摘要:

AbstractPolyclonal anti‐BSA antibodies were ractionated by stepwise elution from an immobilized BSA column by decreasing pH or increasing the concentration of NaSCN. The binding affinities of each fraction and original globulin under physiological conditions and their dependence on pH and ionic environments were compared. Fractions with high association constant under physiological conditions did not necessarily show antigen binding affinity over a wide pH range, but they retained a high affinity at higher ionic strength of NaSCN. Consequently, by combining these two fractionation procedures, a fraction with high affinity and which dissociated at moderate pH was obtained. It is clear that high affinity is not always incompatible with ease of dissociation accompanying a change in condition

ISSN:0006-3592    

DOI:10.1002/bit.260310702

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractAspen (Populus tremuloides) and black cottonwood (Populus trichocarpa) organosolv pulps produced in a wide range of solvent composition (between 30 and 70% by volume of methanol) and catalysts (H2SO4and H3PO4) such that the cooking liquor pH ⩽ 3 are easily digested by enzymes. The total yields of hydrolysis residues (pulps) are in the 40–60% range; the acid‐catalyzed delignification followed by enzyme hydrolysis can generate 70–88% of the original six‐carbon sugars contained in the wood. Glucomannan and arablnogalactan are dissolved into the pulping liquor in the pH range of 2–4.5. Lower pH (⩽3) leads to additional solubilization of six‐carbon sugars. These sugars may be fermented directly. From the insoluble hydrolysis residues, 36–41% conversions of wood into fermentable sugars were obtained after enzyme hydrolysis; the starting feedstocks contain 50.8 and 46.6% hexosans, respectively, for aspen and black cotton‐wood. The kinetics of enzymatic hydrolysis of cellulose can be formally treated as two simultaneous pseudo‐first‐order reactions in which fast and slow hydrolyses of cellulose occur. Correlations between the glucan digestibility and the effect of the pretreatment have been made. The higher residual xylan content reduces the amount of the rapidly hydrolyzable glucan fraction and lowers the glucan digestibility. The proposed simple kinetic treatment is very helpful in assessing the effect of the pretreatment on pulp

ISSN:0006-3592    

DOI:10.1002/bit.260310703

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractBy investigating the effects of four operating variables—volume (V), Ultrafiltration flux (J), enzyme concentration (E), and substrate concentration (S)—on capacity (K) and conversion rate (ε) of a hollow fiber CSTR, the performances of the CSTR and the kinetic constants of the reaction were determined. A model which takes into account the course of fractional conversion (X) according to the modified space–time parameter, τ (integrated form ofV,J,S, andE), was devised by employing the relationship to integrate the equation for the reaction rate of the CSTR and the expression of the modified space time. Correlation of this model and the experimentally obtained results demonstrates that the characteristics for an ultrafiltration membrane reactor for enzymatic hydrolysis by alcalase of plasma proteins are close to those of an ideal CSTR. Optimal scaling up, however, remains dependent on the compromise which may be obtained between capacity and the conversi

ISSN:0006-3592    

DOI:10.1002/bit.260310704

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractDiscrepancies of one pH unit and more have been observed after a few days, between continuous on‐linein situpH measurements and instant off‐line pH measurements during anaerobic digestion of an agroindustrial wastewater. Concomitantly, the electrical resistance across the porous diaphragm of the on‐line electrode increased, and a black clogging developed on its diaphragm. Measurements of the relative liquid junction potential in KCl or Na2S solutions excluded that high concentrations of ions such as, K+, Na+, Cl−, HS−, or S2−were the major cause of the drifts in pH values. It has been possible to limit the rapid increase of the liquid junction potential and the black clogging formation on the porous diaphragm either by acidification and/or by overpressurization of the electrode‐filling liquid. Continuous on‐linein situpH values consistent with instant off‐line pH values over long periods of time have been obtained with a newly designed pH sensor in which a special jellied electrode filling replaced the

ISSN:0006-3592    

DOI:10.1002/bit.260310705

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe ability of all kinds of Greek raisins for the industrial‐scale fermentation related to pH and trace‐element contents is discussed. In the case of raisin extracts of pH 3.2 larger ethanol productivities, yields, and a continuous use of the same yeast culture at a level of 300 batches was obtained. Metals such as Co, Fe, Zn, Cu, Cd, and Pb in all kinds of raisins have been determined using atomic absorption spectroscopy. The raisin varietyTrechumenacontains the smallest amount of Cu, and the varietyPsillacontains 7 times higher concentration thanTrechumena.This is in agreement with the fact thatPsillais the worst kind of raisin andTrechumenathe best for spirit production. This observation is related with experimental results obtained by alcoholic fermentation in a series of synthetic media containing sacharose and different concentrations of cop

