ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Digitale Medien

Adaptive on-line model for aerobic Saccharomyces cerevisiae fermentation (1995)

von Schalien, Randolf ; Fagervik, Kaj ; Saxén, Björn ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 48 (1995), S. 631-638

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): Saccharomyces cerevisiae ; fermentation ; on-line simulation ; state estimation ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: In order to study and control fermentation processes, indirect on-tine measurements and mathematical models can be used. In this article we present a mathematical on-line model for fermentation processes. The model is based on atom and partial mass balances as well as on equations describing the acid-base system. The model is brought into an adaptive form by including transport equations for mass transfer and unstructured expressions for the fermentation kinetics. The state of the process, i.e., the concentrations of biomass, substrate, and products, can be estimated on-line using the balance part of the model completed with measurement equations for the input and output flows of the process. Adaptivity is realized by means of on-line estimation of parameters in the transport and kinetic expressions using recursive regression analysis. These expressions can thus be used in the model as valid equations enabling prediction of the process. This makes model-based automation of the process and testing of the validity of the measurement variables possible. The model and the on-line principles are applied to a 3.5-L laboratory tormentor in which Saccharomyces cerevisiae is cultivated. The experimental results show that the model-based estimation of the state and the predictions of the process correlate closely with high-performance liquid chromatography (HPLC) analyses. © 1995 John Wiley & Sons, Inc.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bit.260480611

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

2

Digitale Medien

Kinetics of chlorinated ethylene dehalogenation under methanogenic conditions (1995)

Skeen, Rodney S. ; Gao, Jianwei ; Hooker, Brian S.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 48 (1995), S. 659-666

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): methanogenic activity ; ethylene ; dechlorination ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Kinetics were determined for methanogenic activity and chlorinated ethylene dehalogenation by a methanol-enriched, anaerobic sediment consortium. The culture reductively dechlorinated perchloroethylene (PCE) to trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), vinylchloride (VC), and ethylene and ethane. The absence : of methanol or the addition of 2-bromoethanesulfonic. acid in the presence of methanol suppressed both methanogenic activity and dechlorination. In contrast, acetate production continued in the presence of 2-bromoethanesulfonic acid. These results suggest that dechlorination was strongly linked to methane formation and not to acetate production. A kinetic model, developed to describe both methanogenesis and dechlorination, successfully predicted experimentally measured concentrations of biomass, methane, substrate, and chlorinated ethylenes. The average maximum specific dehalogenation rates for PCE, TCE, 1,1-DCE, and VC were 0.9 ± 0.6, 0.4 ± 0.1, 12 ± 0.1, and 2.5 ± 1.7 μmol contaminant/ g. DW/day, respectively. This pattern for dechlorination rates is distinctly different than that reported for transition metal cofactors, where rates drop by approximately one order of magnitude as each successive chlorine is removed. The experimental results and kinetic analysis suggest that it will be impractical to targeting methanol consuming methanogenic organisms for in situ ground-water restoration. © 1995 John Wiley & Sons, Inc.

Zusätzliches Material: 4 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bit.260480614

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

3

Digitale Medien

Enhancement of antibody production by growth factor addition in perfusion and hollow-fiber culture systems (1995)

Omasa, Takeshi ; Kobayashi, Masaki ; Nishikawa, Toshio ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 48 (1995), S. 673-680

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): bovine serum albumin ; growth factor ; hollow-fiber culture ; perfusion culture ; antibody production rate ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: The effects of the high-molecular-weight growth factors, transferrin and bovine serum albumin (BSA), on antibody production were analyzed quantitatively in continuous hollow-fiber cultivation over a period of 60 days. Transferrin enhanced cell growth but had no significant effect on the specific antibody production rate, whereas BSA significantly enhanced antibody production. The antibody production rate was increased 4- and 14-fold respectively by feeding BSA at 2 and 5 g L-1 into the EC side of the system (the side connected to the cell-containing outer part of the hollow-fiber unit) compared with the production achieved without BSA. Addition of 5 g L1 BSA into the IC side of the system (the side connected to the inner part of the hollow-fiber unit) resulted in a 2.5-fold increase in the antibody production rate. The effect of BSA was also analyzed using the perfusion culture system with a separation unit. When fresh medium containing either 2 or 5 g L-1 BSA was fed into the reactor, both the specific growth rate and specific death rate increased, while the specific antibody production rate was increased 2- and 25-fold, respectively, by feeding BSA at these two concentrations compared with no addition. Comparing the two systems, the increase in the antibody production rate achieved with the hollow-fiber system was threefold greater than that in the perfusion culture system with the same concentration of BSA feeding. © 1995 John Wiley & Sons, Inc.

