Abstract:
:Highly substituted polychlorinated biphenyls (PCBs) are known to be very resistant to aerobic biodegradation, particularly the initial attack by biphenyl dioxygenase. Functional evolution of the substrate specificity of biphenyl dioxygenase was demonstrated by DNA shuffling and staggered extension process (StEP) of the bphA gene coding for the large subunit of biphenyl dioxygenase. Several variants with an extended substrate range for PCBs were selected. In contrast to the parental biphenyl dioxygenases from Burkholderia cepacia LB400 and Pseudomonas pseudoalcaligenes KF707, which preferentially recognize either ortho- (LB400) or para- (KF707) substituted PCBs, several variants degraded both congeners to about the same extent. These variants also exhibited superior degradation capabilities toward several tetra- and pentachlorinated PCBs as well as commercial PCB mixtures, such as Aroclor 1242 or Aroclor 1254. Sequence analysis confirmed that most variants contained at least four to six template switches. All desired variants contained the Thr335Ala and Phe336Ile substitutions confirming the importance of this critical region in substrate specificity. These results suggest that the block-exchange nature of gene shuffling between a diverse class of dioxygenases may be the most useful approach for breeding novel dioxygenases for PCB degradation in the desired direction.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Brühlmann F,Chen Wdoi
10.1002/(sici)1097-0290(19990605)63:5<544::aid-bitsubject
Has Abstractpub_date
1999-06-05 00:00:00pages
544-51issue
5eissn
0006-3592issn
1097-0290pii
10.1002/(SICI)1097-0290(19990605)63:5<544::AID-BITjournal_volume
63pub_type
杂志文章abstract::This article compares the processes for wheat straw lignocellulose fractionation by percolation, counter-current progressing batch percolation and batch reaction at low NaOH-loadings (3-6% of DM). The flow-through processes were found to improve delignification and subsequent enzymatic saccharification, reduce NaOH-co...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26030
更新日期:2016-12-01 00:00:00
abstract::The design and operation of an industrial penicillin-V deacylation reactor is simulated, using a kinetic expression and mass transport parameters for the immobilized enzyme particles which were determined experimentally in a previous study. It is desirable to use a series of equalsized plug flow reactors with pH contr...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260261213
更新日期:1984-12-01 00:00:00
abstract::In the present investigation molecular sieve has been found to be a suitable carrier for the immobilization of enzymes. From the present study it may be specifically found that trypsin and pappain can be immobilized by molecular sieve type 4a following a very simple techniqure. The immobilized enzyme can be used both ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260190902
更新日期:1977-09-01 00:00:00
abstract::Unsaturated fatty acid alpha-butylglucoside esters were prepared by enzymatic esterification of alpha-butylglucoside in nonaqueous media. Conditions were firstly optimized using oleic acid as acyl group. Synthesis was possible in several solvents but the presence of water co-product in the medium limited the reaction ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19990620)63:6<730::aid-bit
更新日期:1999-06-20 00:00:00
abstract::Oxygen and nutrient limitation was investigated in order to identify the origin of a lower specific ajmalicine production in Catharanthus roseus cultures at high cell densities in an induction medium. The effect of oxygen limitation was explored by comparing two identically aerated and agitated high cell density biore...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260440409
更新日期:1994-08-05 00:00:00
abstract::Ion-exchange (IEX) chromatography steps are widely applied in protein purification processes because of their high capacity, selectivity, robust operation, and well-understood principles. Optimization of IEX steps typically involves resin screening and selection of the pH and counterion concentrations of the load, was...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21905
更新日期:2008-08-01 00:00:00
abstract::Among various routes for the biological hydrogen production, the NAD(P)H-dependent pentose phosphate (PP) pathway is the most efficient for the dark fermentation. Few studies, however, have focused on the glucose-6-phosphate 1-dehydrogenase, encoded by zwf, as a key enzyme activating the PP pathway. Although the gluco...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23259
更新日期:2011-12-01 00:00:00
