- Type of paper
: Paper in journal
Title: DEVELOPMENT OF REACTOR MODEL FOR GLUCOSE ISOMERIZATION
CATALYZED BY WHOLE-CELL IMMOBILIZED GLUCOSE ISOMERASE
- Authors:
- Vasić-Rački, Đurđa (51631)
- Pavlović, Nediljko
- Čimek, Sonja
- Draić, Mensura
- Husadić, Bečir (11581)
Journal: Bioprocess Engineering
ISSN: 0178-515
Volume: 7
Year: 1991
Pages: from 183 to 187
Number of references: 12
Language: engleski
Summary: Based on the kinetic constants determined and the
mathematicalmodel for reactor system developed, the performance of axial
flowpacked bed continuous enzyme reactor system was studiedexperimentally
and also simulated with the aid of a computer forultimate objective of
optimization of the glucose isomerasereactor system. A reactor model was
established analogous toheterogeneous catalytic reactor model taking into
account theeffect of fluid mass transfer and reversible kinetics.
Theinvestigated catalyst system consists of immobilized
Streptomycesbambergiensis cells containing the enzyme glucose
isomerase,which catalyzes the izomerization of glucose to fructose.
Keywords: glucose isomerase, enzymatic isomerization of glucose, reactor model
- Type of paper
: Paper in journal
Title: MODELLING OF IMMOBILIZATION PROCESS OF ENZYMES ON POROUS
SUPPORT
- Authors:
- Vasić-Rački, Đurđa (51631)
- Gerina, Anka
- Plavljanić, Čedomir
Journal: Kemija u industriji
Number: 3
ISSN: 0022-9830
Volume: 40
Year: 1991
Pages: from 97 to 103
Number of references: 13
Language: hrvatski
Summary: The enzyme adsorption from finite bath onto porous
sphericalsupport is investigated both experimentally and theoreticallyusing
yeast alcohol dehydrogenase and Lewatit MP-500 ion-exchangereasin as a
model system and it is demonstrated how enzymeadsorption can be modelled.
On the basis od adsorption model amodel for the immobilization process,
which describesquantitatively the process of immobilization of a single
enzymeinto porous solid support, was developed. The experimentalresults
have been analyzed for comparison with the theoreticalmodel predictions.
Predictions based on the model are consistentwith experimental results,
which show that most of the enzyme isconfined to the outer half of the
support.
Keywords: immobilization of yeast alcohol dehydrogenase, modelling of enzyme immobilization process
- Type of paper
: Paper in journal
Title: KONTINUIERLICHE REAKTIONSFUEHRUNG MIT LOESLICHEN ENZYMEN
- Authors:
- Kragl, Udo
- Vasić-Rački, Đurđa (51631)
- Wandrey, Christian
Journal: Chemie Ingenieur Technik
Number: 6
ISSN: 0009-286
Volume: 64
Year: 1992
Pages: from 499 to 509
Number of references: 107
Language: njemački
Summary: Die Arbeit beschreibt im berblick die Verwendung von
Enzym-Ćm- Membran-Reaktoren mit erzwungener Konvektion, beidenen
lsliche Enzyme in einem kontinuierlich durchflossenenReaktionsgefá mit
ć
Hilfe einerUltrafiltrationsmembran zurckgehalten werden. Die
Technik ist amBeispiel der L-Aminosure-Herstellung nach dem
Acylase-Verfahrenim 200 t/a-Maástab kommerzialisiert worden. Sie eignet
sichbesonders fr Multienzymsysteme mit Cofaktorrregenerierung. Diesist am
Beispiel der L-tert-Leucin- Herstellung aus derkorrespondierenden
ŕ-Keto-sure im Kilogramm Maástab gelungen. Anwasserlsliche Polymere
gebundene Coenzyme knnen zusammen mitden Enzymen im Membranreaktor
zurckgehalten werden. Durchgeeignete experimentelle Bedingungen kann der
Verlust durchElution ber die Membran bzw. Desaktivierung fr
dieEnzyme/Coenzyme in vielen Fllen so gering gehalten werden, daáer
wirtschaftlich nicht mehr limitierend ist. So gelang es,Coenzyme bis zu
600000 mal bei kontinuierlicher Reaktionsfhrungim Membranreaktor zu
regenerieren. Am Beispiel der enzymatischenPeptid-Synthese wurden
Raum-Zeit-Ausbeuten von mehr als 25kg/(ld) erreicht. Zur Unterdrckung
unerwnschterParallelreaktionen kann mit extrem hohen
Katalysator-konzentrationen gearbeitet werden, so daá Verweilzeiten bis
unter4 min mglich sind.
