A Novel Serine Metallokeratinase from a Newly Isolated <Emphasis Type="BoldItalic">Bacillus pumilus</Emphasis> A1 Grown on Chicken Feather Meal: Biochemical and Molecular Characterization

A keratinolytic enzyme (KerA1) secreted by a newly isolated Bacillus pumilus strain A1 cultivated in medium containing chicken feather meal was purified and characterized, and the gene was isolated and sequenced. The molecular mass of the purified enzyme was estimated to be 34,000 Da by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and gel filtration. The optimum pH and temperature for the purified keratinase were 9.0 and 60 °C, respectively, using keratin as a substrate. KerA1 showed a high stability towards nonionic surfactants. It was found to be relatively stable toward the strong anionic surfactant (SDS). The deduced amino acid sequence of the keratinase KerA1 differs from both the organic solvent tolerant protease of B. pumilus 115b and the dehairing protease of B. pumilus UN-31-C-42 by one and nine amino acids, respectively. These results suggest that this keratinase may be a useful alternative and ecofriendly route for handling the abundant amount of waste feathers and for applications in detergent formulations.     

Phase diagram and critical fields of organic quasi-1d superconductors in an applied magnetic field

No consensus has been reached about the symmetry of the Bechgaard salts superconducting phase. An RG analysis is in favor of interactions dominant in the singlet channel, but very close and sub-dominant in the triplet channel. We study the properties, in a magnetic field along the b′ direction, of a d-wave singlet phase, as well as of an f-wave triplet phase. Recent data about NMR Knight shift, as well as upper critical fields have brought strong indications about the possible symmetries. We have analyzed theoretically the consequences of these experimental data: our results are in favor of a singlet phase in low field, but of a triplet phase in large fields.     

The Constitutive Production of Pectinase by the CT1 Mutant of Penicillium Occitainis is Modulated by pH

The aim of the present study was to investigate pectinases production by CT1 mutant of Penicillium occitanis on glucose based media. Two main groups of pectinases were followed: lyases (pectin and pectate lyases) and hydrolases (polygalacturonases and polymethylgalacturonases). When cultivated in different liquid media, where either the starting glucose concentration or the nature of nitrogen sources used was varied, the CT1 mutant secreted either lyases or hydrolases. In fact, the pH of these various media seemed to correlate with the activity produced: The lyases were highly and exclusively produced at neutral or alkaline ambient pH, whereas hydrolases were highly produced on acidic ambient pH. Such conclusion was confirmed by following pectinase production in the same culture medium (with the same glucose concentration and the same nitrogen source) set at two initial pH of 4 and 7. Altogether, these results suggest that the pectinases control by PacC signaling pathway of P. occitanis should resemble to that of Aspergillus and its ability to “activate the expression of alkaline-expressed genes and repress acid-expressed genes” remains intact in the CT1 over-producing and constitutive strain. Enzymes produced at acidic pH (hydrolases) and at neutral pH (lyases) were applied in the hydrolysis of orange peel and gave results comparable to commercial enzymes.     

Solvent-Stable Digestive Alkaline Proteinases from Striped Seabream (<Emphasis Type="Italic">Lithognathus mormyrus</Emphasis>) Viscera: Characteristics,Application in the Deproteinization of Shrimp Waste,and Evaluation in Laundry Commercial Detergents

Alkaline proteases from the viscera of the striped seabream (Lithognathus mormyrus) were extracted and characterized. Interestingly, the crude enzyme was active over a wide range of pH from 6.0 to 11.0, with an optimum pH at the range of 8.0–10.0. In addition, the crude protease was stable over a broad pH range (5.0–12.0). The optimum temperature for enzyme activity was 50 °C. The crude alkaline proteases showed stability towards various surfactants and bleach agents and compatibility with some commercial detergents. It was stable towards several organic solvents and retained more than 50% of its original activity after 30 days of incubation at 30 °C in the presence of 25% (v/v) dimethyl sulfoxide, N,N-dimethylformamide, diethyl ether, and hexane. The crude enzyme extract was also tested for shrimp waste deproteinization in the preparation of chitin. The protein removal with a ratio enzyme/substrate of 10 was about 79%.     

A Novel α-Amylase from Bacillus mojavensis A21: Purification and Biochemical Characterization

α-Amylase from Bacillus mojavensis A21 (BMA.2) was purified to homogeneity by ultrafiltration, Sephadex G-75 gel filtration and Sepharose mono Q anion exchange chromatography, with a 15.3-fold increase in specific activity and 11% recovery. The molecular weight of the BMA.2 enzyme was estimated to be 58 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration. The optimum temperature and pH were 80?°C and 6.5, respectively. BMA.2 belonged to the EDTA-sensitive α-amylase, but its activity was not stimulated by the presence of Ca²⁺ ions. The major end-products of starch hydrolysis were maltohexaose, maltopentaose and maltotriose. The N-terminal amino acid sequence of the first ten amino acids of the purified α-amylase was ASVNGTLMQY. Compared to sequences of other amylases, the ten amino acid sequence contains Val at position 3, while amylases from Bacillus licheniformis NH1 and Bacillus sp. SG-1 have Leu and Thr at position 3, respectively.     

