Abstract:
:During continuous lipase-catalyzed oleic acid esterification by ethanol in n-hexane, the oleic acid conversion, initially at 95%, decreases to 20% after 2 h. This decrease is caused by the accumulation of the water produced in the course of the reaction in the packed-bed reactor (PBR). In order to improve the PBR efficiency, it is necessary to evacuate the water produced. In this study, different approaches have been tested to control the water content in the PBR during continuous esterification. The first approach consisted in improving the water solubility by increasing the reaction medium polarity. The addition of polar additives to n-hexane, the use of more polar solvents, and the use of solvent-free reaction medium were tested as a means to favor the water evacuation from the PBR. First of all, the use ofn-hexane supplemented with acetone (3 M) or 2-methyl-2-propanol (1 M) enabled the conversion to be maintained at higher values than those obtained in pure n-hexane. The replacement of n-hexane by a more polar solvent, like the 5-methyl-2-hexanone, resulted in the same effect. In all cases, conversions at steady-state were always less than 95%, as obtained in pure n-hexane. This is explained by a decrease in the enzyme activity due to the increase in the medium polarity. Nevertheless, an increase in enzyme quantity allowed 90% conversion to be maintained during 1 week using 3 M acetone amended n-hexane. Good results (a steady-state conversion of about 80%) were obtained when esterification was carried out in a solvent-free reaction medium containing 2 M 2-methyl-2-propanol as a polar additive. The second approach consisted in the evaporation of the accumulated water by use of an intermittent airflow. Although this process did not enable constant esterification rate to be maintained, it did enable the initial conversion (95%) to be restored intermittently.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Colombié S,Tweddell RJ,Condoret JS,Marty Asubject
Has Abstractpub_date
1998-11-05 00:00:00pages
362-8issue
3eissn
0006-3592issn
1097-0290pii
10.1002/(SICI)1097-0290(19981105)60:3<362::AID-BITjournal_volume
60pub_type
杂志文章abstract::Preparative-scale purification of plasmid DNA has been attempted by diverse methods, including precipitation with solvents, salts, and detergents and chromatography with ion-exchange, reversed-phase, and size-exclusion columns. Chromatographic methods such as hydrophobic interaction chromatography (HIC), reversed phas...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10335
更新日期:2002-09-30 00:00:00
abstract::trans-4-Hydroxy- l-proline (Hyp) is an abundant component of mammalian collagen and functions as a chiral synthon for the syntheses of anti-inflammatory drugs in the pharmaceutical industry. Proline 4-hydroxylase (P4H) can catalyze the conversion of l-proline to Hyp; however, it is still challenging for the fermentati...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26818
更新日期:2019-01-01 00:00:00
abstract::Glycosylation is a key critical quality attribute for monoclonal antibodies and other recombinant proteins because of its impact on effector mechanisms and half-life. In this study, a variety of compounds were evaluated for their ability to modulate glycosylation profiles of recombinant monoclonal antibodies produced ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26904
更新日期:2019-04-01 00:00:00
abstract::Benzil was reduced stereospecifically to (S)-benzoin by Bacillus cereus strain Tim-r01. To isolate the gene responsible for asymmetric reduction, we constructed a library consisting of Escherichia coli clones that harbored plasmids expressing Bacillus cereus genes. The library was screened using the halo formation ass...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1191
更新日期:2001-12-20 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::The microfluidic environment provided by implanted prostheses has a decisive influence on the viability, proliferation and differentiation of cells. In bone tissue engineering, for instance, experiments have confirmed that a certain level of wall shear stress (WSS) is more advantageous to osteoblastic differentiation....
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22842
更新日期:2010-11-01 00:00:00
abstract::This article deals with the modeling of the oxygen transfer in an industrial airlift fermentor used for lactic yeast production on whey substrates. The purpose of this study was to improve the understanding of the interactions among the various parameters that govern the oxygen transfer phenomena in this type of ferme...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260390907
更新日期:1992-04-15 00:00:00
abstract::A novel strategy for the maximum production of a biodegradable copolymer, poly(3-hydroxybutyric-co-hydroxyvaleric) acid, P(HB-co-HV), was developed, based on the kinetic parameters obtained from fed-batch culture experiments of Alcaligenes eutrophus. The effects of various culture conditions such as mole ratio of carb...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:
更新日期:1999-03-05 00:00:00
abstract::The objective of this work was to relate macroscopically measurable on-line fermentation parameters such as dissolved oxygen, off-gas oxygen and carbon dioxide, and cell mass, to the controlled production of key intracellular enzymes under carbon limited conditions. Both batch and perturbed batch aerobic fermentations...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260310406
更新日期:1988-03-01 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 have identified an error in the published integral form of the modified Michaelis-Menten equation that accounts for endogenous substrate production. The correct solution is presented and the error in both the substrate concentration, S, and the kinetic parameters Vm , Km , and R resulting from the incorrect solutio...