Keywords: enzyme membrane reactor, continuous processes with soluble enzymes, enzymatic syntehsis of L-tert leucine
- Type of paper
: Paper in journal
Title: THE CONTINUOUS PRODUCTION OF ACETIC ACID BY
ELECTRODIALYSIS INTEGRATEDFERMENTATION. MODELLING AND COMPUTER SIMULATION
- Authors:
- Eysmondt von, Jorg
- Vasić-Rački, Đurđa (51631)
- Wandrey, Christian
Journal: Chemical and Biochemical Engineering Quarterly
Number: 3
ISSN: 0352-9568
Volume: 7
Year: 1993
Pages: from 139 to 148
Number of references: 15
Language: engleski
Summary: The electrodialysis fermentation method was used to reduce
theeffect of end product inhibition in acetic acid fermentation
byAcetogenium kivui. A complete mathematical model for integratedfermentor
and electrodialyzer was developed. The steady-stateequations representing
the mass balances of integrated systemhave been solved and the results
compared with those obtainedexperimentally. The model predicts a higher
total acetic acidproductivity than for a conventional chemostat fermentor
of 50g/l glucose feed if a glucose feed of 120 g/l is
fermented.Furthermore, the model illustrates the possible
dependenceexisting between accumulated biomass, conversion of
glucose,acetic acid concentration in fermentor, space-time-yield
andseparation efficiency in electrodialyzer.
Keywords: Continuous electrodialysis acetic acid fermentation, modelling of integrated fermentation, modelling of acetic acid electrodialysis
- Type of paper
: Paper in journal
Title: CONTINUOUS PROCESSES WITH SOLUBLE ENZYMES
- Authors:
- Kragl, Udo
- Vasić-Rački, Đurđa (51631)
- Wandrey, Christian
Journal: Indian Journal of Chemistry
ISSN: 0376-4699
Volume: 32
Year: 1993
Pages: from 103 to 117
Number of references: 107
Language: engleski
Summary: This paper surveys the use of continuously
operatingenzyme-membrane reactors with enforced flow where the retentionof
soluble enzymes in the reaction vessel is achieved by means ofan
ultrafiltration membrane. This technique has beencommercialized in the
acylase process for the synthesis ofL-amino acids on a 200 ton/year level.
It is especially usefulfor the application of multi-enzyme systems with
cofactorregeneration. The synthesis of L-tert-leucine from
correspondingŕ-keto acid has been achieved on a kilogram scale.
Coenzymescoupled to water soluble polymers are retained in
themembrane-reactor together with the enzymes. Use of suitableconditions
prevents loss of enzyme and coenzyme by passagethrough the membrane or by
deactivation. Therefore the costs ofenzymes and coenzymes are no longer
limitations for economicprocesses. In the continuously operating
enzyme-membrane reactorregeneration of the coenzyme up to 600000 times was
achieved. Incontinuous peptide synthesis space-time yields 25 kg/(l*d)
wereobtained. To suppress side reactions very high catalystconcentrations
are possible, yielding residence times below 4min.
