摘要:

AbstractPurification of partially purified fibrinolytic enzyme was attempted by chromatography on DEAE‐cellulose (D‐52) column. The results indicated the resolution of three protein components and one minor component. It was shown that the first component was the major of the applied sample. Examination of fibrinolytic activity of the different fractions of components one and two indicated that only the first component possessed fibrinolytic activity. Fibrinolytic activity of the applied sample was completely recovered by the first enzyme component, and the most active fraction of this enzyme component showed 3.3‐fold purification. The pure fibrinolytic enzyme was relatively more stable at pH 6.98, which was also optimal for its activity. After heating the enzyme solution (pH = 6.98) at 55 and 60°C for 15 min, the enzyme still retained 34.7 and 17.3% of its original activity, respectively. Zinc ions partially inhibited the enzyme. Copper ions activated the enzyme. Iodine partially inhibited the fungal fibrinolytic enzyme at a final concentration of 10−4M; at 10−2Mcomplete inactivation was brought about. Thep‐chloromercuribenzoate at a final concentration of 10−2Mbrought about partial inhibition whereby the enzyme lost about 33% of its original activity. Reduced glutathione brought about activation of the enzyme, while trypsin inhibitor did not show any effect on e

ISSN:0006-3592    

DOI:10.1002/bit.260260502

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

年代:1984

数据来源: WILEY

摘要:

AbstractPyridoxaminephosphate oxidase (EC 1.4.3.5, deaminating) that was partially purified about 40‐fold from dry baker's yeast was immobilized to iodo‐ and bromoacetyl polysaccharides. The most effective carrier was an iodoacetyl cellulose, to which almost complete activity of pyridoxine 5′‐phosphate oxidase was immobilized in 0.02Mpotassium phosphate buffer (pH 8.5) containing 2Mammonium sulfate at 4°C. The immobilized enzyme was more stable than the purified, soluble enzyme against heat and pH change. It was confirmed thatN‐(5′‐phosphopyridoxyl)‐L‐serine was degradedly oxidized to pyridoxal 5′‐phosphate and L‐serine by the immobilized enzyme as comparable rate as pyridoxine 5′‐phosphate, whereasN‐(5′‐phosphopyridoxyl)‐D‐serine did not serve as substra

ISSN:0006-3592    

DOI:10.1002/bit.260260503

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe implementation of adaptive control for a fed‐batch culture in order to maximize the output of product based on a self‐adjusting model is discussed in the present work. Optimization methods were applied to the generalized mathematical model of a fed‐batch fermentation process to determine control algorithms that could be used for on‐line process control. The efficiency of the proposed adaptive algorithms was investigated by simulating a model system. The model of amylotytic enzyme fermentation that was proposed by the authors was taken from a real process. Dynamic modelling has shown that the main problem of realization is connected with the on‐line identification of the adaptive model's parameters. To avoid this problem, we have introduced special limitations on the parameters' time variations that increased the convergence of the identification algorithm. The results of the investigation have shown the efficiency of the proposed adaptive algorithms, and the results of this work should be investigated for real proces

ISSN:0006-3592    

DOI:10.1002/bit.260260504

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

年代:1984

数据来源: WILEY

摘要:

AbstractAlkali treatment and steam explosion of bagasse were investigated in order to develop economical and effective methods of increasing the digestibility of bagasse. The treated bagasse was to be used as a substrate for the production of volatile fatty acids by anaerobic acidogenic bacteria. The alkalis examined were NaOH, NH3(aqueous), NaOH + NH3, Ca(OH)2, and Ca(OH)2+ Na2CO3, at ambient temperature and in combination with steam explosion at 200°C, 6.9 MPa, and 5 min cooking times. Digestibilities of up to 733 g organic matter (OM)/kg bagasse dry matter (DM) were obtained for bagasse treated with NaOH and Ca(OH)2+ Na2CO3; less than 430 g OM was obtained for bagasse treated with aqueous NH3; and up to 724 g OM was obtained for bagasse treated with Ca(OH)2. This digestibility was only achieved by using high concentrations of Ca(OH)2, i.e., 180–300 g/kg bagasse. Steam explosion increased the digestibility of bagasse up to 740 g OM in the presence of alkali but only to 610 g OM in the absence of alkali. The digestibility of bagasse without pretreatment was 190 g OM/kg bagasse DM. More than one‐half the hemicellulose present was solubilized by pretreatment. The composition of the liquid fraction of steam‐exploded material was examined and contained mainly xylose monomers and oligomers (112 g/kg original bagasse DM) and acetic acid (33 g/kg original DM). The relative costs of the alkalis used were obtained for the United States, Australia, and Europe. Lime [Ca(OH)2] was the least expensive alkali per unit of additional digestible OM obtained. Ammonia was the most expensive alkali to use, except in the United States where the difference in its cost relative to other alkalis was smaller. However, ammonia provides organic nitrogen for microbial growth, and could be recycled. With acidogenic fermentations, alkali is able to double as a neutralizing agent during fermentation. Thus, concentrations of alkali equal to that required for neutralization may be used in pretreatment. Concentrations of Ca(OH)2as high as 300 g/kg bagasse were needed for neutralization and should, therefore, be considered for pretreatment. Steam explosion of bagasse resulted in digestible, sterilized substrates of small particle size with readily separable liquid and pulp s