Zusätzliches Material: 9 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bit.260480616

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

4

Digitale Medien

Ion exchange purification of G6PDH from unclarified yeast cell homogenates using expanded bed adsorption (1996)

Chang, Y. K. ; Chase, H. A.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 204-216

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): expanded bed adsorption ; bakers' yeast ; G6PDH ; STREAMLINE ion exchange adsorbents ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: 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 clarification steps. The purification of G6PDH from an unclarified yeast homogenate was chosen as a model system containing the typical features of a direct extraction technique. Optimal conditions for the purification were determined in small scale, packed bed experiments conducted with clarified homogenates. Results from these experiments were used to develop a preparative scale separation of G6PDH in a STREAMLINE 50 EBA apparatus. The use of an on-line rotameter for measuring and controlling the height of the expanded bed when operated in highly turbid feedstocks was demonstrated. STREAMLINE DEAE has been shown to be successful in achieving isolation of G6PDH from an unclarified homogenate with a purification factor of 12 and yield of 98% in a single step process. This ion exchange adsorbent is readily cleaned using simple cleaning-in-place procedures without affecting either adsorption or the bed expansion properties of the adsorbent after many cycles of operation. The ability of combining clarification, capture, and purification in a single step will greatly simplify downstream processing flowsheets and reduce the costs of protein purification. © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

5

Digitale Medien

Rat hepatocyte morphology and function on lactose-derivatized polystyrene surfaces (1996)

Gutsche, Annie Tang ; Zurlo, Joanne ; Deyesu, Elizabeth ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 259-265

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): hepatocytes ; lactose-derivatized polystyrene ; polystyrene ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Hepatocytes isolated from male Fisher 344VF rats were cultured on two substrates, collagen I and a lactose-derivatized polystyrene (PS-lactose), to compare morphological and functional differences. Hepatocyte morphology changed dramatically depending upon the substrate, shown through actin cytoskeletal staining and scanning electron microscopy. Functional assays performed included albumin secretion, reduced glutathione content, UDP-glucuronosyl transferase, and cytochrome P4501A1 activity. The presence of dexamethasone and dimethylsulfoxide (DMSO) in the media was required for the maintenance of several differentiated functions for cells cultured on collagen. In general, cells cultured on the PS-lactose substrate showed a much slower loss of function over the same period of time. The maintenance of differentiated function of cells on PS-lactose was enhanced with the addition of dexamethasone and DMSO. This is the first report of a culture system in which hepatocytes, cultured on a polymer substrate without additional protein coatings or media additives, have been able to maintain differentiated functions for up to 1 week. © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

6

Digitale Medien

Conservative chemical modification of proteins to study the effects of a single protein property on partitioning in aqueous two-phase systems (1996)

Franco, T. T. ; Andrews, A. T. ; Asenjo, J. A.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 290-299

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): proteins, modified ; partitioning in aqueous system ; thaumatin ; β-lactoglobulin ; BSA ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Relatively conservative modifications of three proteins were carried out to alter their surface properties. The protein properties modified were hydrophobicity and charge. This was done by acylation of amino groups with anhydrides. For the hydrophobic modification experiments, two proteins (β-lactoglobulin and bovine serum albumin [BSA]) and four anhydrides (hexanoic, butyric, succinic, acetic) were used. For the modification of surface charge the protein thaumatin was selected and various proportions of the free amino groups were blocked with acetic anhydride to give a series of proteins with differing isoelectric points. Detailed characterization and purification of selected modified proteins was carried out including molecular weight measurements and conformational analysis. The criteria used for selecting the modified proteins for subsequent investigation of their partitioning in aqueous two-phase systems (ATPS) is described. With a judicious choice of starting material it was found that limited chemical modifications to proteins could effectively alter surface hydrophobicity or charge almost independently, with little effect on other molecular properties. It appears, however, that the method for chemical modification and the reaction conditions must also be carefully controlled. © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

7

Digitale Medien

Use of chemically modified proteins to study the effect of a single protein property on partitioning in aqueous two-phase systems: Effect of surface charge (1996)

Franco, T. T. ; Andrews, A. T. ; Asenjo, J. A.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 309-315

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): surface charge ; proteins, modified ; partitioning in aqueous system ; thaumatin ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: A series of charge-modified thaumatins with different values of surface charge were partitioned in aqueous two-phase systems (ATPS) to study the effect of surface charge as a single property on partitioning. Electrophoretic mobility of the proteins in titration curves was used as a measure of surface charge. Four modified proteins derived from thaumatin with the following values of isoelectric point: 8.70, 8.15, 5.60, and 4.50 were used for partitioning. The resolution of the systems in terms of protein surface charge was calculated. Partitioning of modified thaumatins in PEG 4000/dextran systems with phosphate buffer, Tris buffer, NaCl, KCl, and sulfate salts was carried out. Among the sulfate salts tested, the addition of 50 mM Li2SO4 to the system buffered with phosphate gave the highest value of resolution for differences in surface protein charge (RSPC). It shows a decrease in the value of K (partition coefficient) with an increase in the protein's charge. The addition of 100 mM KCl to the system promoted the opposite effect on the RSPC value. Charge-modified proteins were partitioned in PEG/salt systems to investigate the ability of these systems for resolving differences in surface charge. The PEG/citrate system seemed to have almost no ability for resolving proteins on the basis of surface charge differences; PEG/phosphate systems had some capability for resolving differently charged proteins. The more negative proteins tended to have higher values of K than the more positively charged fractions. The use of charge-modified proteins allowed the investigation of the effect of protein surface charge on partitioning in aqueous two-phase systems independently from other protein parameters as they were prepared from a common parent protein thaumatin. This technique provides an interesting novel tool to investigate the effect of protein surface charge on partitioning in ATPS taking protein charge as an independent parameter. © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