- Type of paper
: Paper in proceedings
Title: ULTRAFILTRATION AND BIOCATALYSTS
- Authors:
- Vasić-Rački, Đurđa (51631)
- Wandrey, Christian
Proceedings title: SEPARACIJSKI PROCESI V HETEROGENIH SISTEMIH
Language: hrvatski
Place: Maribor, Slovenija
Year: 1992
Pages: from 82 to 93
Meeting: Posvetovanje "Separacijski procesi v heterogenih sistemih"
Held: from 10/13/92 to 10/14/92
Summary: The main application of ultrafiltration in biotechnology is
forthe concentration of extracellular enzymes from dilute solutions,with
simultaneous removal of low molar mass compounds(e.g.salts). These
ultrafiltration devices can also be used forreactions, allowing re-use of
biocatalysts in catalyticprocesses. The main advantage of combining the use
ofbiocatalysts and ultrafiltration membranes in enzyme membranereactors is
that continuous operation and recovery of thereaction product is possible
when using a homogeneous phasesystem.
Keywords: ultrafiltration, enzyme membrane reactor
- Type of paper
: Summary in proceedings
Title: ENZYME REAKTOR WITH ULTRAFILTRATION MEMBRANE: MODELLING
AND APPLICATION IN BIOTECHNOLOGY
- Authors:
- Vasić-Rački, Đurđa (51631)
Proceedings title: III Jugoslovenski simpozijum o hemijskom inenjerstvu
Language: hrvatski
Place: Novi Sad, Vojvodina
Year: 1991
Pages: from 14 to 0
Meeting: III Jugoslovenski simpozijum o hemijskom inenjerstvu
Held: from 01/16/91 to 01/18/91
- Type of paper
: Summary in proceedings
Title: ENZYMATIC ISOMERIZATION OF GLUCOSE IN INTEGRATED
BIOCONVERSION/BIOSEPARATION PROCESS
- Authors:
- Matijaević, Ljubica (82036)
- Plavljanić, Čedomir
- Vasić-Rački, Đurđa (51631)
Proceedings title: III Jugoslovenski simpozijum o hemijskom inenjerstvu
Language: hrvatski
Place: Novi Sad, Vojvodina
Year: 1991
Pages: from 20 to 20
Held: from 01/16/91 to 01/18/91
- Type of paper
: Summary in proceedings
Title: ENZYMATIC RESOLUTION OF RACEMIC COMPOUNDS: MODELLING OF
KINETICS
- Authors:
- Vasić-Rački, Đurđa (51631)
- Wandrey, Christian
Proceedings title: XII. Sastanak kemičara Hrvatske
Language: hrvatski
Place: Zagreb
Year: 1991
Pages: from 278 to 278
Meeting: XII. Sastanak kemičara Hrvatske
Held: from 02/11/91 to 02/13/91
- Type of paper
: Summary in proceedings
Title: INVESTIGATION OF ADSORPTION CHARACTERISTICS OF GLUCOSE AND
FRUCTOSE USING THE MOMENT ANALYSIS TECHNIQUE
- Authors:
- Matijaević, Ljubica (82036)
- Vasić-Rački, Đurđa (51631)
Proceedings title: XII. Sasatanak kemičara Hrvatske
Language: hrvatski
Place: Zagreb
Year: 1991
Pages: from 280 to 280
Meeting: XII. Sastanak kemičara Hrvatske
Held: from 02/11/91 to 02/13/91
- Type of paper
: Summary in proceedings
Title: MODELLING OF COUNTER-CURRENT ADSORPTION SYSTEM FOR
SEPARATION OF GLUCOSE/FRUCTOSE MIXTURES
- Authors:
- Matijaević, Ljubica (82036)
- Plavljanić, Čedomir
- Vasić-Rački, Đurđa (51631)
Proceedings title: XIII. Skup hrvatskih kemičara
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 321 to 321
Meeting: XIII. Skup hrvatskih kemičara
Held: from 02/08/93 to 02/10/93
- Type of paper
: Summary in proceedings
Title: SEPARATION OF OXYTETRACYCLINE AND NEUTRAL PROTEINASE FROM
FERMENTATION BROTH WITH AQUEOUS TWO_PHASE SYSTEM
- Authors:
- Bogdan, Stjepan
- Gosak, Darko
- Vasić-Rački, Đurđa (51631)
Proceedings title: XIII. Skup hrvatskih kemičara
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 326 to 326
