摘要:

AbstractSeveral bacteria utilizing C1‐compounds as sole carbon sources were grown on these substrates in continuous culture. The molar yield values (g of cell dry wt/mol of substrate utilized) of bacteria which utilize C1‐compounds via the ribulose monophosphate pathway were between 15.7 to 17.3 when grown on methanol; while the molar yield values of bacteria which use the serine pathway for the assimilation of C1‐compounds varied between 9.8 and 13.1. The molar yield values of different bacteria which use the serine pathway decreased as the oxidation levels of the C1‐growth substrates increased. On formaldehyde the values were between 7.2 to 9.6, whereas on formate the values varied from 3.3 to 6.9.It appears that bacteria utilize Cl‐compounds more efficiently via the ribulose monophosphate pathway than via the serine pathway. The oxidation step from methanol to formaldehyde (and from methylamine to formaldehyde) in the bacteria studied may be energy yielding. A comparison has been made between the experimental yield values obtained and theoretic

ISSN:0006-3592    

DOI:10.1002/bit.260181202

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe black yeast‐like fungusRhinocladiella mansoniiNRRL Y‐6272 elaborates an extracellular polysaccharide composed ofN‐acetylD‐glucosamine andN‐acetylD‐glucosaminuronic acid residues in a 2:1 molar ratio. Production of this polymer was studied in 300 ml flasks and 20 liter fermentors. On the basis of glucose utilized, 13% conversion to polymer was obtained in four days at 25°C in medium containing yeast autolysate paste, K2HPO4, MgSO4, ZnSO4,L‐asparagine or urea, andD‐glucose. Nitrogen sources, aeration, agitation, temperature, and salts affected yields.The polymer in diluted fermentation broths was precipitated with ethanol in the presence of an electrolyte and collected by centrifugation. The viscosities of aqueous resolutions containing 1 and 1.5% of the polymer were 9400 cP and 21,500

ISSN:0006-3592    

DOI:10.1002/bit.260181203

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

年代:1976

数据来源: WILEY

摘要:

AbstractGalactose oxidase (E.G. 1.1.3.9) was covalently immobilized to chemically modified porous silica particles by reaction of the native enzyme with pendant benzoyl azide groups on the carrier. The enzyme loading on the carrier was 100–150 units per milliliter. The immobilized enzyme was incorporated into a hardware assembly suitable for the determination of galactose or lactose concentrations in complex biological fluids. The prototype instrument as described is suitable for continuous, on‐line monitoring or discrete sample analysis. Reaction conditions can be readily provided which maintain global first order kinetics within the reactor and strict linearity of the procedure over a wide range of sample concentrations. Auto‐inactivation of the immobilized enzyme can be prevented by K3Fe(CN)6and long‐term reactor stability can be achieved by the periodic application of the reagent to the enzyme reactor

ISSN:0006-3592    

DOI:10.1002/bit.260181204

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

年代:1976

数据来源: WILEY

摘要:

AbstractFor better operational control of the completely mixed oxygen activated sludge process (CMOAS), a study concerning the kinetics, performance, and operational stability of the Ramanathan‐Gaudy model was conducted. Short‐term experiments were conducted at various dilution rates (1/9, 1/6, 1/3, 1/1.5, and 1/1.0 hr−1) by using two recycle solids concentration values (5000 and 10,000 mg/liter). The influent substrate was an actual industrial organic wastewater (soft drink waste) and its concentration was maintained at 1000 mg/liter COD. The hydraulic recycle ratio, α, was maintained at 0.30.It was found that for CMOAS system with constant recycle cell concentration, a “steady state” with respect to reactor biological solids and effluent COD at different dilution rates could be attained. No appreciable dilute‐out of reactor biological solids and substrate was observed up to the dilution rate of 1 hr−1for both systems of differentXR(5000 and 10,000 mg/liter). For the system ofXR= 5000 mg/liter, except the dilution rate of hr−1, the effluent filtrate COD was lower than 100 mg/liter, the aerator biological solids concentration was about 1550 mg/liter, and the COD removal efficiency was higher than 90% for all dilution rates. For the system ofXR= 10,000 mg/liter, the effluent filtrate COD was lower than 71 mg/liter, the aerator biological solids concentration was about 2750 mg/liter, and the COD removal efficiency was higher than 90% throughout all the dilution rates selection in the present study. The value of the Sludge Volume Index (SVI) was the range of 37.0 to 58.5 and provided good settleability of sludge. The sludge yield was 0.53 for the system ofXR= 5000 mg/liter and 0.57 for the system ofXR= 10,000 mg/liter. The carbohydrate and the protein content of the cells were 10.1–21.6% and 35.6–50.6%, respectively.For predicting the reactor biological solid and effluent COD of the CMOAS system by using the Ramanathan‐Gaudy model, two sets of values for the biological kinetic constants should be considered since it provided the best fit of predicted values of the observed values. In the present study, μm= 0.4 hr−1,ks= 92 mg/liter for 1/3 ⩽D⩽ 1, and μm= 0.05 hr−1,ks= 11.1 mg/liter for 1/9 ⩽D<1/3 were used to calculate the predicted values of reactor biologic

