Abstract:
:In this work, novel conductive composite nanofiber mesh possessing reactive groups was electrospun from solutions containing poly(acrylonitrile-co-acrylic acid) (PANCAA) and multi-walled carbon nanotubes (MWCNTs) for redoxase immobilization, assuming that the incorporated MWCNTs could behave as electrons transferor during enzyme catalysis. The covalent immobilization of catalase from bovine liver on the neat PANCAA nanofiber mesh or the composite one was processed in the presence of EDC/NHS. Results indicated that both the amount and activity retention of bound catalase on the composite nanofiber mesh were higher than those on the neat PANCAA nanofiber mesh, and the activity increased up to 42%. Kinetic parameters, K(m) and V(max), for the catalases immobilized on the composite nanofiber mesh were lower and higher than those on the neat one, respectively. This enhanced activity might be ascribed to either promoted electron transfer through charge-transfer complexes and the pi system of carbon nanotubes or rendered biocompatibility by modified MWCNTs. Furthermore, the immobilized catalases revealed much more stability after MWCNTs were incorporated into the polymer nanofiber mesh. However, there was no significant difference in optimum pH value and temperature, thermal stability and operational stability between these two immobilized preparations, while the two ones appeared more advantageous than the free in these properties. The effect of MWCNTs incorporation on another redox enzyme, peroxidase, was also studied and it was found that the activity increased by 68% in comparison of composite one with neat preparation.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Wang ZG,Ke BB,Xu ZKdoi
10.1002/bit.21280subject
Has Abstractpub_date
2007-07-01 00:00:00pages
708-20issue
4eissn
0006-3592issn
1097-0290journal_volume
97pub_type
杂志文章abstract::Gene transcription is regulated by transcription factors that can bind to specific regions on DNA. Antigene oligonucleotides (oligos) can bind to specific regions on DNA and form a triplex with the double-stranded DNA. The triplex can competitively inhibit the binding of transcription factors and, as a result, transcr...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/1097-0290(20001120)70:4<467::aid-bit13>3.0
更新日期:2000-11-20 00:00:00
abstract::Maintenance of high cell viability was the main characteristic of our new strains of thermotolerant Saccharomyces. Total sugar conversion to ethanol was observed for sugarcane juice fermentation at 38-40 degrees C in less than 10 h and without continuous aeration of the culture. Invertase activity differed among the s...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260370606
更新日期:1991-03-15 00:00:00
abstract::A model for radial flow mammalian cell culture has been developed. Two situations, one with permeable hollow fibers and the other with a porous matrix in the annulus, were considered. The hollow fibers were modeled as continuously distributed sinks. Numerical solutions are presented for the complete model as well as l...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260290602
更新日期:1987-04-01 00:00:00
abstract::The purpose of this article is to provide a few concrete examples of the potential to acceptably reduce the scope of validation and qualification testing based on scientific justification for the specific area of microbial fermentation. The key areas explored include: autoclave operational qualification (OQ) testing, ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1094
更新日期:2001-07-05 00:00:00
abstract::Studies have been conducted in a gas circulation type fermentor in order to characterize the ethanol fermentation of uncooked cassava starch with Rhizopus koji. Results showed that ethanol concentration reached 13-14% (v/v) in 4-day broth, and the maximum productivity of ethanol was 2.3 g ethanol/L broth h. This produ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260270823
更新日期:1985-08-01 00:00:00
abstract::We originally investigated the suitability of chitosan scaffolds loaded with bone morphogenetic protein 6 (BMP-6) in both stationary and dynamic conditions for cartilage tissue engineering. In the first part of the present study, ATDC5 murine chondrogenic cells were seeded in chitosan and BMP-6 loaded chitosan scaffol...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22426
更新日期:2009-10-15 00:00:00
abstract::The production of soluble microbial products (SMP) in anaerobic systems was evaluated using chemostat reactors. Results from steady-state and tracer experiments with (14)C-glucose and (14)C-acetate showed that significant amounts of SMP were produced during the acidogenesis of glucose, but that SMP did not accumulate ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260440904
更新日期:1994-11-05 00:00:00
