摘要:

AbstractReverse osmosis is shown to be a viable process for the concentration of highly labile antibiotic solutions. Mathematical n10deJs of antibiotic inactivation by chemical and biological contamination are proposed and correlated with experimental data. Procedures for obtaining high antibiotic recoveries are discussed.

ISSN:0006-3592    

DOI:10.1002/bit.260191002

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

年代:1977

数据来源: WILEY

摘要:

AbstractA kinetic model has been developed which describes the dynamic response of activated sludge to changes in substrate concentration. The well known phenomenon of “growth‐rate hysteresis” can be explained by the simple yet biologically reasonable hypotheses of the model. Experimental results have verified the model quantitat

ISSN:0006-3592    

DOI:10.1002/bit.260191003

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe efficiency of conversion of the carbon‐energy source to product is of primary importance in many fermentation processes. In order to assess the efficiency of a process, one must know how close the actual conversion yield is to the theoretical maximum. Theoretical conversion yields are useful, therefore, as guides in improving a process. This knowledge is particularly important today because the cost of raw materials is rapidly rising. In this study, the biochemical pathway of penicillin synthesis was used to estimate the theoretical yield of penicillin from glucose, ammonia, and sulfate. These values are compared with experimental data from the literature. An analysis of the role of glucose in the synthesis of cell mass and penicillin and in the maintenance of cells makes it possible to assess the efficiency of carbon‐source utilization and to direct further advances in penicillin fermentati

ISSN:0006-3592    

DOI:10.1002/bit.260191004

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn a previous article, the method of preparation and the physical properties of porous (75 to 80% porosity) cellulose beads were described (Biotechnol. Bioeng.,18, 1057 (1976)). The present article reports that the chemical procedures employed for immobilizing enzymes on ordinary cellulose can be applied to the porous cellulose beads. The results showed more enzyme loading on the beads than ordinary cellulose. The choice of the procedures might also affect the mechanical strength of the cellulose beads.

ISSN:0006-3592    

DOI:10.1002/bit.260191005

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

年代:1977

数据来源: WILEY

摘要:

AbstractA pilot scale rotating biological contactor (RBC) was set up near a coal mine at Hollywood, Penn. to evaluate ferrous iron, Fe(II), oxidation. Acid drainage from this mine entered the treatment unit which consisted of four sets of plastic disks affixed to a rotating central shaft. As the disks rotated half immersed in the flowing mine water, iron‐oxidizing bacteria, presumed to beThiobacillus ferrooxidans, colonized the disk surfaces with an average population of 70,000 cells/cm2and mediated the transformation of Fe(II) to the less soluble ferric state, Fe(III). Kinetics of microbial Fe(II) oxidation were established during an eleven month period of continuous pilot operation and were found to follow a concentration dependent first order relationship. Operating at an optimum disk rotation rate and hydraulic loadings of 2.7 and 5.4 gal/day‐ft2(0.11 and 0.22 m3/day‐m2) resulted in the oxidation of an average 240 mg/liter influent Fe(II) to produce effluent Fe(II) of 2 and mg/liter, respectively. The RBC appears potentially useful as a first step in the total treatment of acid mine dra

ISSN:0006-3592    

DOI:10.1002/bit.260191006

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

年代:1977

数据来源: WILEY

摘要:

AbstractLipase (EC 3.1.1.3., fromPseudomonassp.) was entrapped in collagen membrane containing liquid crystal (4‐methoxybenzilidene‐4′‐n‐butylaniline). The activity of the lipase–liquid crystal membrane at an applied voltage of 4 V was 3.4 compared to a membrane tested without imposition of an external electric field. A linear relationship was observed between the activity of the lipase–liquid crystal membrane and the current. The apparent Michaelis constant (K′m) of the lipase–liquid crystal membrane under electric field was identical to that of the membrane under ordinary condition. Activation of the lipase–liquid crystal membrane was observed repeatedly, i.e., activation in the presence of an electric field and reversion to a basal level upon removal of the field occurred cyclically. Activity control of immobilized enzymes is desirable for switching devices of a bioreactor. Possible mechanisms of the lipase activation by electric