abstract::Being biosurfactants, rhamnolipids create severe foaming when produced in aerobic Pseudomonas aeruginosa fermentation. The necessary reduction of aeration causes oxygen limitation and restricts cell and product concentrations. In this study, we evaluate the new strategy of rhamnolipid production under denitrification ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/1097-0290(20010105)72:1<25::aid-bit4>3.0.c
更新日期:2001-01-05 00:00:00
abstract::The hollow fiber enzyme reactor with pulsation developed by Kim and Chang (1983) was operated in a differential mode by recycling a substrate solution, in order to assess the efficiency of ultrafiltration swing. The rates of lactose conversion by beta-galactosidase contained in the shell side of the reactor were measu...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260270813
更新日期:1985-08-01 00:00:00
abstract::Flocculation of yeast cells occurs during the fermentation of beer. Partway through the fermentation the cells become flocculent and start to form flocs. If the environmental conditions, such as medium composition and fluid velocities in the tank, are optimal, the flocs will grow in size large enough to settle. After ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980205)57:3<330::aid-bit
更新日期:1998-02-05 00:00:00
abstract::This study conducted quantitative kinetic modeling and in situ and temporally resolved measurements of adsorption, desorption, and re-adsorption of a commercial endoglucanase in lignocellulosic suspensions. The study defined a cellulase adsorption and desorption competition parameter, a pseudo rate of binding and deso...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24483
更新日期:2012-08-01 00:00:00
abstract::This study describes the development and application of a bioaffinity chromatographic system for the one-step purification of an NADP(+)-dependent secondary alcohol dehydrogenase from the obligate anaerobe, Thermoanaerobacter brockii (TBADH, EC 1.1.1.2). The general approach is based upon improving the selectivity of ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10079
更新日期:2002-03-05 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::The use of expanded beds of STREAMLINE ion exchange adsorbents for the direct extraction of an intracellular enzyme glucose-6-phosphate dehydrogenase (G6PDH) from unclarified yeast cell homogenates has been investigated. It has been demonstrated that such crude feedstocks can be applied to the bed without prior clarif...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0290(19960120)49:2<204::AID-BIT
更新日期:1996-01-20 00:00:00
abstract::RNA sequencing (RNASeq) has been widely used to associate alterations in Chinese hamster ovary (CHO) cell gene expression with bioprocess phenotypes; however, alternative messenger RNA (mRNA) splicing, has thus far, received little attention. In this study, we utilized RNASeq for transcriptomic analysis of a monoclona...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27365
更新日期:2020-08-01 00:00:00
abstract::Retroviral-derived biopharmaceuticals (RV) target numerous therapeutic applications, from gene therapy to virus-like particle (rVLP)-based vaccines. During particle formation, beside the pseudotyped envelope proteins, RV can incorporate proteins derived from the virus producer cells (VPC). This may be detrimental by r...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23231
更新日期:2011-11-01 00:00:00
abstract::The kinetics of precipitation of soya protein has been examined in a tubular flow reactor with the precipitants, ammonium sulfate, ethanol, divalent calcium, and sulfuric acid. The precipitate growth profiles obtained in all cases showed the rapid formation of a precipitate phase and the attainment of a final size wit...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280312
更新日期:1986-03-01 00:00:00
abstract::Intracellular delivery of functional proteins is of great interest for basic biological research as well as for clinical applications. Transfection is the most commonly used method, however, it is not applicable to large-scale manipulation and inefficient in important cell types implicated in biomedical applications, ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27245
更新日期:2020-03-01 00:00:00
abstract::The relationship between oxygen concentration and growth rate in the yeast Trichosporon cutaneum was studied. In order to establish the conditions for purely oxygen-limited growth, the cells were first grown in a carbon-limited chemostat, and kinetic parameters determined. The cells were then grown in an oxygen-limite...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260241115