journal_title:Biotechnology and bioengineering
pub_type: 信件
doi:10.1002/bit.23181
更新日期:2011-10-01 00:00:00
abstract::Chlorophyllide a was coupled with alpha-(3-aminopropyl)-omega-methoxypoly(oxyethylene) (PEG-NH2) to form a PEG-chlorophyllide conjugate through an acid-amide bond. The conjugate catalyzed the reduction of methylviologen in the presence of 2-mercaptoethanol. It also catalyzed the photoreduction of NADP+ or NAD+ in the ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1029
更新日期:2001-01-01 00:00:00
abstract::Bioprocesses operated in batch mode can induce adverse effects like overflow metabolism, substrate inhibition, osmotic inhibition, oxygen limitation, and catabolite repression. To avoid these adverse effects, fed-batch is the predominant operation mode in industrial production. Nevertheless, screening for optimal prod...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27077
更新日期:2019-09-01 00:00:00
abstract::The marine diatom Cyclotella cryptica was grown over a period of 13 months in a 48-m(2) shallow outdoor flume. The use of foil arrays at intervals of 1.2 m to effect systematic vertical mixing in the flume was found to significantly enhance microalgal production (p = 0.006). Average photosynthetic efficiencies (based ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260320204
更新日期:1988-07-05 00:00:00
abstract::Two attractive features of ELISA are the specificity of antibody-antigen recognition and the sensitivity achieved by enzymatic amplification. This report describes the development of a non-enzymatic molecular recognition platform adaptable to point-of-care clinical settings and field detection of biohazardous material...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20537
更新日期:2005-09-20 00:00:00
abstract::Spinner-flask bioreactors have been used for the production of articular cartilage in vitro. The dynamic environment within bioreactors is known to significantly affect the growth and development of the tissue. The present research focuses on the experimental and numerical characterization of the flow field within a s...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10788
更新日期:2004-01-05 00:00:00
abstract::Increasing demand for petroleum has stimulated industry to develop sustainable production of chemicals and biofuels using microbial cell factories. Fatty acids of chain lengths from C6 to C16 are propitious intermediates for the catalytic synthesis of industrial chemicals and diesel-like biofuels. The abundance of gen...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章,评审
doi:10.1002/bit.25205
更新日期:2014-05-01 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::Most biotherapeutic drugs are recombinant monoclonal antibodies which are mostly produced in monoclonal cell lines derived from Chinese hamster ovary (CHO) cells. Various clones expressing a monoclonal recombinant antibody were analyzed and a correlation of the antibody concentration and the relative mRNA level of cal...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24527
更新日期:2012-10-01 00:00:00
abstract::Formaldehyde is a prevalent environmental toxin and a key intermediate in single carbon metabolism. The ability to monitor formaldehyde concentration is, therefore, of interest for both environmental monitoring and for metabolic engineering of native and synthetic methylotrophs, but current methods suffer from low sen...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26455
更新日期:2018-01-01 00:00:00
abstract::A quick technique for determination of kinetic parameters of fermentation processes is proposed and applied to the transformation of D-xylose into ethanol by Pichia stipitis. The commonly used method to evaluate these parameters is based on achieving several steady states. In the proposed procedure, micro(m) and K(s) ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260411117
更新日期:1993-05-01 00:00:00
abstract::We have developed a new cell surface display system using a major outer membrane protein of Pseudomonas aeruginosa OprF as an anchoring motif. Pseudomonas fluorescens SIK W1 lipase gene was fused to the truncated oprF gene by C-terminal deletion fusion strategy. The truncated OprF-lipase fusion protein was successfull...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20399
更新日期:2005-04-20 00:00:00
abstract::In view of the biochemical reaction catalyzed by enzyme powder suspended in a water-insoluble organic solvent, an equation was derived to estimate the amount of water bound to the enzyme powder. With this equation, an apparent adsorption isotherm between free water (water freely dissolved in benzene) and bound water (...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260340613
更新日期:1989-09-01 00:00:00
abstract::The attrition bioreactor (ABR) combines wet ball milling and enzymatic hydrolysis in one process step. It was found that the ABR did not accelerate enzyme deactivation. Interfacial forces, not shear forces, caused the most deactivation. Elimination of the air-liquid interface by covering the reactor substantially incr...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260310106
更新日期:1988-01-01 00:00:00
abstract::Escherichia coli has been the host organism most frequently investigated for efficient recombinant protein production. However, the production of a foreign protein in recombinant E. coli often leads to growth deterioration and elevated secretion of acetic acid. Such observed phenomena have been widely linked with cell...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26943
更新日期:2019-06-01 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::An immobilized enzyme reactor has been developed for the degradation of bilirubin as a potential treatment for neonatal jaundice. It utilizes the enzyme bilirubin oxidase from Myrothecium verrucaria, which in the presence of molecular oxygen converts bilirubin to biliverdin and other products that are much less toxic ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260281011
更新日期:1986-10-01 00:00:00
abstract::We demonstrate a novel application of (13)C pulsed field gradient (PFG) NMR to monitor mass transfer, due to both flow and diffusion, in a 3D complex porous support structure modified by biofilm growth. This enables timescales an order of magnitude larger than previously possible to be accessed with respect to displac...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21913
更新日期:2008-10-15 00:00:00
abstract::Enzymatic bioreactors with both high flow characteristics and mechanical stability based on macroporous poly(2-vinyl-4, 4-dimethylazlactone-co-acrylamide-co-ethylene dimethacrylate) monoliths have been prepared. Covalent immobilization of trypsin on these support is achieved in a single reaction step using the azlacto...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19990105)62:1<30::aid-bit4
更新日期:1999-01-05 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