Meeting: XIII. Skup hrvatskih kemičara
Held: from 02/08/93 to 02/10/93
- Type of paper
: Summary in proceedings
Title: MATHEMATICAL OPTIMIZATION OF MEDIUM COMPOSITION
- Authors:
- Husadić, Bečir (11581)
- Vasić-Rački, Đurđa (51631)
Proceedings title: XIII. Skup hrvatski kemičara
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 335 to 335
Meeting: XIII. Skup hrvatskih kemičara
Held: from 02/08/93 to 02/10/93
- Type of paper
: Summary in proceedings
Title: AEROBIC MICROORGANISMS OXIDATION ACTIVITY DETERMINATION<
EXPERIMENTAL METHOD DEVELOPMENT
- Authors:
- Pavlović, Nediljko
- Mihaljević, Kreo
- Plavljanić, Čedomir
- Vasić-Rački, Đurđa (51631)
Proceedings title: XIII. Skup hrvatskih kemičara
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 338 to 338
Meeting: XIII. Skup hrvatskih kemičara
Held: from 02/08/93 to 02/10/93
- Type of paper
: Summary in proceedings
Title: DYNAMIC OXYGEN ELECTRODE METHOD FOR MEASUREMENT OF kLa
- Authors:
- Plavljanić, Čedomir
- Husadić, Bečir (11581)
- Vasić-Rački, Đurđa (51631)
Proceedings title: XIII. Skup hrvatskih kemičara
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 339 to 339
Meeting: XIII. Skup hrvatskih kemičara
Held: from 02/08/93 to 02/10/93
- Type of paper
: Summary in proceedings
Title: A SEMI_CONTINUOUS ADSORPTION SYSTEM FOR SEPARATION
GLUCOSE/FRUCTOSE MIXTURES
- Authors:
- Matijaević, Ljubica (82036)
- Plavljanić, Čedomir
- Vasić-Rački, Đurđa (51631)
Proceedings title: Sixth European Congress on Biotechnology
Language: engleski
Place: Firenza, Italija
Year: 1993
Pages: from 27 to 28
Meeting: Sixth European Congress on Biotechnology
Held: from 06/13/93 to 06/17/93
Summary: An efficient separation of fructose from glucose may be
achievedin semi-continuous adsorption system. In this work mixtures
ofglucose and fructose are separated in columns packed with LewatitMDS
1368. The characteristics of equilibrium and kineticproperties of the
adsorbent were determined from response curvesby liquid chromatography in
the same column. The mathematicalmodel was developed to calculate
concentration profiles in theadsorber where the adsorption isotherm are
represented by twolinear equations independent of each other. On the basic
of thismodel is an optimal ratio of process parameters (feed/eluent)where
the effectiveness of separation in counter currentadsorption system can be
improved.
- Type of paper
: Summary in proceedings
Title: EFFICIENCY OF SEPARATION OF GLUCOSE/FRUCTOSE MIXTURES
- Authors:
- Matijaević, Ljubica (82036)
- Plavljanić, Čedomir
- Vasić-Rački, Đurđa (51631)
Proceedings title: CHISA '93
Language: engleski
Place: Prag, Čeka
Year: 1993
Pages: from 131 to 131
Meeting: The 11th International Congress of Chemical Engineering, Chemical Equipment Design and Automation
Held: from 08/29/93 to 09/03/93
Summary: In this work, chromatographic separation of glucose and
fructosewith columns of exchange resins was studied by pulse
responseexperiments. Moments analysis technique was used. Theexperimental
eluation profiles of each sugar were used forresearch of influence of
several parameters on the efficiency ofseparation such as length, diameter
of column, retention time andvolumen of resin. The efficiency decreases as
the flow ratebecomes lower at the longer column, while the
efficiencyincreases to a certain flow rate at the shorter column.