8

Digitale Medien

A versatile oxygenator and perfusion system for magnetic resonance studies (1996)

Gamcsik, Michael P. ; Forder, John R. ; Millis, Kevin K. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 348-354

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): oxygenator ; NMR spectroscopy ; organ perfusion ; mammalian cell culture ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: A compact, reusable membrane oxygenator has been constructed for the perfusion of cultured cells and isolated organs. While the oxygenator was designed to be compatible with nuclear magnetic resonance (NMR) spectroscopy studies, it can also be used for any experiment which requires warming and oxygenation of perfusates. For the NMR studies, the oxygenator can be positioned at the opening of the magnet bore which allows oxygenation and warming of the perfusate immediately prior to delivery to the tissue, therefore eliminating problems with heat or oxygen loss which may occur with the long perfusion lines. © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bit.260490302

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

9

Digitale Medien

Fluid shear stress induction of the transcriptional activator c-fos in human and bovine endothelial cells, HeLa, and Chinese hamster ovary cells (1996)

Ranjan, Vibhu ; Waterbury, Raymond ; Xiao, Zeshuai ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 383-390

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): c-fos protein ; endothelium ; hemodynamics ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: The c-fos protein belongs to a family of transcriptional cofactors that can complex with proteins of the Jun family and activate mRNA transcription from gene promoters containing an activator protein 1 (AP-1) binding element. The shear stress inducibility of the c-fos protein was studied in human and animal cell lines of vastly different origins. Primary human umbilical vein endothelial cells (HUVEC), bovine aortic endothelial cells (BAEC, passage 2-14), HeLa cells, and Chinese hamster ovary (CHO) cells were subjected to steady laminar shear stress using a parallel plate flow apparatus. After 1 h of flow exposure at 25 dyn/cm2, the c-fos levels in nuclei of shear stress HUVEC, BAEC, HeLa, and CHO were 5.4 ± 2.0 (n = 3), 2.25 ± 1.38 (n = 6), 2.14 ± 0.07 (n = 8), 1.92 ± 0.58 (n = 2) times higher, respectively, than in matched stationary controls. Flow exposure at 4 dyn/cm2 caused no enhancement of c-fos levels in any of the cell lines tested, but caused significant reduction in c-fos expression in the HeLa cells. The c-fos induction by shear stress could be blocked by pharmacological agents. For example, the flow induction of the c-fos protein levels was blocked by 50% with the preincubation of HUVEC with a protein kinase C inhibitor, H7 (10 μM) and blocked completely in HeLa cells preincubated with the phospholipase C inhibitor, neomycin (5 mM). The minimum time of shear stress exposure required to induce the c-fos protein expression in HeLa cells was found to be as low as 1 min. By Northern analysis, the c-fos mRNA levels were found to be elevated in BAEC, CHO, and HeLa cells exposed to 25 dyn/cm2 for 30 min. These studies indicate that c-fos induction is a consistent genetic response in a variety of mammalian cells that may alter cellular phenotype in mechanical environments. © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

10

Digitale Medien

Vancomycin production in batch and continuous culture (1996)

McIntyre, James J. ; Bull, Alan T. ; Bunch, Alan W.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 49 (1996), S. 412-420

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3592

Schlagwort(e): Amycolatopsis orientalis ; vancomycin production ; chemostat culture ; phosphate inhibition ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Production of the glycopeptide antibiotic vancomycin by two Amycolatopsis orientalis strains was examined in batch shake flask culture in a semidefined medium with peptone as the nitrogen source. Different growth and production profiles were observed with the two strains; specific production (Yp/x) was threefold higher with strain ATCC 19795 than with strain NCIMB 12945. A defined medium with amino acids as the nitrogen source was developed by use of the Plackett-Burman statistical screening method. This technique identified certain amino acids (glycine, phenylalanine, tyrosine, and arginine) that gave significant increased specific production, whereas phosphate was identified as inhibitory for high specific vancomycin production. Experiments made with the improved medium and strain ATCC 19795 showed that vancomycin production kinetics were either growth dissociated or growth associated, depending on the amino acid concentration. In chemostat culture at a constant dilution rate (0.087 h-1), specific vancomycin production rate (qvancomycin) decreased linearly as the medium phosphate concentration was increased from 2 to 8 mM. In both phosphate and glucose limited chemostats, qvancomycin was a function of specific growth rate; the maximum value was observed at D = 0.087 h-1 (52% of the maximum specific growth rate). Under phosphate limited growth conditions, qvancomycin was threefold higher (0.37 mg/g dry weight/h) than under glucose limitation (0.12 mg/g dry weight/h). © 1996 John Wiley & Sons, Inc.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)