abstract::The kinetics and mechanism of Fe(III) reduction to Fe(II) were studied in pure batch cultures of Pseudomonas sp. 200. The rate of iron reduction has been mechanistically related to aqueous phase iron speciation. In the absence of microbial activity the iron reduction rate was negligible. Initial rates of microbial iro...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260281110
更新日期:1986-11-01 00:00:00
abstract::For all bacteria, nearly every antimicrobial fails since a subpopulation of the bacteria enter a dormant state known as persistence, in which the antimicrobials are rendered ineffective due to the lack of metabolism. This tolerance to antibiotics makes microbial infections the leading cause of death worldwide and make...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25963
更新日期:2016-09-01 00:00:00
abstract::Extraction of intracellular protein from Escherichia coli is traditionally achieved by mechanical disruption. A chemical treatment that destroys the integrity of the bacterial cell wall and could provide an alternative technique is examined in this study. Treatment with a combination of the chelating agent ethylenedia...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0290(19970305)53:5<453::AID-BIT
更新日期:1997-03-05 00:00:00
abstract::The starting point for the present investigations was the finding that increasing influent concentrations from 10 to 380 mmol/L glucose decreased the attainable growth rate of an acidogenic population in continuous culture from 0.52 to 0.05 h(-1) To account for this phenomenon, a new kinetic model is developed that co...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260310714
更新日期:1988-05-01 00:00:00
abstract::An analysis of the radial flow cell is presented to show that the assumption of creeping laminar flow should be used cautiously. Simple models which account for the influence of fluid inertial forces over most of the width of the plate are reviewed. A modified Reynolds number is introduced which may be used to test th...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260270407
更新日期:1985-04-01 00:00:00
abstract::A detailed mechanistic model of enzymatic cellulose hydrolysis has been developed. The behavior of individual cellulase enzymes and parameters describing the cellulose surface properties are included. Results obtained for individual enzymes (T. reesei endoglucanase 2 and cellobiohydrolase I) and systems with both enzy...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22789
更新日期:2010-09-01 00:00:00
abstract::The thermophilic fungus Sporotrichum cellulophilum was immobilized with nonwoven materials for cellulase production. The cellulose powder concentration in the medium was an important factor controlling cellulase production. When the cellulose powder concentration in the nonwoven materials was more than 4%, cellulase p...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280814
更新日期:1986-08-01 00:00:00
abstract::An aeration tank/sedimentation tank system is considered for large variations of organic loading. In this case, it is important to take into account the variability of the characteristics describing the oxidation of activated sludge as well as its sedimentation. The minimum cost of the treatment system is also evaluat...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260241105
更新日期:1982-11-01 00:00:00
abstract::Protein phosphorylation is an important post-translational modification for intracellular signaling molecules, mostly found in serine and threonine residues. Tyrosine phosphorylations are very few events (less than 0.1% to phosphorylated serine/threonine residues), but capable of governing cell fate decisions involved...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25948
更新日期:2016-08-01 00:00:00
abstract::Immobilization of Streptomyces phaerochromogenes was studied by radiation-induced polymerization of 2-hydroxyethyl methacrylate at low temperatures. Radiation damage of the enzyme could be avoided by choosing irradiation at low temperatures. The enzymatic activity of immobilized cells increased remarkably with a decre...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260210412
更新日期:1979-04-01 00:00:00
abstract::The DeltaSf of one unit carbon formula weight of Escherichia coli K-12 cells, when grown on succinic acid, was calculated to be -80.13 J/deg. This value could then be used to calculate the entropy change accompanying the anabolism and metabolism of succinic acid to be 30.82 J/deg and 32.40 J/mol deg, respectively. The...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260410405
更新日期:1993-02-20 00:00:00
abstract::Exposure of Bacillus subtilis to a shear rate of 1,482/s leads to a rapid loss of cell viability after 10 h of growth. Biochemical and molecular evidences provided below strongly suggest that cell death under high shear results from an apoptosis-like process similar to that described in eukaryotes, with activation of ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20835
