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1.
Effect of Enzyme Modification of Corn Grits on their Properties as an Adsorbent in a Skarstrom Pressure Swing Cycle Dryer 总被引:1,自引:0,他引:1
Corn grits have been tested as a desiccant in a pressure swing adsorption (PSA) system to produce dry air. Two sizes of unmodified corn grits were tested in the PSA system: 2.16 and 0.978 mm in diameter, which dried moist air to dew points of –42°C and –69°C, respectively. A modification technology has been developed for the corn grits that gives an increase in the operational adsorptive capacity in a pressure swing adsorption system, so that they remove as much moisture from air as molecular sieves at the same conditions. After modification, 2.16 mm corn grits dry moist air to a –56°C dew point and the 0.978 mm corn grits dry air to a –80°C dew point. The modification process creates surface modifications on the corn grits apparently making more adsorption sites easily available. The modification procedure increases the specific surface area of the grits and possibly decreases the crystallinity, which would make more hydroxyl groups available for adsorption of water. Possible applications of using corn grits in the pressure swing adsorption system include industrial gas dryers, sorptive cooling air conditioners, and recycling equipment for industrial solvents. 相似文献
2.
Weil Joseph Brewer Mark Hendrickson Richard Sarikaya Ayda Ladisch Michael R. 《Applied biochemistry and biotechnology》1998,(1):99-111
Yellow poplar wood sawdust consists of 41% cellulose and 19% hemicellulose. The goal of pressure cooking this material in
water is to hydrate the more chemically resistive regions of cellulose in order to enhance enzymatic conversion to glucose.
Pretreatment can generate organic acids through acid-catalyzed degradation of monosaccharides formed because of acids released
from the biomass material or the inherent acidity of the water at temperatures above 160°C. The resulting acids will further
promote the acid-catalyzed degradation of monomers that cause both a reduction in the yield and the formation of fermentation
inhibitors such as hydroxymethyl furfural and furfural. A continuous pH-monitoring system was developed to help characterize
the trends in pH during pretreatment and to assist in the development of a base (2.0 M KOH) addition profile to help keep
the pH within a specified range in order to reduce any catalytic degradation and the formation of any monosac-charide degradation
products during pretreatment. The results of this work are discussed. 相似文献
3.
A large amount of inedible plant material, generated as a result of plant growth in a Controlled Ecological Life Support System
(CELSS), should be pretreated and converted into forms that can be recycled on earth as well as in space. The main portion
of the inedible biomass is lignocellulosic material. Enzymatic hydrolysis of this cellulose would provide sugars for many
other uses by recycling carbon, hydrogen, oxygen, and nitrogen through formation of carbon dioxide, heat, and sugars, which
are potential foodstuffs. To obtain monosaccharides from cellulose, the protective effect of lignin should be removed. White-rot
fungi degrade lignin more extensively and rapidly than other microorganisms.Pleurotus ostreatus degrades lignin effectively, and produces edible and flavorful mushrooms that increase the quality and nutritional value
of the diet. This mushroom is also capable of metabolizing hemicellulose, thereby providing a food use of this pentose containing
polysaccharide. This study presents the current knowledge of physiology and biochemistry of primary and secondary metabolisms
of basidiomycetes, and degradation mechanism of lignin. A better understanding of the ligninolytic activity of white-rot fungi
will impact the CELSS Program by providing insights on how edible fungi might be used to recycle the inedible portions of
the crops. 相似文献
4.
Huang TT Taylor DG Lim KS Sedlak M Bashir R Mosier NS Ladisch MR 《Langmuir : the ACS journal of surfaces and colloids》2006,22(14):6429-6437
Channel geometry combined with surface chemistry enables a stable liquid boundary flow to be attained along the surfaces of a 12 microm diameter hydrophilic glass fiber in a closed semi-elliptical channel. Surface free energies and triangular corners formed by PDMS/glass fiber or OTS/glass fiber surfaces are shown to be responsible for the experimentally observed wetting phenomena and formation of liquid boundary layers that are 20-50 microm wide and 12 microm high. Viewing this stream through a 20 microm slit results in a virtual optical window with a 5 pL liquid volume suitable for cell counting and pathogen detection. The geometry that leads to the boundary layer is a closed channel that forms triangular corners where glass fiber and the OTS coated glass slide or PDMS touch. The contact angles and surfaces direct positioning of the fluid next to the fiber. Preferential wetting of corner regions initiates the boundary flow, while the elliptical cross-section of the channel stabilizes the microfluidic flow. The Young-Laplace equation, solved using fluid dynamic simulation software, shows contact angles that exceed 105 degrees will direct the aqueous fluid to a boundary layer next to a hydrophilic fiber with a contact angle of 5 degrees. We believe this is the first time that an explanation has been offered for the case of a boundary layer formation in a closed channel directed by a triangular geometry with two hydrophobic wetting edges adjacent to a hydrophilic surface. 相似文献
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6.
Applied Biochemistry and Biotechnology - 相似文献
7.
