Simple and rapid detection of calcium peroxide in flour based on methanobactin peroxidase-like activity.

Calcium peroxide is forbidden to be added to flour as brightener in many countries. A rapid and sensitive spectrophotometric method for the detection of calcium peroxide in flour was proposed. Methanobactin (Mb), a copper-binding small peptide of methanotrophs with excellent peroxidase-like activity, has been successfully applied for HO-mediated co-oxidation between phenol and 4-aminoantipyrine to give a colored product that can be detected at 505 nm.

Hybridization of Particulate Methane Monooxygenase by Methanobactin-Modified AuNPs.

Particulate methane monooxygenase (pMMO) is a characteristic membrane-bound metalloenzyme of methane-oxidizing bacteria that can catalyze the bioconversion of methane to methanol. However, in order to achieve pMMO-based continuous methane-to-methanol bioconversion, the problems of reducing power in vitro regeneration and pMMO stability need to be overcome. Methanobactin (Mb) is a small copper-chelating molecule that functions not only as electron carrier for pMMO catalysis and pMMO protector against oxygen radicals, but also as an agent for copper acquisition and uptake.

Novozym435-Gold Nanoparticles Biohybrids as an Efficient Catalyst for Synthesis of Ferulic Acid Starch Ester.

Novozym435-gold nanoparticles biohybrids (NAuB) were synthesized and characterized in this work, with subsequent investigations on their catalytic activities and stability in compared with the initial form of Novozym435. This is a new way to modify immobilized enzyme by physical means. The elemental analysis of NAuB showed that Au was also the major element except C and O.

Preparation of Electrode Modified with Methanobactin Functionalized Gold Nanoparticle and Mimic Superoxide Dismutase Activity.

Using a mixed self-assembly method, this research utilized modified Mb-functionalized gold nanoparticles (Mb-AuNPs-MPA) on the gold electrode surface to prepare a biosensor which was applied to detect superoxide anion-free electron mediators. Together with the study on the performance of the sensor, the characteristics of modified nanoclusters were investigated by UV-Vis and FTIR and the electrochemical characteristics of the electrode surface were investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. It was demonstrated that the charge transfer resistance (Rct) of the modified electrode (Mb-MPA-AuNPs/Au) was 7862 Ω, the exchange current density () was 32.

Cu-induced assembly of methanobactin-modified gold nanoparticles and its peroxidase mimic activity.

Methanobactin (Mb) is a small copper-chelating molecule that functions as an agent for copper acquisition, uptake and copper-containing methane monooxygenase catalysis in methane-oxidising bacteria. The UV-visible spectral and fluorescence spectral suggested that Mb/Cu coordination complex as a monomer (Mb-Cu), dimmer (Mb-Cu) and tetramer (Mb-Cu) could be obtained at different ratios of Mb to Cu (II). The kinetics of the oxidation of hydroquinone with hydrogen peroxide catalysed by the different Mb/Cu coordination complex were investigated.

Methanobactin-mediated synthesis of bimetallic Au-Pd/AlO toward an efficient catalyst for glucose oxidation.

A green bioreductive approach with methanobactin was adopted to fabricate bimetallic Au-Pd/AlO catalysts for solvent-free oxidation of glucose to gluconic acid with HO at atmospheric pressure. The catalyst was characterised by diffuse reflectance UV-vis spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction techniques to understand synergistic interactions between Au and Pd. Effects of Au to Pd molar ratio on the catalytic activity of Au-Pd/AlO were investigated.

Biosynthesis of (S)-naproxen starch ester by Carica papaya lipase in intermittent opening reaction mode.

Inorder to brought S-naproxen into small intestine, an optically pure (S)-naproxen starch ester was produced by lipase through enantio-selective trans-esterification of racemic naproxen methyl ester with pretreatment starch in solvent system. With carefully selection of the reaction medium (isooctane), lipase (Carica Papaya Lipase, CPL) and the reaction mode (intermittent opening), a high conversion rate (48.6%) and enantiomeric excess of product (99.

Synthesis of L-Ascorbyl Flurbiprofenate by Lipase-Catalyzed Esterification and Transesterification Reactions.

The synthesis of L-ascorbyl flurbiprofenate was achieved by esterification and transesterification in nonaqueous organic medium with Novozym 435 lipase as biocatalyst. The conversion was greatly influenced by the kinds of organic solvents, speed of agitation, catalyst loading amount, reaction time, and molar ratio of acyl donor to L-ascorbic acid. A series of solvents were investigated, and tert-butanol was found to be the most suitable from the standpoint of the substrate solubility and the conversion for both the esterification and transesterification.

Study of clinical practical model of urinary system injury.