更新日期:2006-05-05 00:00:00
abstract::Proteolysis associated with recombinant protein expression in Chinese Hamster Ovary (CHO) cells has hindered the development of biologics including HIV vaccines. When expressed in CHO cells, the recombinant HIV envelope protein, gp120, undergoes proteolytic clipping by a serine protease at a key epitope recognized by ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27016
更新日期:2019-09-01 00:00:00
abstract::In this article, we present the factors which influence the stability of the emulsion forming under the circumstances of the direct extraction of penicillin fermentation broth and the conditions of demulsification. A laboratory method has been developed for testing demulsifiers and a quantitative evaluation of the pro...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260400208
更新日期:1992-06-20 00:00:00
abstract::The effects of ZnCl2 additions on a mercuric reductase, merA, ammonia monooxygenase, amoA, and hydroxylamine (NH2OH) oxidoreductase, hao, gene expression were examined in continuously cultured Nitrosomonas europaea cells. The reactor was operated for 85 days with a 6.9 d hydraulic retention time and with four successi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22069
更新日期:2009-02-01 00:00:00
abstract::The effect of the water content on the lipase-catalyzed (Candida rugosa) interesterification (acidolysis) of menhaden oil with conjugated linoleic acid was studied for amounts of added water ranging from 0-4% (w/w). The rate of the acidolysis reaction increased with increasing water content, but the corresponding perc...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10223
更新日期:2002-06-05 00:00:00
abstract::This paper describes batch and semicontinuous acetic acid fermentations for wine vinegar production carried out with Acetobacter pasteurianus, and an industrial strain using a noncommercial 100-L bubble column reactor equipped with a novel type of gas-liquid dynamic sparger. Results showed acetification rates with thi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19990420)63:2<141::aid-bit
更新日期:1999-04-20 00:00:00
abstract::To monitor gas reaction rates in animal cell culture at constant dissolved oxygen concentration (DO) and constant pH it was necessary to develop improved control methods. Decoupling of both controllrs was obtained by manipulation of molar fractions of oxygen and carbon dioxide in the gas phase. Two pairs of DO and pH ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260450107
更新日期:1995-01-05 00:00:00
abstract::Disulfide-rich peptides isolated from cone snails are of great interest as drug leads due to their high specificity and potency toward therapeutically relevant ion channels and receptors. They commonly contain the inhibitor cystine knot (ICK) motif comprising three disulfide bonds forming a knotted core. Here we repor...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25993
更新日期:2016-10-01 00:00:00
abstract::Fungal morphology in many filamentous fungal fermentations leads to high broth viscosity which limits oxygen mass transfer, and often results in reduced productivity. The objective in this study was to determine if a simple, fed-batch, process strategy-pulsed addition of limiting-carbon source-could be used to reduce ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10548
更新日期:2003-04-05 00:00:00
abstract::Fast and efficient production of recombinant proteins for structural and functional studies is a crucial issue for research and for industry. To this end, we have developed an efficient system to generate in less than 2 months, starting from the cDNA, pools of CHO cells stably expressing high-level of recombinant prot...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22698
更新日期:2010-06-01 00:00:00
abstract::The productivity of Escherichia coli as a producer of recombinant proteins is affected by its metabolic properties, especially by acetate production. Two commercially used E. coli strains, BL21 (lambdaDE3) and JM109, differ significantly in their acetate production during batch fermentation at high initial glucose con...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980105)57:1<71::aid-bit9
更新日期:1998-01-05 00:00:00
abstract::Medium-chain-length-polyhydroxyalkanoic acids (MCL-PHAs) formed in Pseudomonas spp. have a rather broad distribution of monomer-units whose precursors are supplied via beta-oxidation degradation of MCL fatty acids fed as the carbon source and/or via PhaG enzyme catalyzing the acyl-group transfer from 3-hydroxyacyl-ACP...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22149
更新日期:2009-03-01 00:00:00