresol, that was more persistent in biodegradation by both bacteria. 2,4-DCP was less assimilated compared to 1,2-DCB, whereas bacterial specificity was higher, as it was found by the estimation of the half-saturation constant of 0.36 and 0.26 mM with Pseudomonas sp. and S. xylosus, respectively.

Molecularly imprinted polymers for RGD selective recognition and separation.

Molecularly imprinted polymers that could recognize the tripeptide Arg-Gly-Asp have been produced with the use of two functional monomers and three different cross-linkers, respectively. Methacrylic acid and acrylamide were used as functional monomers and the role of the ethylene glycol dimethacrylate, trimethylpropane trimethacrylate and N,N'-methylene-bisacrylamide as crosslinking monomers, was investigated on their recognition capability. The % net rebinding and the imprinting factor values were obtained, giving for the methacrylic acid-trimethylpropane trimethacrylate polymer the highest values 12.3% and 2.44, respectively. In addition, this polymer presented lower dissociation constant (K(D)) value and the higher B (max)% of theoretical total binding sites than all the other polymers. Rebinding experiments with Lys-Gly-Asp, an analogue of Arg-Gly-Asp, and other different peptides, such as cholecystokinin C-terminal tri- and pentapeptide and gramicidin, further indicated the selectivity of methacrylic acid-trimethylpropane trimethacrylate copolymer for Arg-Gly-Asp giving specific selectivity factor values 1.27, 1.98, 1.31 and 1.67, respectively.

Heterologous expression of a hyperthermophilic alpha-amylase in xanthan gum producing Xanthomonas campestris cells.

A hyperthermophilic alpha-amylase encoding gene from Pyrococcus woesei was transferred and expressed in Xanthomonas campestris ATCC 13951. The heterologous alpha-amylase activity was detected in the intracellular fraction of X. campestris and presented similar thermostability and catalytic properties with the native P. woesei enzyme. The recombinant alpha-amylase was found to be stable at 90 degrees C for 4 h and within the same period it retained more than 50% of its initial activity at 110 degrees C. Furthermore, X. campestris transformants produced similar levels of recombinant alpha-amylase activity regardless of the carbon source present in the growth medium, whereas the native X. campestris alpha-amylase production was highly dependent on starch availability and it was suppressed in the presence of glucose or other reducing sugars. On the other hand, xanthan gum yield, which appeared to be similar for both wild type and recombinant X. campestris strains, was enhanced at higher starch or glucose concentrations. Evidence presented in this study supports that X. campestris is a promising cell factory for the co-production of recombinant hyperthermophilic alpha-amylase and xanthan gum.

Co-production of alpha-amylase and beta-galactosidase by Bacillus subtilis in complex organic substrates.

Various nutrients belonging to three categories, carbon, organic nitrogen and complex organic sources, were investigated for the first time in terms of their effect on the co-production of extracellular thermostable alpha-amylase and beta-galactosidase by Bacillus subtilis, a bacterium isolated from fresh sheep's milk. Among the organic nitrogen sources tested, tryptone and corn steep liquor favored their production. Substitution of soluble starch by various starchy substrates, such as corn flour, had a positive effect on both enzyme yields. Furthermore, a two-fold higher production of both enzymes was achieved when corn steep liquor or tryptone was used in combination with the different flours. Among the divalent cations examined, calcium ions appeared to be vital for alpha-amylase production. The crude alpha-amylase and beta-galactosidase produced by this B. subtilis strain exhibited maximal activities at 135 degrees C and 65 degrees C, respectively, and were also found to be significantly stable at elevated temperatures.

Frequency Dependent Non- Thermal Effects of Oscillating Electric Fields in the Microwave Region on the Properties of a Solvated Lysozyme System: A Molecular Dynamics Study.

The use of microwaves in every day's applications raises issues regarding the non thermal biological effects of microwaves. In this work we employ molecular dynamics simulations to advance further the dielectric studies of protein solutions in the case of lysozyme, taking into consideration possible frequency dependent changes in the structural and dynamic properties of the system upon application of electric field in the microwave region. The obtained dielectric spectra are identical with those derived in our previous work using the Fröhlich-Kirkwood approach in the framework of the linear response theory. Noticeable structural changes in the protein have been observed only at frequencies near its absorption maximum. Concerning Cα position fluctuations, different frequencies affected different regions of the protein sequence. Furthermore, the influence of the field on the kinetics of protein-water as well as on the water-water hydrogen bonds in the first hydration shell has been studied; an extension of the Luzar-Chandler kinetic model was deemed necessary for a better fit of the applied field results and for the estimation of more accurate hydrogen bond lifetime values.

Agro-food wastes utilization by Blakeslea trispora for carotenoids production.

The all-trans-ß-carotene is a natural pigment used in various industrial fields (food, cosmetics, pharmaceuticals, etc) and possesses the higher provitamin A activity, in respect to other carotenoids. All-trans-ß-carotene is produced industrially by chemical and biotechnological means. For ß-carotene biotechnological production in industrial scale mated cultures of Blakeslea trispora, a heterothallic fungus, are mainly used. Despite the intense research for ß-carotene production by B. trispora, natural substrate utilization has not been extensively studied. Solid agro-food wastes such as cabbage, watermelon husk and peach peels from northern Greece as main carbon source into submerged B. trispora cultures for carotenoids production, was examined. The media containing only the agro-food waste (2-4) gave a biomass accumulation 7.77 ± 0.4 g/L, while a reference medium 1 with glucose (10 g/L) gave 4.65 ± 0.21 g/L. In another experiments series agro-food wastes were used with corn steep liquor and thiamine (media 6-8), giving a biomass accumulation and total carotenoid volumetric production 10.2 ± 2.41 g/L and 230.49 ± 22.97 mg/L, respectively. These are the higher values reported for solid wastes so far in respect to those obtained from a synthetic medium, with higher glucose concentration of 50 g/L where the correspondent values were 9.41 ± 1.18 g/L and 45.63 mg/L respectively. The results support that B. trispora is able to utilize, almost equivalently, different origin agro-food wastes for carotenoids production. Furthermore, ß-carotene percentage in all examined cases was over 76%, as it was estimated by HPLC analysis, suggesting that these agro food wastes may be used for high purity, large scale ß carotene production.

Raman spectroscopy for intracellular monitoring of carotenoid in Blakeslea trispora.

In the present study, we explore the feasibility of Raman spectroscopy for intracellular monitoring of carotenoid in filamentous fungi Blakeslea trispora. Although carotenoid production from this fungus has been extensively studied through various chromatographic methods and ultraviolet-visible spectroscopy, no intracellular monitoring has been demonstrated until now. The intensity of the Raman spectrum, and more conveniently that of the strongest nu(1) carotenoid band at approximately 1,519 cm(-1), exhibits a good linear correlation with the carotenoid content of the sample as determined by high-performance liquid chromatography (HPLC) and ultraviolet-visible (UV-Vis) spectroscopy. Our results suggest that Raman spectroscopy can serve as an alternative method for the study and quantification of carotenoid in batch-mated submerged cultivations of B. trispora and similar organisms. Although not as accurate as HPLC, it allows a rapid sampling and analysis, avoiding the prolonged and tedious classical isolation procedures required for carotenoid determination by HPLC and UV-Vis spectroscopy.