Hemoglobin-biocatalyzed synthesis of conducting molecular complex of polyaniline and lignosulfonate

A new biocatalyst route for the synthesis of a conducting polyaniline （PANI）/ lignosulfonate （LGS） complex was presented.Four different catalysts such as hemoglobin （Hb）,5,10,15,20-tetrakis （meso-hydroxyphenyl） porphyrin,iron （II） tetrasulfophthalocyanine and ferric chloride were used to polymerize aniline in the presence of a natural polyelectrolytes template LGS.The experimental results show that Hb is an effective catalyst in this case and the synthesis is simple,and the conditions are mild in that the polymerization may be carried out in lower pH （1.0-4.0） buffered solution and optimal pH of 2.0.Varying concentrations of aniline,LGS and H2O2 in feed the favorable conditions for the production of PANI were determined.UV-vis absorption,FTIR,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analyses confirm the formation of thermally stable and electroactive PANI.     

Construction of a Artificial Glutathione Peroxidase with Temperature‐Dependent Activity Based on a Supramolecular Graft Copolymer

A supramolecular artificial glutathione peroxidase (PNIPAM‐CD‐g‐Te) was prepared based on a supramolecular graft copolymer. PNIPAM‐CD‐g‐Te was constructed by supramolecular host–guest self‐assembly. Significantly, PNIPAM‐CD‐g‐Te displayed noticeable temperature‐dependent catalytic activity and typical saturation kinetics behavior. It was also proved that the change in the self‐assembled structure of PNIPAM‐CD‐g‐Te during the temperature‐dependent process played a significant role in the temperature‐dependent catalytic behavior. The construction of PNIPAM‐CD‐g‐Te based on supramolecular graft copolymer endows artificial GPx with temperature‐dependent catalytic ability, enriched catalytic centers, and homogeneously distributed catalytic centers. This work bodes well for the development of other biologically related host–guest supramolecular biomaterials.     

Hemoglobin-biocatalyzed Synthesis of Conducting Molecular Complex of Polyaniline and Lignosuifonate

A new biocatalyst route for the synthesis of a conducting polyaniline (PANI)/lignosulfonate (LGS) complex was presented.Four different catalysts such as hemoglobin (Hb),5,10,15,20-tetrakis (meso-hydroxyphenyl) porphyrin,iron (Ⅱ) tetrasulfophthalocyanine and ferric chloride were used to polymerize aniline in the presence of a natural polyelectrolytes template LGS.The experimental results show that Hb is an effective catalyst in this case and the synthesis is simple,and the conditions are mild in that the polymerization may be carried out in lower pH (1.0-4.0) buffered solution and optimal pH of 2.0.Varying concentrations of aniline,LGS and H2O2 in feed the favorable conditions for the production of PANI were determined.UV-vis absorption,FFIR,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analyses confirm the formation of thermally stable and electroactive PANI.     

手性化合物与生物催化剂

手性化合物作为医药、农药、香料、功能性材料的前体、中间体或终产物在精细化工产品的生产中占有极其重要的地位。手性化合物的生物合成与拆分是利用统称为生物催化剂的酶促反应或微生物转化的高度底物、立体、位点、区域选择性,将化学合成的前体、潜手性化合物或外消旋衍生物转化成单一光学活性产物。     

Design of immobilised glucoamylase reactors using a simple kinetic model for the hydrolysis of starch

A comparative study is reported of the three main types of continuous reactors, continuous feed stirred tank reactor (CFSTR), packed bed reactor (PBR) and fluidised bed reactor (FBR), for the conversion at 50°C of a 30% (w/w) corn syrup 40 DE using glucoamylase (exo-1,4-D-glucosidase, EC 3.2.1.3) immobilised on carbonyl derivatives of titanium(IV)-activated porous silica by a method developed previously.^1–3 The hydrolysis of starch in these reactors is described by a simple kinetic model⁴ which involves the intrinsic kinetic constants as well as mass transfer and dispersion effects, and allows the computation of enzyme activity values under continuous operation. FBR appears to be more effective for the hydrolysis of starch. This reactor also confers a better operational stability (t_1/2=775h) on the immobilised enzyme than the other immobilised glucoamylase reactors (PBR, t_1/2=629h; CFSTR, t_1/2=239h).     