Subir K. Basak Ajoy Velayudhan Michael R. Ladisch 《Applied biochemistry and biotechnology》1994,44(3):243-261
Buffers used in electrophoresis and electrochromatography must have a relatively low ionic strength in order to minimize ohmic
heating in the presence of an applied potential. Calculation of pH, ionic strength, and the van Slyke buffer capacity, β,
is therefore important. This paper describes thea priori calculation of these parameters for tris buffer made up with either glycine (a zwitterion) or HCl. A quadratic expression
for pH, valid over wide ranges, is obtained for both buffer systems. The calculated values of pH, ionic strength, and buffer
capacity are shown to agree with experimental results as a function of tris, HCl, and glycine concentrations ranging from
1 to 50 mM. A new parameter, the electrokinetic buffer effectiveness factor, is introduced to characterize buffers being considered
for use in electrokinetic systems such as electrochromatography, and is used to determine the appropriate composition ranges
for the buffer components. 相似文献
8.
Ximenes EA Dien BS Ladisch MR Mosier N Cotta MA Li XL 《Applied biochemistry and biotechnology》2007,137(1-12):171-183
Distillers dried grain with solubles (DDGS) is the major coproduct produced at a dry grind ethanol facility. Currently, it is sold primarily as a ruminant animal feed. DDGS is low cost and relatively high in protein and fiber contents. In this study, DDGS was investigated as carbon source for extracellular hydrolytic enzyme production. Two filamentous fungi, noted for their high cellulolytic and hemicellulolytic enzyme titers, were grown on DDGS: Trichoderma reesei Rut C-30 and Asper gillus niger NRRL 2001. DDGS was either used as delivered from the plant (untreated) or after being pretreated with hot water. Both microorganisms secreted a broad range of enzymes when grown on DDGS. Higher xylanase titers were obtained when cultured on hot water DDGS compared with growth on untreated DDGS. Maximum xylanase titers were produced in 4 d for A. niger and 8 d for T. reesei in shake flask cultures. Larger amounts of enzymes were produced in bioreactors (5 L) either equipped with Rushton (for T. reesei) or updraft marine impellers (A. niger). Initial production titers were lower for bioreactor than for flask cultures, especially for T. reesei cultures. Improvement of enzyme titers were obtained using fed-batch feeding schemes. 相似文献
9.
Pretreatment of corn fiber by pressure cooking in water 总被引:4,自引:0,他引:4
Joseph R. Weil Ayda Sarikaya Shiang-Lan Rau Joan Goetz Christine M. Ladisch Mark Brewer Rick Hendrickson Michael R. Ladisch 《Applied biochemistry and biotechnology》1998,73(1):1-17
The pretreatment of corn fiber using liquid water at temperatures between 220 and 260°C enhances enzymatic hydrolysis. This
paper describes the laboratory reactor system currently in use for cooking of corn fiber at temperatures ranging from 200
to 260°C. The corn fiber at approx 4.4% solid/liquid slurry was treated in a 2-L, 304 SS, Parr reactor with three turbine
propeller agitators and a Proportional-Integral-Derivative (PID), controller that controlled temperature within ±1°C. Heat-up
times to the final temperatures of 220, 240, or 260°C were achieved in 50 to 60 min. Hold time at the final temperature was
less than 10 s. A serpentine cooling coil, through which tap water was circulated at the completion of the run, cooled the
reactor’s contents to 180°C within 2 min after the maximum temperature was attained. Ports in the reactor’s head plate facilitated
sampling of the slurry and monitoring the pH. A continuous pH monitoring system was developed to help observe trends in pH
during pretreatment and to assist in the development of a base (2.0M KOH) addition profile to help keep the pH within the range of 5.0 to 7.0. Enzymatic hydrolysis gave 33 to 84% conversion
of cellulose in the pretreated fiber to glucose compared to 17% for untreated fiber. 相似文献
10.
Pretreatment of yellow poplar sawdust by pressure cooking in water 总被引:11,自引:0,他引:11
Joe Weil Ayda Sarikaya Shiang-Lan Rau Joan Goetz Christine M. Ladisch Mark Brewer Rick Hendrickson Michael R. Ladisch 《Applied biochemistry and biotechnology》1997,68(1-2):21-40
The pretreatment of yellow poplar wood sawdust using liquid water at temperatures above 220°C enhances enzyme hydrolysis.
This paper reviews our prior research and describes the laboratory reactor system currently in use for cooking wood sawdust
at temperatures ranging from 220 to 260°C. The wood sawdust at a 6–6.6% solid/liquid slurry was treated in a 2 L, 304 SS,
Parr reactor with three turbine propeller agitators and a proportional integral derivative (PID) controller, which controlled
temperature within ±1°C. Heat-up times to the final temperatures of 220, 240, or 260°C were achieved in 60–70 min. Hold time
at the final temperature was less than 1 min. A serpentine cooling coil, through which tap water was circulated at the completion
of the run, cooled the reactor’s contents within 3 min after the maximum temperature was attained. A bottoms port, as well
as ports in the reactor’s head plate, facilitated sampling of the slurry and measuring the pH, which changes from an initial
value of 5 before cooking to a value of approx 3 after cooking. Enzyme hydrolysis gave 80–90% conversion of cellulose in the
pretreated wood to glucose. Simultaneous saccharification and fermentation of washed, pretreated lignocellulose gave an ethanol
yield that was 55% of theoretical. Untreated wood sawdust gave less than 5% hydrolysis under the same conditions. 相似文献