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81.
Over recent years, there has been a growing interest in the use of cellulose materials in bioprocessing technologies. Bacterial cellulose which is the pure cellulose has unique physical properties which differ from those of plant cellulose and has therefore attracted attention as a new functional material. The applications of bacterial cellulose rarely use the pellet type but it has potential in enzyme immobilization since pellet form is usually used in this field. In this research, Glucoamylase which is widely used in the food industry was immobilized on bacterial cellulose beads after testing using various activation procedures. The results showed that the epoxy method with glutaraldehyde coupling was the best method. After comparison of the different types of bacterial cellulose beads for glucoamylase immobilization, the wet bacterial cellulose beads of the smallest size (0.5–1.5 mm) were the best support. The immobilization of enzyme enhances its stability against changes in the pH value and temperature especially in the lower temperature region. The relative activity of the immobilized glucoamylase was still above 77% at pH 2.0 and it was the highest value in the literature. The relative activities were more than 68% in the lower temperature region even at 20 °C. Thus, bacterial cellulose beads are a practical potential support for the preparation of immobilized enzymes in industrial applications. 相似文献
82.
Song Su-Han Kim Teak-Bum Oh Hoon-Il Oh Deok-Kun 《World journal of microbiology & biotechnology》2003,19(7):727-731
High concentrations of ammonium and sodium ions inhibited Bifidobacterium longum growth more than a high calcium ion concentration. The optimal pH for B. longum growth was determined to be 5.0 due to the lower accumulation of ammonium ion. To reduce the accumulation of ammonium ion and obtain an enhanced growth of B. longum, the pH of the culture containing immobilized calcium carbonate beads was controlled to 5.0 with ammonia water. The concentrations of ammonium, sodium, and calcium ions in the culture were maintained at the desired level. The maximum cell mass increased to 16.8 g/l, 1.23 times higher than cultures without calcium carbonate beads. The number of viable cells in the culture increased to 5.0 × 1010, 1.67 times more than cultures without calcium carbonate beads. 相似文献
83.
Polymer-coated magnetic beads have become widely used in biological applications because of their facile recovery and easily
modifiable surface. Herein, we report the application of magnetic beads to in vitro refolding of B. cepacia lipase. Magnetic particles (Fe3O4) prepared by co-precipitation of Fe2+ and Fe3+ ions under basic conditions were subsequently coated with carboxylic acid-containing polystyrene by emulsion polymerization.
The polymer-coated magnetic beads were then conjugated with molecular chaperone proteins to assist with refolding. The chaperone-conjugated
magnetic beads efficiently refolded B. cepacia lipase and were easily reused. The beads showed comparable refolding activity to the soluble chaperone, and retained more
than 95% of their refolding activity after five cycles of refolding B. cepacia lipase. 相似文献
84.
85.
zlem Alptekin S. Seyhan Tükel Deniz Yldrm Dilek Alagz 《Journal of Molecular Catalysis .B, Enzymatic》2009,58(1-4):124-131
Bovine liver catalase was covalently immobilized onto controlled pore glass (CPG) beads modified with 3-aminopropyltriethoxysilane (3-APTES) followed by treatment with glutaraldehyde. Coupling of catalase onto CPG was optimized to improve the efficiency of the overall immobilization procedure. The optimum coupling conditions: pore diameter of CPG, pH, buffer concentration, temperature, coupling time and initial catalase amount per grams of carrier were determined as 70 nm, 6.0, 75 mM, 5 °C, 7 h and 6 mg catalase, respectively. Catalytic efficiencies (kcat/Km) and thermal inactivation rate constants (ki) of ICPG1 were determined and compared with that of free catalase. Suitability of ICPG1 was also investigated by using it in batch and plug-flow type reactors. When the remaining activity of ICPG1 retained was about 50% of its initial activity the highest total productivity of ICPG1 was determined as 7.6 × 106 U g immobilized catalase−1 in plug-flow type reactor. However, the highest total productivity of ICPG1 was 6.2 × 105 U g immobilized catalase−1 in batch type reactor. ICPG1 may have great potentials as biocatalyst for the application in decomposition of hydrogen peroxide in plug-flow type reactor. 相似文献
86.