ISSN:0006-3592    

DOI:10.1002/bit.260181205

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

年代:1976

数据来源: WILEY

摘要:

AbstractA new device is designed that is suitable for both laboratory‐ and industrial‐scale cultivation of microorganisms, particularly filamentous fungi, on the surface of liquid media. The device reliably ensures the sterility of cultivation, regardless of its duration. Its installation costs are relatively low and maximum production is reached per unit of installation space. In comparison with submerged cultures in fermentors, the proposed mode does not use a high consumption of energy for stirring and aeration (consequently, the duration of cultivation is not an economically relevant factor) and does not require maintenance of complicated equipment. Due to the building and construction of the technological equipment, the production plant is capable of very fast expansion and, when the need arises of very fast and economical liquidat

ISSN:0006-3592    

DOI:10.1002/bit.260181206

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

年代:1976

数据来源: WILEY

摘要:

AbstractDue to the loss of enzymatic activity as a function of time, an alkaline protease, selected for the continuous preparation of protein hydrolysates (J. Boudrant and C. Cheftel,Biotechnol. Bioeng.,18, 1735, 1976), was chemically stabilized by a simple treatment with glutaraldehyde. Two fractions, soluble and insoluble, were obtained. The activities of these two fractions were measured with casein andN‐benzoyl‐L‐arginine ethyl ester (BAEE) as a function of glutaraldehyde concentration used. It was noted that the insoluble fraction was practically inactive with the first substrate and that the heat stability of the soluble form was likewise enhanced. Molecular weights of these two forms were unchanged, but the uv‐spectrum of the soluble form was modified. From amino acid analysis, it appears that this treatment mainly provokes a decrease in lysine

ISSN:0006-3592    

DOI:10.1002/bit.260181207

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

年代:1976

数据来源: WILEY

摘要:

AbstractBatch proteolysis experiments were performed in order to choose a protein–protease system to prepare a correct hydrolysate suitable for the enrichment of soft‐drinks. The system eventually studied was casein–Alcalase.Comparative batch and continuous proteolysis of casein by Alcalase showed that the reaction, which does not exactly follow first order kinetics with respect to the substrate concentration, is inhibited by the reaction products. Furthermore, experiments were done in order to determine the reaction conditions (pH 8.8 in the reactor, casein concentration 5%, 40°C). Determining the molecular weight of Alcalase (43,000) suggested the choice of ultrafiltration membrane PM 30.Studies of continuous proteolysis with the chemically stabilized enzyme retained by the ultrafiltration reactor showed that protease reuse for seven days at 40°C is possible and that the growth of microorganisms is practically inhibited under these conditions. Gel chromatography showed the molecular weight range of the peptides to be less than 2,000. Triangular taste tests showed that the threshold identification concentration of the dry hydrolysate in orange juice is abou

ISSN:0006-3592    

DOI:10.1002/bit.260181208

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

年代:1976

数据来源: WILEY

摘要:

AbstractA doubling of cellulase production byTrichoderma viride(QM9414) is possible by increasing the cellulose concentration in the medium from 0.75 to 2%, increasing the nitrogen concentration, and controlling pH during growth. A four‐to fivefold increase in β ‐glucosidase is found with the higher cellulose concentration. Culture filtrates from 2% cellulose cultures can reduce the hydrolysis time in a practical saccharification to one‐half that required by culture filtrates from 0.75% cellulose cu

ISSN:0006-3592    

DOI:10.1002/bit.260181209

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe amide bond at N‐6 in succinyl‐NAD was found to be more stable than in former accounts. Succinyl‐NAD was coupled on polylysine to give a new polymer derivative of NAD, which retained at least 85% of the initial coenzymic activity even after dialysis for one week. The polymer derivative of NAD could be applied to a membrane reactor containing alcohol dehydrogenase and lactate dehydrogenase and lactate was continuously produced in a half‐life of t

ISSN:0006-3592    

DOI:10.1002/bit.260181210

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

年代:1976

数据来源: WILEY

摘要:

AbstractSince steroids are only slightly soluble in the aqueous solutions in which enzymatic reactions take place, it is difficult to obtain high effective concentrations per unit reactor volume when enzymes are used to catalyze steroid reactions. In order to obtain high effective concentrations in the present work, we have used small particles of a hydrophobic polymer, poly (dimethyl siloxane), as a reservoir for the steroid substrate and product. The activity of a bacterial hydroxysteroid dehydrogenase in a buffer solution declines much more slowly in the presence of those polymer particles than in the presence of a comparable amount of butyl acetate or ethyl acetate, the organic solvents used as steroid reservoirs in previous work with steroid transforming enzymes. When another substrate of the hydroxysteroid dehydrogenase is loaded into the polymer particles and the particles are suspended in an aqueous solution containing the enzyme and its cofactor, more product is formed that when a similar solution is emulsified with butyl acetate.

ISSN:0006-3592    

DOI:10.1002/bit.260181211

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

年代:1976

数据来源: WILEY