摘要:

AbstractThe stabilities and optima with respect to temperature and pH of the β‐glucosidase, Avicelase, and carboxymethylcellulase (CMCase) activity ofThermomonosporasp., in the culture filtrate, culture whole broth, and filtrate after sonication of culture solids, are reported. The β‐glucosidase is cell associated and has an optimal activity at about pH 6.5 and 55°C. In the whole culture broth, it has a half‐life of about 8 hr at 55°C and less than 1 hr at 60°C, while the half‐life of the activity in the sonicated, cell‐free filtrate is less than 1 hr at 55°C. The Avicelase and CMCase activities occur in the extracellular culture fluid and have optima at about pH 7.0 and 5.9, and 65 and 70°C, respectively. The CMCase activity is stable over 24 hr at 60°C, but declines by 50% in the same period at 65°C. The Avicelase activity declines by 15% over 24 hr at 55°C, and by 50% at 60°C. The highest pH studied (pH 7.3) was the most destabilizing for all three activities. The thermostable characteristics of the cellulases fromThemomonosporaappear to make them suitable for commercial saccharification processes operating at e

ISSN:0006-3592    

DOI:10.1002/bit.260220802

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

年代:1980

数据来源: WILEY

摘要:

AbstractA saccharification of cellulosic material using culture filtrate from the stationary phase of a culture ofThermomonosporasp. produced primarily cellobiose up to levels inhibitory to further saccharification, while the use of whole broth resulted in the production of glucose as well. Glucose production was enhanced and continued throughout the saccharification (24–36 hr) by several additions of cellobiase activity in the form of culture solids. Using Solka‐Floc as substrate, the “difference sugar” level (total soluble sugar minus glucose) rapidly rose to the same relatively stable concentration under various hydrolysis conditions, which was independent of the total sugar and glucose concentrations. A rapid hydrolusis rate was observed initially during saccharification, followed by a much slower rate of sugar production. Repeated centrifugation of the reaction mixture and replacement of the supernatant with fresh enzyme solution resulted each time in the reinitiation of a rapid hydrolysis rate. Saccharifications using A vicel microcrystalline cellulose, acid‐swollen cellulose, and cotton as substrates were also studied. A modified method of making phosphoric‐acid swollen cellulose is described. Saccharification of this substrate by culture filtrate and sequential additions of culture solids resulted in an inverse relationship between the attained glucose concentration and cellobiose‐cellotriose c

ISSN:0006-3592    

DOI:10.1002/bit.260220803

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

年代:1980

数据来源: WILEY

摘要:

AbstractEnzymatic hydrolysis of insoluble soybean protein by a protease enzyme produced byPenicillium dupontiK 1104, was investigated in a batch reactor. The reaction conditions were 30–55°C and pH 3.4–3.7. The mechanism of solubilization of the insoluble protein by thePenicillium dupontienzyme was deduced from a series of experiments. Kinetic models were developed that involved adsorption followed by peptic digestion of protein, inhibition of low‐molecular‐weight peptides, and enzyme deactivation. The uncoupled kinetic parameters were estimated using the Marquardt nonlinear parameter estimation algorithm. A bang–bang production of soluble and partially soluble protein is suggested for higher productivity. The essential amino acids pattern of the enzyme‐Hydrolyzed soy protein was comparable with the unhydrolyzed protein isolate. Aggregation of the soluble protein for an extended time was observable. The low‐molecular‐weight soluble protein was incorporated into noncarbonated beverages. The amount of protein that could be incorporated into a can of 355 ml noncarbonated beverage, without observable changes in the optical density and also aggregation of the protein, was 2.5 g soluble protein. Beverages with caramel color showed excessive decrease in optical density and precipitation. The kinetics and diffusion in a multipore immobilized‐enzyme recycle reactor will be considered in part

ISSN:0006-3592    

DOI:10.1002/bit.260220804

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

年代:1980

数据来源: WILEY

摘要:

AbstractA single‐stage aerobic continuous process for the conversion of poultry waste into single‐cell protein is described. The slurried manure was supplemented by molasses. Kinetics and possible mechanisms for the suggested conversion‐scheme have been investigated. A Box–Wilson experimental design has been employed to elucidate the effect of environmental conditions on reactor performance. Temperature, pH, and percent solids concentration in the feed (media composition) were the independent process variables, while the minimum residence time for the nearly complete utilization of total uric acid and ammonia nitrogen, the amount of carbon required per gram of nitrogen consumed, and protein content of the product were considered as dependent variables. Optimal environmental conditions for the minimum raw material cost and for the maximum percent protein, lysine, and methionine content of the product were determined. The operating conditions of 25°C, pH 7.5, 1.5% solids in the feed, and a residence time of 8.1 hr were found to be the most appropriate conditions maximizing the “profit” function, which is defined as the difference between the product value and raw m

ISSN:0006-3592    

DOI:10.1002/bit.260220805

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

年代:1980

数据来源: WILEY

摘要:

AbstractTrichoderma virideITCC‐1433 secretes a cellulase complex that is rich in β‐glucosidase and therefore well suited for the saccharification of cellulosic materials. The cellulase was investigated with respect to optimum conditions of reaction and enzyme stability. Avicelase, CMCase, and β‐glucosidase differed considerably in their physicochemical properties. At temperatures above 50°C, β‐glucosidase is not very stable. Therefore, as a compromise the conditions of hydrolysis were chosen to be 50°C and pH 4.5. With the crude culture filtrate ofT. virideITCC‐1433 a nearly pure glucose solution of 4% is reached from a 10% cellulose suspension. Wood pulp and newsprint are hydrolyzed to a much smaller extent. With an enzyme concentrate up to 8% glucose accumulated in the reaction fluid within 48 hr. At this time the glucose‐cellobiose ratio was 75:1. Glucose was demonstrated to be the most potent inhibitor of total hydrolysis. The addition of glucose to the enzyme‐substrate solution at zero time completely stopped its own formation and cellobiose and reducing groups (oligosaccharides) accumulated. By removing glucose through an ultrafilter device about 90% saccharification of cellulose to glucose was achieved in 48 hr without any accumula

ISSN:0006-3592    

DOI:10.1002/bit.260220806

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

年代:1980

数据来源: WILEY

摘要:

AbstractA 22 m long. 20 liter tubular loop fermentor (TLF) has been tested for oxygen transfer characteristics and as a reactor for mycelial growth. Model calculations show that the flow pressure drop has an important influence on the axial oxygen profiles. A design model that accounts for this influence is presented. Using the model,KLavalues are calculated from the results of sulfite oxidation experiments. These are correlated with power consumption and aeration rates. TheKLadependence on aeration rate was found to be less than found with tank reactors. The growth kinetics of three metabolite‐producing mycelial organisms in the TLF are presented: aStreptomyces, aFusarium, and aAcrophialophora. In order to determine the influence of reactor type on the growth and product formation, these cultures have been grown in tanks and shake flasks. The antibiotic, product spectrum ofStreptomycesis compared on the basis of inhibition tests and it is shown that the distribution of products is reactor dependent. TheFusariumculture produced a previously unknown metabolite, whose concentration in the loop fermentor was four times higher than in a shake flask. TheAcrophialophoraculture grew twice as fast in the loop fermentor, but produced essentially none of the specific product. Power Consumptions of up to 8 kW/m3in the tubular fermentor did not appear to harm the myceli

ISSN:0006-3592    

DOI:10.1002/bit.260220807

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

年代:1980

数据来源: WILEY

摘要:

AbstractA “bloom” of the freshwater algaBotryococcus brauniiKützing appeared in the Darwin River Reservoir in 1976. At the time of algal sampling, the "bloom" was estimated at 1500 ton and possibly double this mass at a maximum cell concentration. The alga is characterized by a high liquid hydrocarbon content, sufficient to cause flotation of the algal colonies. This report is an examination of the waters of the reservoir and of the characteristics of the alga. Observations are included on the formation of a material known as Coorongite, a rubbery complex produced by the drying of colony aggregates at the shoreline. Earlier reports of “blooms” ofB. brauniiare reviewed in relation to th

ISSN:0006-3592    

DOI:10.1002/bit.260220808

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

年代:1980

数据来源: WILEY

摘要:

AbstractFlow microfluorometry, which provides detailed information on the state of a microbial population, has been employed to characterize theBacillus subtilispopulation during time intervals in which significant changes in the culture amylase activity occur. Four different batch experiments have been conducted, and the influences of inoculum age, fermentation temperature, and aeration rate on microbial population dynamics and amylase activity have been examined. Relatively high rates of amylase activity increase are observed twice during the batch, first as double cells initiate sporulation and later during germination. Rapid decreases in amylase activity are observed in highly (25–50%) sporulated populations, and in at least one experiment, during a transition from large, rounded protoplast forms to normal rod morphology. Amylase and protease activities do not follow parallel nor proportional trajectories in these 72 hr batch fermentation

ISSN:0006-3592    

DOI:10.1002/bit.260220809

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

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper shows how to treat the substrate‐limiting Monod equation in a straight forward manner for different types of fermentors (plug‐flow, batch, and mixed‐flow) using the general language of chemical reaction engineering. Straight‐line plots are developed for directly finding the kinetic constants of the equation, and an example using Monod's original data illustrates the procedure. The Monod equation is then generalized to account for the effects of both substrate and inhibitory toxic wastes. Finally, for pure product inhibition performance, expressions are derived for various reactor types, and correlation graphs are developed for finding the kinetic constants of the reaction. An example from the recent literature shows that this equation form fits the data extreme

ISSN:0006-3592    

DOI:10.1002/bit.260220810

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe effectiveness of compression‐milling pretreatment of lignocellulosics for enzymatic hydrolysis has been demonstrated for a wide variety of substrate sources. Reductions in the degree of crystallinity and the degree of polymerization of cellulose and partial destruction of the structural integrity of lignocellulosics brought about by compression milling significantly increase the susceptibility of cellulose to enzymatic hydrolysis. The enzymatic hydrolysis yield was found to be directly related to the specific energy input to the cellulosic substrate (kWh/1b substrate) by compression milling, and the energy input can be controlled by the milling time. The enzymatic hydrolysis yeilds from cellulosic materials pretreated by compression milling also vary significantly depending on the source and kind, the composition milling also vary significantly depending on the source and kind, the composition (contents of lignin and other components), and the structure. The power requirements for compression milling which renders equivalent hydrolysis yields also depend on the source and kind of lignocellulosics to be pretreated. For newspaper, the specific energy input required for 55% sugar yield is estimated as 0.3 kWh/lb substrate including 15% power loss. The additional sugar yield gained from the enzymatic hydrolysis of compression‐milled newspaper (over and above the sugar yield of untreated substrate) is determined as 453 g sugar/kWh energy in

ISSN:0006-3592    

DOI:10.1002/bit.260220811

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

年代:1980

数据来源: WILEY