- Type of paper
: Summary in proceedings
Title: CONTINUOUS SYNTHETIC REACTIONS OF OLEIC ACID ESTER
CATALYZED BY LIPASEIN ENZYME MEMBRANE REACTOR
- Authors:
- Vasić-Rački, Đurđa (51631)
- Plavljanić, Čedomir
- Coric, Ljubica
Proceedings title: SIXTH EUROPEAN CONGRESS ON BIOTECHNOLOGY
Language: engleski
Place: Firenza, Italija
Year: 1993
Pages: from 177 to 177
Meeting: Sixth European Congress on Biotechnology
Held: from 06/13/93 to 06/17/93
Summary: Esterification as reversal of the hydrolytic reaction will
befavored thermodinamically by the removal of water. Therefore
theultrafiltration membrane reactor dividing oil and water phaseswas used.
The same reactor enables the use of immobilized lipaseon the lipid-water
interface with high reactivity toward theinsoluble substrate. A comparison
of lipase activity in thereactor based on the lipase immobilized to the
"lipid-water"interface to the reactor without membrane was made. The
kineticstudies using oleic acid and glycerol as a model compounds forthe
lipase catalyzed esterification were carried out with theenzyme membrane
reactor system operated in a batch or continuousmode. A dynamic model of
the process was developed. The modelbased on separately determined
parameters for the kinetic data,membrane surface area and process
conditions was verifiedexperimentally.
- Type of paper
: Ph.D.
Title: THE STUDY OF SEPARATION OF GLUCOSE/FRUCTOSE MIXTURES
Faculty: kemijskog inenjerstva i tehnologije Zagrebačko
Date of defense: 07/14/92
Language: hrvatski
Number of pages: 136
Summary: In this work a simulated counter-current adsorption system
wasused to separate two components with different adsorptionselectivity.
The resin Lewatit MDS 1368, showed itself asadsorbent for the separation of
glucose-fructose mixtures.
The mathematical model was developed to calculate concentrationprofiles in
the adsorbers where the adsorption isotherms wererepresented by linear
equation. Concentration profiles werecalculated from dispersed flow model,
and the validity of themodel was proposed experimentally confirmed. On the
basis of thismodel a theoretical system analysis was carried out showing
thatthere is an optimal ratio of process parameters (feed/eluent)where the
effectiveness of separation in counter currentadsorption system can be
improved.
Keywords: adsorption isotherm, counter-current system, glucose/fructose separation
- Type of paper
: Mentorship
Title: IMMOBILIZATION OF MICROBIAL CELLS Streptomyces
bambergiensis
Faculty: kemijskog inenjerstva i tehnologije Zagrebačko
Mentor: ADLER NEVENKA
Date of defense: 03/27/91
Number of pages: 94
Author: Bijelić mr Jasenka
Degree level: M.A.
- Type of paper
: Mentorship
Title: THE KINETIC STUDY OF ENZYMATIC ESTERIFICATION OF OLEIC
ACID
Faculty: kemijskog inenjerstva i tehnologije Zagrebačko
Mentor: ADLER NEVENKA
Date of defense: 01/27/94
Number of pages: 76
Author: Husić Irvaz
Degree level: M.A.
- Type of paper
: Mentorship
Title: THE STUDY OF SEPARATION OF GLUCOSE/FRUCTOSE MIXTURES
Faculty: kemijskog inenjerstva i tehnologije Zagrebačko
Mentor: ADLER NEVENKA
Date of defense: 07/14/92
Number of pages: 136
Author: Matijaević Ljubica
Degree level: Ph.D.