更新日期:1982-11-01 00:00:00
abstract::The feasibility of NO3- removal by the synergistic action of a prevailing denitrifying anoxic methane oxidising (DAMO), and nitrate-reducing and sulfide-oxidising bacterial (NR-SOB) consortium, using CH4 and H2 S from biogas as electron donors in a biotrickling filter was investigated. The influence of NO3- concentrat...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26092
更新日期:2017-03-01 00:00:00
abstract::Polymers produced by horseradish-peroxidase-catalyzed coupling of phenols have been explored as potential substitutes for phenol-formaldehyde resins. To overcome low substrate solubilities and product molecular weights in water, enzymatic polymerizations in aqueous-organic mixtures have been examined. Peroxidase vigor...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260300106
更新日期:1987-07-01 00:00:00
abstract::A number of bioreactor configurations have been developed for the manufacture of products from mammalian cell hosts. Even in the most efficient of these, however, problems such as nutrient exhaustion, growth factor deprivation, and toxin accumulations may arise. Consequently, the current effort focused on the feasibil...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(20000305)67:5<555::aid-bit
更新日期:2000-03-05 00:00:00
abstract::Engineered human T-cells are a promising therapeutic modality for cancer immunotherapy. T-cells expressing chimeric antigen receptors combined with additional genes to enhance T-cell proliferation, survival, or tumor targeting may further improve efficacy but require multiple stable gene transfer events. Methods are t...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25538
更新日期:2015-07-01 00:00:00
abstract::This article describes the synthesis and regulation of beta(1-3)glucanase and protease enzymes from the cell lytic system of Oerskovia xanthineolytica LL-G109 in continuous culture using different concentrations of carbon source (glucose) and inducer (glucan). These two enzyme activities are the main components of a l...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260300507
更新日期:1987-10-05 00:00:00
abstract::In a previous paper, the overall or macrokinetics of the immobilized glucose oxidase--catalase system has been presented. In this paper a detailed analysis of the interaction of diffusion and reaction in this system will be presented. The mathematical treatment includes two consecutive reactions with two-substrate kin...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260211112
更新日期:1979-11-01 00:00:00
abstract::The effector functions elicited by IgG antibodies strongly depend on the carbohydrate moiety linked to the Fc region of the protein. Therefore several approaches have been developed to rationally manipulate these glycans and improve the biological functions of the antibody. Overexpression of recombinant beta1,4-N-acet...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20777
更新日期:2006-04-05 00:00:00
abstract::Cell culture longevity in fed-batch culture of hybridomas is often limited by elevated medium osmolality caused by repeated nutrient feeding. Shotwise feeding of 10x Dulbecco's modified Eagle's medium (DMEM) concentrates elevated the osmolality of medium up to 540 mOsm/kg at the end of fed-batch culture of S3H5/gamma2...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19990105)62:1<120::aid-bit
更新日期:1999-01-05 00:00:00
abstract::Many bacteria used for biotechnological applications are naturally motile. Their "bio-nanopropeller" driven movement allows searching for better environments in a process called chemotaxis. Since bacteria are extremely small in size compared to the bulk fluid volumes in bioreactors, single cell motility is not conside...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21372
更新日期:2007-08-15 00:00:00
abstract::This study demonstrated that hydrogen-producing acidogenic sludge could agglutinate into granules in a well-mixed reactor treating a synthetic sucrose-containing wastewater at 26 degrees C, pH 5.5, with 6 h of hydraulic retention. A typical matured granule is 1.6 mm in diameter, 1.038 g/mL in density, 11% in ash conte...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10174
更新日期:2002-04-05 00:00:00
abstract::Biosorption of elements is a little understood phenomenon exhibited by some types of even nonliving microbial biomass. A common fungus Rhizopus arrhizus has been reported to take up uranium from aqueous solutions to the extent of 180 mg U(6+)/g. The mechanism of uranium sequestering by this type of biomass was studied...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260240211
更新日期:1982-02-01 00:00:00