Background: In order to improve the clinical treatment level of urinary system injury, it is necessary to build up an animal model of urinary system wound, which is not only analogous to real clinical practice, but also simple and practical.

Methods: We have developed the third generation of firearm fragment wound generator based on the first and the second producer. The best explosive charge of the blank cartridge was selected by gradient powder loading experiments.

Colorimetric detection of melamine based on methanobactin-mediated synthesis of gold nanoparticles.

A simple and rapid field-portable colorimetric method for the detection of melamine in liquid milk was reported. Methanobactin (Mb) could reduce Au (III) to Au (0) and mediate the synthesis of gold nanoparticles (Au-NPs). Upon the addition of melamine, melamine interacted with oxazolone ring of Mb, which interrupted the formation of Au-NPs.

Methanobactin-mediated synthesis of gold nanoparticles supported over Al2O3 toward an efficient catalyst for glucose oxidation.

Methanobactin (Mb) is a copper-binding peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and reduce Au(III) to Au(0). In this paper, Au/Al2O3 catalysts prepared by a novel incipient wetness-Mb-mediated bioreduction method were used for glucose oxidation.

Methanobactin-mediated one-step synthesis of gold nanoparticles.

Preparation of gold nanoparticles with a narrow size distribution has enormous importance in nanotechnology. Methanobactin (Mb) is a copper-binding small peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and catalytically reduce Au (III) to Au (0).

Biosysthesis of corn starch palmitate by lipase Novozym 435.

Esterification of starch was carried out to expand the usefulness of starch for a myriad of industrial applications. Lipase B from Candida antarctica, immobilized on macroporous acrylic resin (Novozym 435), was used for starch esterification in two reaction systems: micro-solvent system and solvent-free system. The esterification of corn starch with palmitic acid in the solvent-free system and micro-solvent system gave a degree of substitution (DS) of 1.

Methanol production from CO(2) by resting cells of the methanotrophic bacterium Methylosinus trichosporium IMV 3011.

Methanol production from carbon dioxide was successfully achieved using resting cells of Methylosinus trichosporium IMV 3011 as biocatalysts. Carbon dioxide was reduced to methanol and extracellular methanol accumulation has been found in the carbon dioxide incubations. However, resting cells of methanotrophs have a finite or intrinsic methanol production capacity due to a limiting supply of intracellular reducing equivalent.

Environmentally friendly, efficient resolution of racemic secondary alcohols by lipase-catalyzed enantioselective transesterification in ionic liquids in the presence of organic bases.

The lipase-catalyzed enantioselective transesterification of racemic secondary alcohols was studied using vinyl acetate as acyl donor in two imidazolium-based ionic liquids vs. hexane (Scheme), both in the absence and presence of catalytic amounts of organic bases such as triethylamine (Et(3)N) or pyridine. The organic bases generally enhanced both the rate and enantioselectivity of the reaction.

[Methane monooxygenases hydroxylase from a type II methanotroph: purification and physical-chemical properties].

Methanotrophs can catalyze hydroxylate of methane and some hydrocarbon. Which play an important role in mitigating global warming and have also potential significance for industrial applications or bioremediation. A high activity of hydroxylase, a crucial component in sMMO, from Methylosinus trichosporium IMV 3011 has been purified to homologues by using chromatographic techniques.

Fine separation and characterization of Candida rugosa lipase isoenzymes.

Commercial Candida rugosa lipase has been separated into two distinct fractions (CRLA and CRLB) by anion-exchange chromatography. As analyzed on SDS-polyacrylamide gel electrophoresis, CRLA and CRLB are homogenous. At high ionic strength, CRLA and CRLB have similar hydrophobicity and UV spectra, suggesting that the open extent of the large hydrophobic pockets of CRLA and CRLB may be similar.

Particulate methane monooxygenase from Methylosinus trichosporium is a copper-containing enzyme.

Particulate methane monooxygenase (pMMO) has been exfoliated and isolated from membranes of the Methylosinus trichosporium IMV 3011. It appears that the stability of pMMO in the exfoliation process is increased with increasing copper concentration in the growth medium, but extensive intracytoplasmic membrane formed under higher copper concentration may inhibit the exfoliation of active pMMO from membrane. The highest total activity of purified pMMO is obtained with an initial concentration of 6 microM Cu in the growth medium.

[Continuous biosynthesis of epoxypropane in a methanotrophic attached-films reactor].

Using a fluidized bed as immobilization system, mixed culture methanotrophic attached-films were developed on diatomite particles. The Methane Monooxygenase (MMO) activity was found to increase obviously as soon as the lag phase ended. Greater than 90% of the MMO activity in the bed was attached.