ISSN:0006-3592    

DOI:10.1002/bit.260191007

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

年代:1977

数据来源: WILEY

摘要:

AbstractA mathematical model for simulation of oxygen transfer in airlift fermentors is presented. The airlift fermentor is represented by a number of interconnected compartments, each of which is assumed to be well mixed. In the annular region, the model includes both upflow and downflow for the gas phase. The model contains several adjustable parameters through which important hydrodynamic effects affecting oxygen transfer are incorporated. The effect of hydrostatic pressure is also included in the model. The model is simple enough to be used in design studies and it can be easily adapted to other airlift system configurations. The simulation results show good qualitative agreement with available experimental results.

ISSN:0006-3592    

DOI:10.1002/bit.260191008

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

年代:1977

数据来源: WILEY

摘要:

AbstractA continuous high‐speed horizontal colloid mill of novel design for use in the microbiological and food industries was tested for the disintegration of cells ofSaccharomyces cerevisiaeandCandida utilis. The mill consists of a horizontal vessel with round or oval cross sections fitted with a high‐speed longitudinal agitator shaft on which are mounted disk agitators, alternating radially and obliquely to the shaft. The mill is partly filled with freely moving grinding elements which, during a continuous operation, are maintained in the vessel by a vibrating annular slot separator. Highly efficient cooling is provided by circulation of cooling fluid through a jacket surrounding the vessel as well as through the agitator shaft and disks. The radial agitator disks impart a radial motion to the grinding elements, while the oblique disks give rise to the axial movement of a substantial part of the elements. The crossing of paths thus achieved gives the mill a very high efficiency. Using a mill of 20 liter nominal capacity, the effects of agitator design, agitator speed, flow rate, and concentration of the cell suspension on the disintegration efficiency and heat production were studied. Ninety per cent ofS. cerevisiaecells in a 15% suspension could be broken at a residence time of 2.5 min. The temperature rise did not exceed 8° C. The corresponding figure forC. utiliswas 84%. The maximal flow rate was 400 liter/hr. Extrapolation indicates that available industrial mills of 300 liter capacity based on the same design can handle flows of 2000 lite

ISSN:0006-3592    

DOI:10.1002/bit.260191009

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

年代:1977

数据来源: WILEY

摘要:

AbstractTwo different types of biochemical oxygen demand (BOD) sensors using microbial electrodes were prepared. First, a microbial electrode using the bacteria–collagen membrane and oxygen electrode was used for the determination of BOD. When the electrode was inserted in a sample solution containing glucose and glutamic acid (model waste water), the current of the electrode decreased markedly with time until a steady state was reached. A linear relationship was observed between the steady state current and the concentration of the standard solution containing glucose–glutamic acid or the BOD of the solution. The BOD of industrial waste waters can be estimated within 15 min by using the microbial electrode. No decrease in current output was observed over a ten day period. The reproducibility was determined using the same sample (10% of the standard solution) and was found to be 26.2 ± 2.0 μA (7.5% of the relative standard deviation). Next, a biofuel cell utilizing microbial electrode (immobilizedClostridium butyricum–platinum electrode) was applied to the estimation of the BOD of waste waters. The current of the biofuel cell was decreased markedly with time until a steady state was reached. The steady state current was in all cases attained within 30–40 min at 37°C. A linear relationship was obtained between the steady state current and BOD. The BOD of industrial waste waters can be estimated by using the biofuel cell. Relative error of the BOD estimation was within ±10%. The current output of the biofuel cell was almost constant

ISSN:0006-3592    

DOI:10.1002/bit.260191010

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

年代:1977

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260191011

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

年代:1977

数据来源: WILEY