摘要:

AbstractBrazilian needs for petroleum as a primary energy source grew from 13.2% in 1940 to 41.7% in 1977. This resulted in a much greater dependence on foreign sources and prompted the Government to initiate a detailed study of alternatives. The National Alcohol Program established in 1975 is just one of the options being examined. The National Energy Balance forecast shows that annual anhydrous alcohol consumption for automotive purposes should increase from 1.74 × 106m3to 4.7 × 106m3in the period from 1978 to 1987. This paper presents the main objectives of the National Alcohol Program in the context of the overall Energy Program, points out the problems connected with alcohol production and utilization, and reviews the serious problems related to its distribution to the consuming centers. Finally, the indirect benefits resulting from the implementation of the National Alcohol Program are shown, underlining the saving of foreign currency, the substantial increase in employment opportunities, the reduction in regional and individual income discrepancies, and the expansion of capital goods production, together with the improvement of national technology in the agricultural and industrial sector

ISSN:0006-3592    

DOI:10.1002/bit.260221002

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

年代:1980

数据来源: WILEY

摘要:

AbstractContinuous deacetylation of cephalosporin C, 7‐aminocephalosporanic acid, and of 2‐methoxyethyl acetate in packed beds of an immobilized esterase is described by simple empirical equations relating conversion to space velocity and temperature. The choice of process conditions is discussed in relation to the effects of temperature on column efficiency, column life, growth of microbial contaminants, and the rates of thermal decomposition of the substrates. At the preferred temperature of 10°C columns were operated continuously for one month with only small losses in effici

ISSN:0006-3592    

DOI:10.1002/bit.260221003

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

年代:1980

数据来源: WILEY

摘要:

AbstractSaccharomyces cerevisiaeCBS 426 was grown aerobically in continuous culture with a mixture of glucose and ethanol as the carbon source. The flows of biomass, glucose, ethanol, oxygen, and carbon dioxide were measured. A model for growth with two substrates was derived. Application of this model to the above‐mentioned system yielded values forYATPand P/O. The joint confidence regions for these parameters were calculated. The relevance to industrial production of bakers' yeast is discusse

ISSN:0006-3592    

DOI:10.1002/bit.260221004

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

年代:1980

数据来源: WILEY

摘要:

AbstractContinuous production ofL‐alanine fromL‐aspartic acid using immobilizedPseudomonas dacunhaewas investigated.Pseudomonas dacunhaecells were immobilized with carrageenan gel. TheL‐aspartate β‐decarboxylase activity of immobilized cells was enhanced by incubating the immobilized cells with a solution of 1MammoniumL‐aspartate (pH 5.5) containing 0.1mMpyridoxal‐5′‐phosphate (PLP) at 37°C over 20 hr. The enzyme activity of immobilized cells was 59% that of intact cells. The pH profile of the enzyme reaction was broader in the immobilized cells than in the free cells. The enzyme activity of immobilized cells was maintained through repeated uses when a substrate solution containing 0.1mMPLP was used. Complete conversion ofL‐aspartate toL‐alanine was attained when a solution of 2MammoniumL‐aspartate (pH 6.2) containing 0.1mMPLP was passed upward through the immobilized cell column at a retention time of 8 hr at 37°C. Glutaraldehyde treatment of the immobilized cells resulted in a slight decrease of the enzyme activity but a marked increase of the operational stability. The half‐life of enzyme activity was 46 days in glutaraldehyde

ISSN:0006-3592    

DOI:10.1002/bit.260221005

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

年代:1980

数据来源: WILEY

摘要:

AbstractAn investigation of the rotating biological contractor (RBC) process variables to determine the efficiency of biological oxygen demand (BOD) removal is presented. Operating parameters including influent BOD content (<355 mg/liter), flow rate, disk surface area, hydraulic loading, disk rotational speed, liquid retention time, stage number, and wastewater temperature were evaluated. The BOD predictive model was developed using literature data with multiple regression analysis. This study shows that influent BOD concentration, hydraulic loading, stage number, and wastewater temperature are the most significant variables in predicting the RBC system performance. The model presently developed was verified by field data concerned with the treatment of both domestic and low‐strength industrial wastewaters. Also, the results calculated by this model were compared to those obtained from Weng's mode

ISSN:0006-3592    

DOI:10.1002/bit.260221006

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

年代:1980

数据来源: WILEY

摘要:

AbstractCell‐division‐cycle, temperature‐sensitive mutants ofSaccharomyces cerevisiaewere investigated as a means of altering the morphological characteristics and subsequent physical properties of single‐cell protein (SCP). Strain 4471, harboring mutation cdc 4, formed a visible complex mass at the nonpermissive temperature, after being grown at 30°C and then transferred to 37°C for 8 hr. Microscopic observation showed that the mother cell was unable to complete the budding process at the nonpermissive temperature, which caused the cells to enlarge. Viscosity measurements were used to establish and characterize optimum morphological changes in the yeast. The Maximum increase in viscosity occurred when cells were incubated at 30°C and then shifted to 37°C for 8 hr. Strain 4471 exhibited yield stress, whereas A364A did not. Maximum change in yield stress occurred when cells were shifted from 30 to 37°C for 8 hr. No significant loss of protein or RNA occurred in strain 4471, as compared to strain A364A, when incubated at the nonpermissive

ISSN:0006-3592    

DOI:10.1002/bit.260221007

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe applicability of Contois' kinetic equation to aerobic and anaerobic treatments of organic wastes is investigated. A refractory coefficient to account for the nonbiodegradable portion of the organic substrates in the digester is incorporated into the kinetic equation. The kinetic equation is applied to the data for aerobic digestions of organic substrates and for anaerobic treatment of dairy wastes. They all show a very good fit of the kinetic equation to the data. Furthermore, the kinetic parameters and the refractory coefficients are shown to be independent of influent organic substrate concentration. This study confirms previous reports that the effluent quality of biological treatment systems for organic wastes depends on influent organic waste concentration. The effect of temperature on the kinetic parameters and the refractory coefficient for anaerobic treatment of sewage sludge are studied. It shows that the kinetic parameters vary with temperature, while the refractory coefficient remains fairly constant. Equations to predict biodegradable treatment efficiency and volumetric substrate utilization rate are also briefly discussed.

ISSN:0006-3592    

DOI:10.1002/bit.260221008

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

年代:1980

数据来源: WILEY

摘要:

AbstractA methane‐utilizing mixed culture isolated from activated sludge by selective enrichment at 45°C was found to consist of three interacting species: a methaneutilizing bacterium, a citrate‐utilizing bacterium, and a methanol‐utilizing bacterium. All three species grew well at 45°C. Three different stable mixed cultures were reconstituted by various combinations of these pure cultures. The nutritional requirements and substrate ranges for each pure culture were determined. The nutritional requirements and substrate ranges for each pure culture were determined. The saturation constant for the methane‐utilizing bacterium on methane (K CH 4) and for the methanol‐utilizing bacterium on methanol (K CH 3OH) were 1.73 × 10−6Mand 4.51 × 10−7M, respectively. The volumetric mass transfer coefficient for methane (KLa) was d

ISSN:0006-3592    

DOI:10.1002/bit.260221009

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

年代:1980

数据来源: WILEY

摘要:

AbstractA two‐member methane‐utilizing mixed culture of bacteria, formed by combining two pure cultures isolated from a naturally occurring methane‐utilizing mixed culture, was studied in continuous culture. From the nutritional requirements and substrate ranges of the pure cultures, a mechanism for the interspecific interactions occurring in the mixed culture was proposed. Product formation kinetics were determined in continuous culture for each product involved in the proposed mechanism. From this proposed mechanism a mathematical model was derived based on simple material balance equations around a single‐stage chemostat. The steady‐state predictions of this model were compared to experimental results obtained from continuous‐culture experiments with the two‐member methane‐utilizing mixed culture. Interspecific interactions occurring in two‐member methanol‐utilizing and three‐member methane‐utilizing mixed cultures h

ISSN:0006-3592    

DOI:10.1002/bit.260221010

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

年代:1980

数据来源: WILEY

摘要:

AbstractPullulanase was immobilized on tannic acid and TEAE‐cellulose, and β‐amylase was covalently immobilized onp‐aminobenzylcellulose. Both the immobilized enzymes showed similar properties in pH and temperature optima and heat stability. On passing the pullulan solution at high temperature (50°C) through a column packed with immobilized pullulanase, only maltotriose was obtained for ten days and the half‐life was about 15 days. In a continuous reaction using immobilized multienzyme, starch was completely converted into maltose at 50°C and at a space velocity of 1.2, a comparative longer half‐life (20 days) was obtained. It was concluded that starch was smoothly converted into maltose with the aid of α‐amylase contaminated in the immobilized pullulanase and the operational stability of the column increased

ISSN:0006-3592    

DOI:10.1002/bit.260221011

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

年代:1980

数据来源: WILEY