This article describes the employment of a novel p-phenol derivative, 4-(1,2,4-triazol-1-yl)phenol (TRP), as a highly potent signal enhancer of the luminol-hydrogen peroxide (H2O2)-horseradish peroxidase (HRP) chemiluminescence (CL) system. The CL reaction conditions were optimized, and the enhancement characteristics of TRP were compared with those of p-iodophenol (PIP). TRP produced a strong enhancement of the CL with the effect of prolonging the light emission. The developed system was then applied to the determination of H2O2 with immobilized HRP using magnetic beads as a solid support. The linear range for H2O2 was 2.0 × 10−6 to 1.0 × 10−3 M. The detection limit for H2O2 was 2.0 × 10−6 M. The proposed sensor was applied successfully to the determination of H2O2 in rainwater. 相似文献
87.
Andrew J.Parsons Ifty Ahmed Papia Haque Ben Fitzpatrick Muhammad I.K.Niazi Gavin S.Walker Chris D.Rudd 《仿生工程学报(英文版)》2009,6(4):318-323
We investigate high-modulus degradable materials intended to replace metals in biomedical applications.These are typicallycomposites comprising a polylactide(PLA)matrix reinforced with phosphate glass fibres,which provide reinforcementsimilar to E-glass but are entirely degradable in water to produce,principally,calcium phosphate.We have made compositesusing a variety of fibre architectures,from non-woven random mats to unidirectional fibre tapes.Flexural properties in theregion of 30 GPa modulus and 350 MPa strength have been achieved-directly comparable to quoted values for human corticalbone.In collaboration with other groups we have begun to consider the development of foamed systems with structures mimickingcancellous bone and this has shown significant promise.The fibres in these foamed structures provide improved creepresistance and reinforcement of the pore walls.To date the materials have exhibited excellent cellular responses in vitro andfurther studies are due to include consideration of the surface character of the materials and the influence of this on cell interaction,both with the composites and the glass fibres themselves,which show promise as a standalone porous scaffold. 相似文献
88.
Xin Zhan Hai-Yan Hu Cai-Huan Ke Song-Nian Hu De-Xiang Wang Fei Chen 《Conservation Genetics》2009,10(4):1185-1187
Eleven novel microsatellite markers were isolated from small abalone, Haliotis diversicolor Reeve. These loci were tested on 22 individuals from two different geographic populations. We identified a total of 162 alleles
from the 11 microsatellite loci. All of the loci were highly polymorphic. Polymorphism information content (PIC) is ranging
from 0.7276 to 0.9163. Observed and expected heterozygosities ranged from 0.2727 to 1.0000 and from 0.7738 to 0.9429, respectively.
Three loci deviated significantly from Hardy–Weinberg equilibrium. No pairs of loci displayed linkage disequilibrium. These
polymorphic markers will be used to analyze population structure, genetic diversity and construct a genetic linkage map.
Xin Zhan and Hai-Yan Hu contribute equally to this study. 相似文献
89.
90.
The optimization of DNA hybridization for genotyping assays is a complex experimental problem that depends on multiple factors such as assay formats, fluorescent probes, target sequence, experimental conditions, and data analysis. Quantum dot-doped particle bioconjugates have been previously described as fluorescent probes to identify single nucleotide polymorphisms even though this advanced fluorescent material has shown structural instability in aqueous environments. To achieve the optimization of DNA hybridization to quantum dot-doped particle bioconjugates in suspension while maximizing the stability of the probe materials, a nonsequential optimization approach was evaluated. The design of experiment with response surface methodology and multiple optimization response was used to maximize the recovery of fluorescent probe at the end of the assay simultaneously with the optimization of target–probe binding. Hybridization efficiency was evaluated by the attachment of fluorescent oligonucleotides to the fluorescent probe through continuous flow cytometry detection. Optimal conditions were predicted with the model and tested for the identification of single nucleotide polymorphisms. The design of experiment has been shown to significantly improve biochemistry and biotechnology optimization processes. Here we demonstrate the potential of this statistical approach to facilitate the optimization of experimental protocol that involves material science and molecular biology. 相似文献