ISSN:0006-3592    

DOI:10.1002/bit.260310706

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe optimal feed rate profiles, for fed‐batch fermentation that maximizes the biomass production and accounts for time, are analyzed. The solution can be found only if the final arc of the optimal control is a batch arc, since in this case the final concentrations of substrate and biomass can be determined by ulterior conditions on the mass balance and on the final growth rate of biomass and thus it is possible to solve the resulting time optimal problem by using Green's theorem. This evidences the “turnpike property” of the solution, which tries to spend the maximum time on or at least near the singular arc along which the substrate concentration is maintained constant. The optimality of the final batch arc is related to the time operational cost in the performance index. The sequence of the control depends on the initial conditions for which six different regions, with the respective patterns, have been identified, in case the performance index allows the control sequence to have a final

ISSN:0006-3592    

DOI:10.1002/bit.260310707

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA novel human protein exhibiting erythroid differentiation activity was discovered in the culture fluids of phorbol ester‐stimulated human cells. The differentiation assay system involving Friend virus‐derived mouse leukemia cells was used. THP‐1 cells of myelomonocytic origin were typical producers. 4β‐Phorbol 12‐myristate 13‐acetate (PMA) was essential for inducible excretion of the erythroid differentiation factor (EDF). The factor was stable toward heat and pH (acidic or alkaline) but lost its activity on pronase treatment, which suggested its proteinous nature. After an optimization of the condition, production of EDF was performed on a 200‐L scale for purification

ISSN:0006-3592    

DOI:10.1002/bit.260310708

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA mathematical model was developed to simulate the operation of an activated sludge system with biomass support particles. Based on the results of this simulation study, it would appear that a system with biomass particle supports offers several advantages not offered by conventional systems. These include the ability to resist failure from large hydraulic surges; stable nitrification under transient inhibitory conditions resulting from temperature changes, hydraulic surges, and/or toxic chemicals; and the ability to establish stable operating conditions with respect to both carbon oxidation and nitrification at short hydraulic retention times and low sludge ages.

ISSN:0006-3592    

DOI:10.1002/bit.260310709

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA novel, semicontinuous diffusion fermentation system was used to produce fuel ethanol and a cubed protein feed (CPF) from fodder beets at an intermediate scale. In the process, fodder beet cubes were augered diagonally upward against a flow of 0.26NH2SO4and yeast in a tubular fermentor. Exiting one end of the fermentor was CPF, while fermented beer [6–9% (v/v) ethanol] exited the other end. Retention times for beer and CPF were 264 and 72 h, respectively. Contamination was controlled by maintaining the fermentation pH between 2.1 and 2.6 using H2SO4. Production costs for a greatly scaled‐up (times 1400) conceptual version of this system (using a continuous rather than a semicontinuous processing mode) were projected by calculation to be $0.529/L for 95% ethanol (net of a $0.112/L credit for CPF). The calculated energy balance (energy output‐energy input ratio) was estimated to be 3.04. In calculating the energy balance, the output energy of the CPF and input energy for growing the fodder beets were not included. A design for the scaled‐up plant is p

ISSN:0006-3592    

DOI:10.1002/bit.260310710

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractAlcoholic fermentation of Jerusalem artichoke juice, a natural complex medium, allowed the production of 13% (v/v) ethanol utilizing an inulin‐fermenting strain ofKluyveromyces fragilis, strongly sensitive to ethanol. However, the fermentation of a simple medium with a similar concentration of fermentable sugars (235 g/L) as saccharose stopped prematurely when only 7% (v/v) ethanol had been produced. Differences in the two fermentation profiles were attributed to the significantly lower ethanol tolerance ofK. fragilisIGC 2671 in the simple medium with 2% saccharose as compared with diluted J.a. juice with a similar sugar concentration, in fact, (1) in diluted J. a. juice, growth was possible up to 8% (v/v) added ethanol compared with 6% (v/v) in simple medium and (2) ethanol‐induced inhibition of the specific growth and fermentation rate as well as ethanol‐induced stimulation of the specific death rate were much more drastic in simple medium. Present results show that (1) the complex composition of the medium used for alcoholic fermentation plays a marked role in the ability of the yeast to tolerate and produce ethanol; (2) J. a. juice proved a very appropriate medium for a productive alcoholic fermentation, namely, in processes based on strains with a low ethanol resistance; and (3) to characterize and compare the ethanol tolerance of fermenting yeasts, the standardization of the medium composition must be taken in consider

ISSN:0006-3592    

DOI:10.1002/bit.260310711

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY