摘要:

AbstractThe growth behavior ofCellulomonashas been examined in fermentation system using alkali pretreated sugarcane bagasse. During the batch operation diauxic growth was found which would not seem to be explained by catabolic repression. The relative variation of cellulose and hemicellulose during the fermentation process suggests the initial utilization of easily degradable substrate, i.e., hemicellulose and amorphous cellulose, until their concentration becomes limiting, followed by utilization of the crystalline cellulose. The conversion of substrate was 70% with a yield of 0.355 g of biomass per gram of bagasse feed.

ISSN:0006-3592    

DOI:10.1002/bit.260230702

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

年代:1981

数据来源: WILEY

摘要:

AbstractA characteristic behavior of the fermentation process was observed during the growth ofCellulomonason sugarcane bagasse. At the early stage of the fermentation the crystallinity index of bagasse increased, suggesting that the major metabolized fraction corresponded to the hemicellulose during this stage. Some time later the crystallinity achieved a steady state and then deceased, which indicated that the most complex structure of bagasse was being attacked. The analysis of the cellulolytic activity of extracellular enzyme in the medium showed a sharp increase followed by an abrupt leveling off and decline in activity. These results along with the reduction of crystallinity index and bagasse utilization (70%) justify the assumption that the C1component was present in the cellulase complex synthesized by the bacteria.

ISSN:0006-3592    

DOI:10.1002/bit.260230703

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe kinetic properties of immobilized and nonimmobilized glucose isomerase have been investigated. In both cases the kinetics can be described by a modified Michaelis–Menten expression. It appeared that immobilization causes no deactivation. Furthermore, it was shown that the permeability of the cell membrane increases by heat and toluene treatment

ISSN:0006-3592    

DOI:10.1002/bit.260230704

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

年代:1981

数据来源: WILEY

摘要:

AbstractGeneral patterns of sucrose fermentation by two strains ofZymomonas mobilis, designated Z7 and Z10, were established using sucrose concentrations from 50 to 200 g/liter. Strain Z7 showed a higher invertase activity than Z10. Strain Z10 showed a reduced specific growth rate at high sucrose concentration while Z7 was unaffected. High sucrose hydrolyzing activity in strain Z7 lead to glucose accumulation in the medium at high sucrose concentrations. Ethanol production and fermentation time depend on the rate of catabolism of the products of sucrose hydrolysis, glucose and fructose. The metabolic quotients for sucrose utilization,qs, and ethanol production,qp(g/g·hr), are unsuitable for describing sucrose utilization byZymomonas mobilis, as the logarithmic phase of growth precedes the phase of highest substrate utilization (g/liter·hr) and ethanol production (g/liter·hr) in batch cultu

ISSN:0006-3592    

DOI:10.1002/bit.260230705

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe obtaining of a fermentable extract from Jerusalem artichoke is simple. Yeasts with inulinase activity can be used to produce ethanol with good profitability. This method makes it possible to obtain 25 to 65 hl ethanol/ha with by‐products usable as fee

ISSN:0006-3592    

DOI:10.1002/bit.260230706

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

年代:1981

数据来源: WILEY

摘要:

AbstractA steady‐state method forkladetermination has been presented using the Michaelis–Menten two‐substrate kinetic equation for oxidation of glucose in the presence of the enzymes glucose oxidase and excess catalase. The conditions have been specified where spontaneous hydrolysis of lactone is sufficiently rapid, thus eliminating inhibitory action of lactone on the oxidation. In glucose oxidase‐free batches, theklavalues were determined using various modification of the dynamic method. The dynamic methods in which gas interchange was effected without interrupting aeration and agitation of the batch yielded erroneously lowerklavalues as compared to the results of steady‐state methods if the measuredklavalue was higher than 0.03 s−1. The values yielded by the dynamic method in which the gas interchange was effected at the same time with turning on aeration and agitation of the batch agreed with values resulting from the steady‐state method provided that the measuredklavalues were lower than 0.08−1and the simultaneous interfacial transport of nitrogen and oxygen had been taken into account in the evaluation. Atklavalues higher than 0.08−1, this modification of the dynamic method also yielded lowerklavalues as compared with the outcome of the steady‐state method. The experiments performed do not, however, allow one to decide unambiguously on the whether these lowerklavalues are due to failure of the adopted model to describe adequately the dynamic behavior of the system or whether they are true values differing from those yielded by the steady‐state method on account of different physical propertie

ISSN:0006-3592    

DOI:10.1002/bit.260230707

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

年代:1981

数据来源: WILEY

摘要:

AbstractIt is conventional to describe the relationship between the specific rate of microbial growth and the concentration of the inhibitory substrate in terms of the Andrews–Edwards equation. A novel method for establishing the constants of this equation is presented. The equation is transformed to a polynomial and the empirical data are approximated by a quadratic polynomial. The results obtained for the biodegradation of phenol in a mixed culture (activated sludge) are discusse

ISSN:0006-3592    

DOI:10.1002/bit.260230708

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

年代:1981

数据来源: WILEY

摘要:

AbstractCandida utiliswas cultivated in a 5‐liter jar fermentor using ethanol as sole carbon source. Control of ethanol in the cultivation broth was performed by using an ethanol vapor monitoring instrument and an oxygen electrode coupled with two control circuits. By setting upper and lower bounds according to the predetermined conditions, a signal from a gas monitoring sensor switched the lower or higher bound relay governing the actuating or switch‐off of the motor; this maintained a proper concentration of ethanol in the cultivation of ethanol in the system. The growth of cells was found to be satisfactory. Cell concentration reached 64 g/liter during a 20‐hr cultivation. As the results of comparative experiments, the control mode using the gas monitoring instrument was found to be superior to that using dissolved oxygen as a controlling signal, especially at high cell concentr

ISSN:0006-3592    

DOI:10.1002/bit.260230709

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

年代:1981

数据来源: WILEY

摘要:

AbstractA pressurized, stirred vessel attached with an ultrafiltration membrane was used as a membrane reactor, Cellobiose hydrolysis by cellobiase was carried out and theoretically analyzed in terms of steady‐state conversion and flow rate through the membrane. When the flow rate exceeds a critical value, a significant fraction of the enzyme inside the reactor is localized in the concentration polarization layer where shear from stirring is high. Consequently, enzyme deactivation inside the concentration polarization layer is accelerated and the conversion decreases due to an exchange of active enzyme in bulk with deactivated enzyme in the polarization layer via convection and back diffusion. Successful operation can be obtained at flow rates lower than the critical point to avoid the polarization and thus the deactivation. It is shown that 6.5 L of 2 mg/mL of cellobiose solution is hydrolyzed to glucose with a conversion of 91% in 20 h with 1.617 mg of cellobiase enzyme, in a reactor attached with a PM 10 membrane of an effective surface area of 39.2 cm

ISSN:0006-3592    

DOI:10.1002/bit.260230710

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

年代:1981

数据来源: WILEY

摘要:

AbstractA simple model for biomass, product, and substrate evolution proposed previously for batch polysaccharide fermentations is extended to multiproduct fermentations. The examples involveClostridium thermocellum,(ATCC 27405)fermentations of glucose to four products (ethanol, acetic, formic, and lactic acid), of fructose to two products (ethanol and acetic acid), and of cellobiose to two products (ethanol and acetic acid). In all cases, parameter evaluation was carried out in a serial deterministic procedure.

ISSN:0006-3592    

DOI:10.1002/bit.260230711

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

年代:1981

数据来源: WILEY