Fibrinolytic Serine Protease Isolation from <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis> An6 Grown on <Emphasis Type="Italic">Mirabilis jalapa</Emphasis> Tuber Powders

In this study, Mirabilis jalapa tuber powder (MJTP) was used as a new complex organic substrate for the growth and production of fibrinolytic enzymes by a newly isolated Bacillus amyloliquefaciens An6. Maximum protease activity (1,057 U/ml) with casein as a substrate was obtained when the strain was grown in medium containing (grams per liter) MJTP 30, yeast extract 6, CaCl₂ 1, K₂HPO₄ 0.1, and K₂HPO₄ 0.1. The strain was also found to grow and produce extracellular proteases in a medium containing only MJTP, indicating that it can obtain its carbon, nitrogen, and salts requirements directly from MJTP. The B. amyloliquefaciens An6 fibrinase (BAF1) was partially purified, and fibrinolytic activity was assayed in a test tube with an artificial fibrin clot. The molecular weight of the partially purified BAF1 fibrinolytic protease was estimated to be 30 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration. The optimum temperature and pH for the caseinolytic activity were 60 °C and 9.0, respectively. The enzyme was highly stable from pH 6.0 to 11.0 and retained 62% of its initial activity after 1 h incubation at 50 °C. However, the enzyme was inactivated at higher temperatures. The activity of the enzyme was totally lost in the presence of phenylmethylsulfonyl fluoride, suggesting that BAF1 is a serine protease.     

Methods for the numerical solution of the Benjamin‐Bona‐Mahony‐Burgers equation

L^∞‐error estimates for finite element for Galerkin solutions for the Benjamin‐Bona‐Mahony‐Burgers (BBMB) equation are considered. A priori bound and the semidiscrete Galerkin scheme are studied using appropriate projections. For fully discrete Galerkin schemes, we consider the backward Euler method and analyze the corresponding error estimates. For a second order accuracy in time, we propose a three‐level backward method. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008     

Mass spectrometry as a tool for the selective profiling of destruxins; their first identification in Lecanicillium longisporum

Mass spectrometry was applied to the identification of the destruxins (dtxs), cyclic peptides that are commonly produced by the fungal insect‐pathogen, Metarhizium anisopliae. The aim of the study was to optimise a methodology in order to firstly determine whether these compounds were present in other species and to determine the effect of differing growth conditions upon the dtx content detected. Matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐ToF‐MS) was initially used to analyse the dtxs, but limitations were indicated. Nano‐scale high‐performance liquid chromatography/electrospray ionisation mass spectrometry (HPLC/ESI‐MS) and automated ‘data‐dependent’ tandem mass spectrometric (MS/MS) analysis were also applied, utilising characteristic neutral losses during fragmentation to confirm the presence of the dtxs. This latter approach distinguished the dtx E and B isoforms by retention time and diagnostic neutral losses during fragmentation allowing extraction of the destruxin data from a complex dataset. This process revealed the presence of a number of dtxs in the fungal species Lecanicillium longisporum, a species previously not known to produce dtxs, and dtx production in this species was shown to be significantly higher in aerated cultures compared with still cultures. Copyright © 2009 John Wiley & Sons, Ltd.     

Diagnosis of deactivation sources for vanadium catalysts used in SO2 oxidation reaction and optimization of vanadium extraction from deactivated catalysts

Physico-chemical analysis (X-ray, FTIR) and/or methanol oxidation reaction test were performed on fresh and deactivated vanadium catalysts used in H₂SO₄ manufacturing. It allowed the diagnosis of catalyst deactivation sources, as well as the processes of regenerating and recycling the worn out catalyst in converter. One of these processes is hydrometallurgical method. It consists in treating the deactivated catalyst with alkaline or acidic reagents and forming vanadate solution. A simple and non-costly operation of chemical attack permits the extraction of vanadium from silica in deactivated catalyst. The extracted vanadium can be used for the confection of regenerated catalysts or metallic tools. After optimization, this method can be used for industrial application.     

Gamma-radiation induced decolorization and degradation on aqueous solutions of Indigo Carmine dye

Cesium uptake by natural zeolite clinoptilolite from Bulgaria was studied using batch technique and model solutions. The optimal conditions of interaction were determined. The pseudo-second-order rate model better describes the kinetic data obtained at different concentrations. The intraparticle diffusion and the surface diffusion models were tested to identify the rate-controlling step. The sites in the structure of clinoptilolite that are preferable for exchange were studied by application of Rietveld structural approach and the sequence of site occupation by cesium was followed. The Langmuir isotherm model provides a good fit of the equilibrium experimental data. The thermodynamic parameters for the system were calculated.