摘要:

AbstractIsopycnic banding by density gradient centrifugation was used to measure density changes in complexes formed by the immobilization of each of four different immunoglobulins (IgG) (bovine, dog, rabbit, and sheep) on polystyrene latex beads (0.109 ± 0.0025 μm diam). Subtractive measurements of density changes allowed calculation of the mass of immobilized lgG under varying experimental conditions. The immobilization data were correlated with adsorption isotherms which incorporated charge repulsion forces. The effects of pH and NaCl concentration on the immobilization were studied for the latex–bovine lgG system. It was found that the mass of immobilized immunoglobulins was increased from 10 to 20% by removing the lgG from its isoelectric ra

ISSN:0006-3592    

DOI:10.1002/bit.260200802

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe activity of theL‐asparaginase–collagen membrane was 3.4 U/mg membrane (5.8 U/cm2membrane) and the activity yield was 29%. The apparent Michaelis constant of the asparaginase–collagen membrane was 5.9 × 10−3M. The operational half‐life of the immobilized asparaginase column was 35–40 days. TheL‐asparaginase–collagen membrane retained 90% of its original activity after ethylene oxide gas sterilization. The dried membrane stored at room temperature retained its original activity for five months, and the membrane stored in 0.05Mphosphate buffer (pH 8.0) retained its original activity for one week at 37°C. TheL‐asparaginase–collagen membrane tanned with 1% glutaraldehyde was stable against proteolytic enzymes. Complete degradation ofL‐asparagine by theL‐asparaginase–collagen membrane occurred at a low concentration. TheL‐asparagine in dog blood plasma was completely degraded within 20 min by the extracorporal shunt using theL

ISSN:0006-3592    

DOI:10.1002/bit.260200803

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

年代:1978

数据来源: WILEY

摘要:

AbstractStudies to examine the microbial fermentation of coal gasification products (CO2, H2and CO) to methane have been done with a mixed culture of anaerobic bacteria selected from an anaerobic sewage digestor. The specific rate of methane production at 37°C reached 25 mmol/g cell hr. The stoichiometry for methane production was 4 mmol H2/mol CO2. Cell recycle was used to increase the cell concentration from 2.5 to 8.3 g/liter; the volumetric rate of methane production ran from 1.3 to 4 liter/liter hr. The biogasification was also examined at elevated pressure (450 psi) and temperature to facilitate interfacing with a coal gasifier. At 60°C, the specific rate of methane production reached 50 mmol/g cell hr. Carbon monoxide utilization by the mixed culture of anaerobes and by aRhodopseudomonasspecies was examined. Both cultures are able to carry out the shift conversion of CO and water to CO2and hydroge

ISSN:0006-3592    

DOI:10.1002/bit.260200804

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

年代:1978

数据来源: WILEY

摘要:

AbstractPorcine trypsin (EC 3.4.4.4) converted, within approximately 2 hr at 50°C, its 1000‐fold weight of water‐insoluble, heat‐denaturated cheese whey protein into a water‐soluble product. In the course of this digestion, the enzyme increased the α‐amino nitrogen of the protein by a factor of>20, from 0.40 to 9.40%. After digesting the water‐insoluble whey protein, fully active trypsin could be recovered from the soluble digest with the aid of a cellulose‐based affinity adsorbent. The enzyme which was eluted from a column ofp‐aminobenzamidine, bound to succinylated aminododecylcellulose, was fully active and showed essentially unchanged kinetic properties with a synthetic substrate,L‐benzoyl‐argininep‐nitroanilide. It was possible to perform, with the same amount of trypsin, three subsequent and equally effective solubilizations of whey protein, followed by a fourth digestion which still yielded a soluble product, but was considerably slower and incomplete. During each digestion, an estimated 30% of the trypsin was lost. The was not due to a decreased efficiency of the affinity adsorbent, as its trypsin‐binding capacity was essentially unaffected af

ISSN:0006-3592    

DOI:10.1002/bit.260200805

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

年代:1978

数据来源: WILEY

摘要:

AbstractAdsorption of cellulase byTrichoderma virideQM 9414 has been studied with resting and growing cells and equations have been derived to describe the process quantitatively. It has been observed that the adsorption is a purely physical process being dependent only on cell and cellulose concentrations. It has also been demonstrated that adsorption isrequired for the induction of cellulases; some discussions are devoted to this point.

