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The present work shows the application of nickel- and magnesium-crosslinked gellan microspheres in ionic and affinity capture strategies to directly extract hSCOMT from the complex Komagataella pastoris lysate through a simple batch method. Both formulations present similar morphology, but nickel–crosslinked microspheres present higher crosslinker content and smaller diameters. Four different capture strategies were established, by manipulating the ionic strength, pH, temperature and competing agents' presence. The most promising results for hSCOMT capture and clarification were obtained employing an ionic strategy with nickel-crosslinked microspheres and an affinity strategy with magnesium-crosslinked microspheres at 4 °C. The bioactivity results (200%) and purification degree (70%) of hSCOMT captured by the ionic strategy were more satisfactory probably due to the soft ionic conditions used (100 mM NaCl). For the first time, the gellan polysaccharide versatility was demonstrated in the microsphere application for the direct capture of hSCOMT from a complex lysate, simplifying isolation biotechnological procedures.

In this work, a study has been carried out to investigate the resistance of commercial poly(vinylidene fluoride) PVDF in its β phase to UV radiation using a xenon lamp. The radiation was applied for 10 weeks and, during this time, the variation in the chemical structure, crystallinity, dielectric and piezoelectric response was monitored. The results show that PVDF has a very good resistance against the effect of UV radiation as no significant changes were detected either at a molecular level or in the electro-active response. It can be concluded that PVDF shows high stability towards photodegradation and can be used for outdoor applications without loss in performance.

In this work, commercial poly(vinylidene fluoride) PVDF, in its β phase was analysed before and after the samples were exposed to UV radiation using a xenon lamp, for ten weeks. Changes in chemical structures, crystallinity, dielectric and piezoelectric response were investigated. From the present study it can be concluded that PVDF shows high stability towards photodegradation and can be used for outdoor applications without interference in its performance.

Poly(vinylidene fluoride), PVDF, in its β-phase is an electroactive polymer with many technological applications. There are two main ways to prepare this polymer in its electroactive β-phase: by high temperature stretching from the α-phase and directly from solution. In this paper, the influence of the processing methods in the thermal stability of the samples was studied by UV–VIS spectroscopy and thermogravimetric analysis. The number of chain defects was measured by 1 H NMR. The results obtained were compared to a commercial β-PVDF sample. The number of head to head defects in the different samples is found to be between 6% and 9%. The onset temperature for thermal degradation and the average activation energy (∼76.5 kJ mol −1 ) of the process are approximately equal for the α-phase sample and the β-phase obtained from it. Larger values of the onset temperature and average activation energy (∼100 kJ mol −1 ) are found for the β-phase sample directly obtained from the solution and for the commercial β-phase sample. The thermal degradation of the samples occurs in two steps, independently of the phase of the sample, the degree of crystallinity and the processing method.

The unfolding of cutinase at pH 4.5 was induced by increasing the temperature and guanidine hydrochloride concentration in the presence of potassium chloride, trehalose, and mannosylglycerate potassium salt. Protein thermal unfolding approached a two-state process, since the unfolding transitions were coincident within experimental error when assessed by near-ultraviolet (UV) difference, tryptophyl, and 8-anilino-1-naphthalene sulfonic acid (ANS) fluorescence spectroscopy. Trehalose at 0.5 M increased the temperature at which 50% of cutinase is unfolded by 3 degrees C. Unfolding induced by guanidine hydrochloride is clearly a non-two-state process. The presence of a stable intermediate was detected because unfolding assessed by near-UV difference spectroscopy occurs earlier than unfolding assessed by tryptophyl fluorescence. The intermediate is molten globule in character: the ANS fluorescence is higher than in the presence of the folded or unfolded state, showing native-like secondary structure and losing many tertiary interactions of the folded state, i.e., those surrounding the tyrosyl microenvironment. The stabilization effect of trehalose and mannosylglycerate was quantified by fitting the unfolding transitions to a model proposed by Staniforth et al. (Biochemistry 1993;32:3842-3851). This model takes into consideration the increase in solvation energies of the amino acid side-chains as the denaturant concentration was increased and the fraction of amino acid side-chains that become exposed in the unfolded structure of cutinase. Trehalose and mannosylglycerate stabilize the folded state relative to the intermediate by 1.4-1.6 and 1.6 kcal/mol and the intermediate relative to the unfolded state by 1.0 and 1.5 kcal/mol, respectively.

The effects of aqueous surfactant solutions on the kinetics and stability of cutinase from Fusarium solani pisi were studied. The surfactant sodium bis[2-ethylhexyl]ester sulfosuccinic acid (AOT) acts as a pseudo-competitive inhibitor within a limited concentration range relative to the hydrolysis of short-chain p-nitrophenyl esters. For higher concentrations a hyperbolic mixed inhibition takes place. A pseudo-activation of hydrolysis in presence of AOT and hexadecyltrimethyl-ammonium bromide (CTAB) was observed. CTAB has similar effects on kinetics of cutinase. Cutinase revealed to be stable in CTAB solutions, with activity retention as high as 80%. AOT has a deleterious effect on the enzyme in the time course, resulting in acute loss of activity possibly related with unfolding of the protein structure. A relation between deactivation rate constants and AOT/cutinase concentration ratios is suggested. The presence of the linear alcohol, 1-hexanol, was included in these solutions, in the attempt to interpret the deactivation of cutinase when encapsulated in reversed micelle systems in the absence of this co-surfactant.

Recombinant cutinase from Fusarium solani pisi was covalently attached to dextran and two derivatized silica supports, Biosil-NH2 and Biosil-Dextran-NH2. Kinetic parameters were determined for all three systems as well as for soluble cutinase. Long-term stability in aqueous media was studied; dextran may have a stabilizing role not only due to the covalent links involved but also in the same way as other polyhydroxides in aqueous media. Differential scanning calorimetry analysis suggests an enhancement of conformational stability of the immobilized forms. http://www.sciencedirect.com/science/article/B6TG1-4165DGC-9/1/b62e6c1431e1ea508958b86755959198

Adsorption isotherms of the pure vapours and of liquid mixtures of water and methanol on charcoal cloth at 293K have been determined. The surface excess isotherms show that methanol is always the preferentially adsorbed component over the whole composition range. The isotherms exhibit an unusual feature with a secondary maximum at high mole fractions of methanol. In order to explain this behaviour charcoal cloth was studied before and after modification of the surface chemical structure. Evidence was found that as the polarity decreases the surface excess increases and the secondary maximum becomes less pronounced.