ISSN:0006-3592    

DOI:10.1002/bit.260260505

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

年代:1984

数据来源: WILEY

摘要:

AbstractFungi of theAspergillussp. can hydroxyate biphenyl to 4,4′‐dihydroxybiphenyl, a chemical intermediate used in the plastics industry. The authors studied various batch culture conditions for the production of 4,4′‐dihydroxybiphenyl, byAspergillus toxicarius, in 25‐mL shake flasks and 2‐L fermenter cultures. Conditions investigated included temperature, aeration, carbon and nitrogen sources, biomass content, and time of substrate addition. Under optimum conditions we observed a rate of 4,4′‐dihydroxybiphenyl production of 15–20 mg/day/g dry wt mycelia. Such a production rate is probably too low to support a commercial process and possible reasons for the low productiv

ISSN:0006-3592    

DOI:10.1002/bit.260260506

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis article presents results obtained when some modern estimation and control techniques are applied to a simulated fermentation process. The control structure uses a particular observer of the substrate concentration and assumes the biomass concentration is measurable. The overall structure has been tested for both external and parametric disturbances, with very good results.

ISSN:0006-3592    

DOI:10.1002/bit.260260507

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

年代:1984

数据来源: WILEY

摘要:

AbstractPurified human α1proteinase inhibitor, a plasma glycoprotein with a molecular weight of 5.3 × 104daltons and a major serine protease inhibitor has been covalently coupled to dextrans with molecular weights of 1.77 × 104and 1.03 × 104daltons. The coupled conjugates were soluble in aqueous medium and stable up to 6 months at +5°C. Increased moles of dextran/mole protein ratio during coupling resulted in progressive decreases of inhibitory capacity, immunogenicity, and the association constant (kassoc) between the enzyme and the inhibitor. Compared to the native protein, the soluble conjugates showed improved stability at pH 3.0 and heat stability at 60°C. At 60°C, no loss of inhibitory capacity has been seen up to 60 min for the conjugates during which time the native protein lost greater than 90% of its inhibitory capacity. The presence of antioxidant catalase was needed to prevent oxidative degradation by hydrogen pe

ISSN:0006-3592    

DOI:10.1002/bit.260260508

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe analysis of a continuous, aerobic, fixed‐film bioreactor is performed by simulating the behavior of penicillin production in a three‐phase fluidized bed. Rigorous mathematical models are developed for a fluidized‐bed fermentor in which bioparticles are fluidized by the liquid medium and air. The steady‐state performance of the fluidized‐bed reactor is appraised in terms of penicillin productivity and outlet concentration by considering the two extremes in contacting patterns, complete back‐mix and plug flow, in the absence of a growing biofilm. The results show that the complete back‐mix contacting pattern is preferred over that of plug flow due to the nature of the penicillin kinetic relationships. It is also shown that for the dual‐nutrient (glucose and oxygen) penicillin reaction system the optimum biofilm thickness does not equal the penetration depth of a limiting nutrient, but depends upon the total reacto

ISSN:0006-3592    

DOI:10.1002/bit.260260509

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe dynamic analysis of a continuous, aerobic, fixed‐film bioreactor has been performed. Rigorous mathematical models have been developed for a fluidized‐bed fermentor with biofilm growth. The transient performance of the reactor is appraised in terms of outlet penicillin concentration for constant, as well as variable carbon substrate feed rates. The effect of the reactor oxygen transfer capacity is elucidated for those cases employing substrate feeding strategies. The results show that penicillin production in a continuous, fixed‐film bioreactor reaches a maximum with processing time, but subsequently decreases as cell mass accumulates and substrate deficiencies occur. The maximum production level can be maintained for increased operating times if the substrate supply is continuously increased. The duration of this prolonged production is a direct function of the rate of increase and the operating time at which the increase is initiated. The oxygen transfer capacity of the reactor was found to be important to the effectiveness of a feeding str

ISSN:0006-3592    

DOI:10.1002/bit.260260510

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

年代:1984

数据来源: WILEY

摘要:

AbstractEffluent from the caustic extraction stage of a bleach plant is highly colored due to the presence of dissolved products from lignin chlorination and oxidation. Color removal from the effluent by hydrogen peroxide at neutral pH was catalyzed by addition of horseradish peroxidase. The catalysis with peroxidase (20 mg/L) was observed over a wide range of peroxide concentrations (0.1mM–500mM), but the largest effect was between 1mMand 100mM. The pH optimum for catalysis was around 5.0, while the basal rate of noncatalyzed peroxide color removal simply increased with pH within the range tested (3–10). Peroxidase catalysis at pH 7.6 reached a maximum at 40°C in 4 h assays with 10mMperoxide, and disappeared above 60°C. Compared with mycelial color removal byCoriolus versicolor, the rate of color removal by peroxide plus peroxidase was initially faster (first 4 h), but the extent of color removal after 48 h was higher with the fungal treatment. Further addition of peroxidase to the enzyme‐treated effluent did not produce additional catalysis. Thus, the peroxide/peroxidase system did not fully represent the metabolic route used by the

ISSN:0006-3592    

DOI:10.1002/bit.260260511

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

年代:1984

数据来源: WILEY