ISSN:0006-3592    

DOI:10.1002/bit.260200806

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

年代:1978

数据来源: WILEY

摘要:

AbstractGlucose oxidation by immobilized glucose oxidase (GlO) and catalase (Cat) has been investigated in batch and continuous reactions for operational studies. The macrokinetics of the process depend on coupled reaction steps and diffusion rates. The problem may be approximated by a simple pseudohomogeneous model taking into account both substrates of glucose oxidase and the intermediate reaction product H2O2. The effectiveness of both enzymes is enhanced in the coupled reaction path, the overall effectiveness nevertheless is very low. H2O2causes the inactivation of both GlO and Cat. The rates of deactivation depend on the oxidation rates of glucose that give different quasistationary levels of H2O2concentration. As a first approximation, the deactivation rates may be described by first‐order reactions with respect to H2O

ISSN:0006-3592    

DOI:10.1002/bit.260200807

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of cellulase treatment on the physical dewatering of primary sewage sludge has been investigated. Although cellulase treatment rapidly increases the sedimentation rate of diluted sludge, no significant advantage has been found in the settling of undiluted sludge. An extract produced from cellulase‐treated sewage sludge has been used as a medium for the growth of yeast with a view to single‐cell protein product

ISSN:0006-3592    

DOI:10.1002/bit.260200808

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

年代:1978

数据来源: WILEY

摘要:

AbstractAs shown in a previous paper, threshold concentrations of lower and intermediate fatty acids inhibit the uptake of inorganic phosphate, growth, and cell division in yeast cells, This paper demonstrates that, apart from these effects, the acids cause an increase in the respiration quotient (RQ), inhibition of CO2fixation, production of ethanol at the expense of anabolic processes, and inhibition of active amino acid transport in the yeastCandida utilis. On the other hand, the threshold concentrations have no effect on intracellular pH. The inhibition of the inorganic phosphate uptake cannot be the sole primary mode of action of fatty acids since the omission of inorganic phosphate in the incubation medium brings about an inhibition of anabolic processes that is lower than that brought about by fatty acids at concentrations still permitting some phosphate uptake, Although 2,4‐dinitrophenol and caproic acid at low concentrations cause an analogous decrease in biomass yield, their combination does not bring about any marked increase in the effect. Considering the physicochemical properties of fatty acids and their preferential action on energy‐requiring processes, one of the key sitesof action can be assumed to be the mitochondrial membrane. Fatty acids might inhibit the transport of anions, especially phosphate, across the membrane, and disturb the membrane potential by affecting the transport protons. The physicochemical properties of fatty acids may also give rise to their binding to other intracellular membranes and to a subsequent interference with the function of the corresponding organel

ISSN:0006-3592    

DOI:10.1002/bit.260200809

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

年代:1978

数据来源: WILEY

摘要:

AbstractA mathematical model has been employed to examine the interplay of reaction and mass transfer in immobilized enzyme systems involving reaction‐generated enzyme poisons. Deactivation rates can be significantly reduced in some cases by catalyzing a purification reaction in which the poison is transformed into an innocuous substance. This conclusion is illustrated experimentally for reaction‐generated H2O2in a continuous‐flow stirred slurry reactor containing glucose oxidase immobilized on activated c

ISSN:0006-3592    

DOI:10.1002/bit.260200810

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

年代:1978

数据来源: WILEY

摘要:

AbstractA preparation of livingArthrobacter simplexcells immobilized in polyacrylamide gel, which showed steroid‐Δ1‐dehydrogenase activity, was studied. The entrapped microorganisms catalyzed the transformation of cortisol to prednisolone and this reaction was followed spectrophotometrically or with the aid of thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). About 40% of the original activity found with free bacteria was retained after immobilization. The steroid dehydrogenase activity of polyacrylamide‐entrappedA. simplexcould be raised to a minor extent in alcoholic solvents or by addition of a cofactor such as menadione. On incubation in various nutrient media, on the other hand, the activity could be increased considerablyl, usually 7–10 times. Possible causes for the observed increase in activity have been investigated, and microbial growth of the original entrapped microorganisms appears to be the major reason. Frozen activated preparations of immobilizedA. simplexshowed only a small loss of activity on storage for at least four months. A semicontinuous batch wise operation with immobilizedA. simplexin different nutrient media was carried out. At the end of the experiment the steroid transformation capacity was 0.5 g steroid per day per g gel (wet

ISSN:0006-3592    

DOI:10.1002/bit.260200811

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

年代:1978

数据来源: WILEY