A kinetic model for the decrease in lipase activity of rhizopus arrhizus and penicillium cyclopium mycelia in organic media

The decrease in Lipase activity of Rhizopus arrhizus and Penicillium cyclopium mycelia (RAM and PCM) were studied in alkanes, ethers and chloroalkanes. The two biocatalysts showed similar behaviour in organic media, although RAM was slightly more stable. The kinetic model obtained indicated that the decrease in activity followed a succession of two first-order reactions. Both RAM and PCM were more stable in hydrophobic solvents. These two mycelia were used to synthesize N-octyl-myristylamide; yield of the amide was linked in a linear relationship to the average activity of biocatalyst in the solvent employed.     

Modelling of the Hydrolysis of Benzylpenicillin to 6-Aminopenicillanic Acid and Phenyl Acetic Acid by an Immobilised Penicillin Amidase in a Small Pilot Plant Batch Recirculated Reactor

This paper deals with the modelling of the hydrolysis of benzylpenicillin to 6-aminopenicillanic acid (6-APA) and phenyl acetic acid (PAA) in a small pilot plant batch recirculated reactor by an immobilised penicillin amidase preparation. By using the following linearised form for an integrated Michaelis-Menten equation Et/V₀X=α+β| In (1-X)/X| where α and β are reaction kinetic parameters, good correlations are obtained of α and β with linear velocity across the reactor, substrate concentration and temperature of operation. A process to determine α and β from initial velocity measurements is outlined. The applicability of the above equation to published data is also analysed.     

Novel thin‐film reactor for photocatalytic degradation of pesticides in an aqueous solution

A thin‐film reactor was fabricated with immobilised TiO₂ and this reactor was used for photocatalytic mineralisation of common pesticides, 2,4‐dichlorophenoxyacetic acid (DPA) and monocrotophos (MCP), and their commercially formulated products in an aqueous solution. Zeolites HY and Hβ with different physico‐chemical properties were chosen as support material. The supported TiO₂ was used for the degradation and mineralisation studies. TiO₂/zeolite‐supported photocatalyst showed enhanced degradation efficiency compared with bare TiO₂ for both DPA and MCP. Formulated pesticides were mineralised at shorter irradiation times than technical grade pesticides. The results clearly demonstrated that the good adsorption capacity of the support, and the effective light utilisation by TiO₂, improved the photocatalytic activity of supported TiO₂. Reusability studies have also shown the stability of supported photocatalysts. Copyright © 2004 Society of Chemical Industry     

Immobilised cellulolytic and hemicellulolytic enzymes from Macrophomina phaseolina

Cellulolytic enzymes from Macrophomina phaseolina were immobilised in acrylamide polymer. The immobilised enzyme preparation showed activity towards filter paper and cotton. However, the degree of hydrolysis of highly organised cellulose, particularly cotton, appears to be low in comparison with that of soluble substrate. The kinetic studies of immobilised enzymes indicated the presence of diffusional limitations by the increase in V_max as the particle size decreased. The operational studies suggested that the immobilised enzymes retained the original activities up to 25–29 times in the reuse cycle.     

人工合成膜——生物催化剂固定化的新载体

合成膜在生化工程中最新应用是作为生物催化剂固定化的新载体。人工膜用于固定化生物催化剂近年来引起了人们的极大关注并获得了广泛地研究。不同的膜体系及运行方式与生物催化剂相结合构成了多种膜生化反应器。本文介绍并综述了膜固定化生物催化剂的原理、方法分类和应用。